shinajaran

[game] Shogun2 Legandary difficulty level for Tokugawa clan pt2

2012-02-14T10:26:00.000+08:00

Perseverance my friends. After countless events of total annihilation by my rival daimyos', my army turned against me, rebellion created by enemy monks. I survived until turn 220.

The methodologies to win the war are rather idiosyncratic. War is all about money and economics.

My shogunate could not progress at the tech tree at a faster pace then my rivals. Hence my soldiers are mainly regular yari ashigaru and bow ashigaru with the exception few units of sword samurai. My castles are 2 level below my rivals and the production speed of my soldiers are rather limited. Most of the time, my army was outnumbered. I learned to let go my ego of banging head on with the hardened enemy and circumvent them using my newly devised methods.

Having said that amassing a large fleet of ships, large contingent of army and agent units are very taxing on the finance for the rival state. I make a good guess on the financial status and the rice supply status. At every turn, maybe my rivals are not making enough profit to cover the new army created.

If you guys could recall months back game play at turn 45, I have a couple of metsuke (secret police) running around, coupled with some monks and ninjas.

My metsukes' was leveled up regularly by apprehending rival agent units at each and every turn. The success rate of apprehending grow slowly from 20% to 95%. While level up, I would choose to develop the bribery skill to the highest level. Usually, the apprehending would be successful, because Tokugawa clan specialty have a +2% of success rate.

I did level up my ninjas' too. Sabotaging rival rice plantations at every turn. This would decrease the rice supply by -1. Beside rice plantations, structures such as castle gate, rice merchant, tea house are possible targets too. If rival army are marching near to my territory, my ninja would sabotage the army to buy me time to lay an ambush. The skill sets of the ninja are build towards the "Ninjutsu" at level6. After my ninjas were leveled up, I start the process of assassinating rival generals, to make the rival army bare naked without the positive influence of a general.

As for my monks, I send them far back into enemy lines, creating rebellion at poorly garrison castle. Of course, along the way I would use my monks to convert the enemy agent units.

The above 3 steps requires very little money to sustain. The bulk of my profit goes to building elite shock troops. It really took a very long time to build army that are truly useful.

With my newly acquired army, sufficiently trained agent units and MONEY. The journey of clearing the Hatakeyama clan eastwards begin. At that point of time, having war at both sides of my border is a strict no no to the financial status. At the west borders, I have my agent units sabotaging enemy army and preventing them from marching to my land. At the east borders, my army is still outnumbered by the rivals. Good thing is, not every army are lead by a general. I would use my metsuke to attempt to bribe this category of army. Once successful, I would march my army near to this newly acquired army and enter battle with the rival and try to outnumber them. Once the enemy retreat or loses the battle, I attack the castle and loot the castle. Looting gave my shogunate a 20K income. Remember to set the newly acquired castle to no tax and put a metsuke to oversee the town, just in case of rebellion.

With the new money, I could attempt to bribe more army. Some army are lead by general. Simple, send in the ninja to attempt assassination. If successful, send in the metsuke to bribe. If successful again, merger the new army with the current ones I have. Send in a ninja to sabotage the castle gate before sending in the merged army of mine. If successful, loot the castle. My rival clan recruited super elite units such as Bow hero, Sword Hero, Yari Hero, Great Guards and more. Bribing this army would make this units at my disposal. Indirectly, my army get level up without upgrading my castle facilities.

The cycle repeats itself again. With some variations along the way of course.

revenge is sweet.

Game statistics suggesting the gruesome path that leads to the rising of my Tokugawa clan.

I have created 4 vassal states, just to trade with. Trading will increase the financial profit. Occasional rebels were created by my monks. Then I would send in my generals to put out the rebellion. Indirectly, my generals get to level up!

The characteristic of the Tokugawa clan requires the training of the arts, rather than bushido.

Taxes are on the high side, but the populations are happy! Just train the Daimyo with lots of honour.

One of my awesome general with the traits of "Intimidating"

One of my awesome army with awesome agent units.

Check out my save game

http://db.tt/3ZkCU8aJ

[Arduino] 4x4x4 LED cube

2012-02-07T15:09:00.000+08:00

I was really caught up with work, as always but I will try to update as frequent as possible.

back in 2009, I came across the idea of making 3x3x3 LED cube as part of the teaching material for programming, electronics , and leading the concept to computer engineering.
http://shin-ajaran.blogspot.com/2009/06/diy-3x3x3-led-cube.html

Now at late 2011/ early 2012 one of my project students, Eagle. He picked up the idea and superseded my 3x3x3 with his creation of 4x4x4 LED cube with some really awesome electronics circuit skills and soldering skills... that is soldering of 48LEDs into 3 layers, each layer consist of 16LEDs, with a XYZ+ (I lost count of it) solder joints. IMBA!! To make life easier he is making this into an arduino shield for those that are interested to pick it up easily (minus the hassle of soldering, just plug and play).

Now hook it up to the arduino microcontroller. 4pins to control the layers , 4+4 pins to control the individual LEDs at each layer, 4 analog pins to control the dimming effect. Displaying of patterns on the LED cube requires the idea of refreshing the pattern at a high speed, to give human an illusion that there is animation. In actual fact, the LED just took turn to light up, one by one.

now, code time. This code can be quite scary, looking at the binary pattern used to display the led pattern and using progmem to store the "animations". The code was adopted from an instructable.

The end product is totally worth the hours put in to this pet project! Check it out~

Next stage, would be modifying the circuit to use LED driver chip MAX7221. Luckily I bought some during my last visit to Shen Zhen.

I brought this LED cube around, like a young boy showing off his geeky toy. Upload to my facebook account just to attract some interest.... Little did I know, one of my programming class student surfaced with his 3x3x3 LED cube that he has made.... And the voyage to kernel begins...
check this out yo!

[arduino] RGB led, Introducing LOLSs

2011-11-11T13:50:00.002+08:00

Introducing LOLSs, an arduino shield made by my student lihsheng using uln2003a darlington.
LOLSs is an acronym, which stands for LED O' LihSheng shield. It uses 3PWM on arduino to control brightness of RGB LEDs. If we use digital output instead of PWM, we could only turn on and off the LED, which is ..... BORING. Supply is 12V, can support about 6RGB LEDS (that is 3x8 LEDs in total)
Behold...

The component side of stripboard is soldered on the connecting copper side instead

Now about RGB LED, in each of them there are 3 LEDs in total which is Red Green and Blue. Red is 2.2v, Blue and Green is 3.5v. Hence we need to use resistors such as 150ohm and 80ohm respectively to limit the current. If not, the LEDs will be burnt. Here, I tested my RGB LED with 1.5v, hence the dim green colour.

This is how the RGB led strip looks like. We would need a LED driver circuit to power up long stretch of them. LOLSs can drive up to 6RGB LEDs with 12v 800mAH NiCad battery.

There are 4 "legs" from a normal LED, the longer leg is the anode which we connect the +ve side of VCC. The shorter legs are the cathode which we connect -ve or gnd.

Now, how can we wire the LEDs to the arduino?

check out these diagrams by ADAFRUIT

Now, the fun part. Programming the RGB LED. We could do several of the below in code.

1. Light the colour one by one

2. Fade the brightness of the RGB LEDs with PWM. There is example code to fade 1 LED. It is available at Examples->Basics->Fade

3. Mix colour of the RGB LED. the value of RGB LED follow this format [255,255,255]. For each colour, 0 to turn off, 255 to turn on. Any values in between is to change the brightness. If all 3 led is 255, what is the resulting colour=? WHITE

3. Make the colour change according to music

4.etc etc

Here is my rendition of RGB led with Arduino, based on the sample code given.

code here

[game] Shogun2 Legandary difficulty playing for Tokugawa clan

2011-11-03T14:48:00.001+08:00

I am playing Shogun2 since the last 2 months and you know what, medieval2 last me for a whole 3.1 years! I played all factions and difficulty level. lol

This campaign is VERY challenging. I got wipe out, annihilated, humiliated, sieged at 10:1 and more.
After a few tries for loosing at the 3-4th turn and the last 40game restarts I did not manage to clear the 30th turn mark.

Let me give some background information about shogun2 tokugawa clan at Legendary difficulty level.
I started off as vassal for Imagawa with 2000gold, 2 generals, 1unit of yari samurai, 2units each of yari ashigaru and ashigaru archers. I have a metsuke (secret police, good in maintaing order while taxing the population) too. Being a vassal means my overload gets 50% of my $$ and i can only wage a war which pisses off my boss. Politically, putting me at a very passive position. I will explain more later... less income means I can't afford big/elite armies. The whole objective of the game at the early stage is to shake off the vassal status by either Imagawa declare war on me, which hurts their daimyo reputation and diplomatic score or let other enemy rummage over Imagawa. Based on the art of war of sun-tzu, if I let my friend's enemy attack my "friend" and borders me too early, i am in big trouble. 唇亡齿寒

At the start of the game, Oda clan is my arch nemesis and they are marching on my land. Which means, my income from farm got affected, population unrest is higher=> bad and their army outmatch mine in terms of head count and eliteness!

After many many tries over the weekends playing the game, got wipe out then restarting game, experimenting with the opening strategy to outlast my overload. I think i got one of the effective "opening strategies".

At 1st turn. offer 20 turns or more of military access to neighbour such as saito and kiso for gold. the more the merrier. I got about 4000 gold for 20turns or 6000 gold for infinite turns. Offer to trade with both of the too, this will generate some income. While still a vassal, let other factions that border you pass your land for a fee. This will generate lots of income. Offer to marry Saito's ugly-greedy-evil-bitch daughter at 120gold (hey, i got 4000 from previous remember?). Straight away the relationship became "very friendly". By doing this , Saito will take Oda (hostile with each other) sooner and defuses the enemy marching on my land and later shadow me from the north against Hattori. With the newly acquired gold, i ordered my metsuke to bribe the oda clan's army that is on my land with 35% chance. A successful acquisition would cost me 3670 with 1unit of yari samurai and couple of the ashigaru units. Next, order my daimyo to attack the remaining Oda force to earn some bad-ass reputation (i always groom my generals to be the level of "intimidating", good for maintaining peace on newly acquired land.). Now the enemy retreated, I had a choice of pursuit Oda at Omi (very fertile land) or not. The fact is, with my current army I have a less than 50% chance of winning. Got to give it to Saito. Research on "chi arts", with the focus of getting my kishio ninja ASAP. These are the featured units for Tokugawa clan. Destroy the "rice exchange", so that the sake den could be build at the next turn. Build the farm land+1 upgrade to sustain the clan. Remaining amount of gold, recruit ashigaru archers but bear in mind the upkeep should not exit the next turn income. Hit next turn.

Turn 2-4. Build sake den. Train more arches. Research chi-arts to get my kishio ninja. Build trading port and start to send ships to explore for new commodities. Bear in mind, the army/navy maintain cannot be more than the next turn income.

Turn >4. Upgrade the sake den all the way till criminal syndicate. Behold, my Kishio Ninja. They are expensive tho. 884 for recruiting and 295 for upkeep. By now, Oda should be wipe out by Saito and Hatori is on the rise. Rule of thumb, try to save more gold for rainy days.

Turn 45. Hojo declare war on Imagawa, my overload. By now, i have some gold at about 2k, an army that could defend my castle and several ninja and metsuke. Here comes the intriguing part. I want to hold Izu the gold producing land held by Hojo and it's kinda far away. I want it so badly i would use my ninja to sabotage imagawa's marching army to delay it by 1 turn so that i could take Izu. But the bad thing is, Hattori would border/siege my castle to the west because Saito gave in to early. Eventually Takeda will then border Izu and overwhelm my castle with their elite calvary. Build a temple too, and the monks recruited could be use to cite unrests in rival land. The rebels will eventually overpower the owner and own the land and thus I would attack the rebels. Good way of taking their land without inciting war.

The AI in shogun2 is AWESOME, almost 50+ game restarts with different strategies i experienced different game play and still end up loosing at 70+ turn.

The only time i played until 100+ turn was I did not participate in the war against Hojo and my overload was killed, freeing me from my vassal status. With my monk+mesuke+ninja strategy i took many lands and maintained a chummy relationship with the owner which I took the land from. Awesome isn't it. Things went south when my favourite general Iyeyasu (historically, he created the tokugawa shogunate that runs for 265 years) and the next inline to be daimyo got sandwiched by Hatano, Asai and Kitabake while retreating to the nearest castle. Just a few more inches and he will be safe. Because playing at Legendary difficulty, i could not do a quick save nor a reload, I can't turn back time. Sounds like life huh?? After many set backs i resort to manually copy the save game file to create a "backup" which I found out later.

If you are interested to pick up from where I left with, here is the game saved at turn 45.
http://db.tt/5JD5ZfvS
paste it in the saves_game folder at C:\Users\"username"\AppData\Roaming\The Creative Assembly\Shogun2\save_games

share with me your strategies too~!

[Arduino] water sensor

2011-11-01T16:15:00.000+08:00

I was tinkering with the idea of water sensing with arduino. The rain sensor / water sensing kit/ water detector/ is kind of hard to come by from the Internet stores. Courtesy of Mr.ChongSP, I get to sample his water detector PCB.
Thanks!
The concept of working is the gap between the PCB routes will close when there is a water droplet run across it. Water conducts electricity. With the appropriate pull up resistor connected with the PCB kit as per the diagram below, we could get the components up within minutes.
Quickly I hook it up with my arduino and used the "button" sample code. i.e the switch button is now my water detector. If there is water, light up the LED, and if there is none off the led......

Now, here comes the interesting part.
1. instead of the usual project of "detect rain-retrieve-laundry" type of application, can we have something more interesting????? I have at least one in mind... hehe
2. is there a way i could do away with the PCB water detector, it looks kinda out of reach to me. Sure! how about using double row male PCB header?? hehe

[Arduino] Bi-Directional DC Motor Control With Arduino Only.

2011-10-10T16:54:00.000+08:00

This is probably not the best way to get it done. Nonetheless, we could use Arduino Digital I/O pins configured for PWM to control a small little motor that is meant for solar use. The reason being, the current requirement for solar motors are much lower compared to tamiya motors etc etc at the toy scale.
The risk of frying the Arduino is much lower, but doesn't mean that it will not fry the arduino!

BEWARE of the risk involved as I am not responsible for your own doings.

Programming it is pretty straightforward but with a little twist on the understanding of PWM. Standard PWM outputs are used to the DC motor. If both PWM are arrive timely and "synchronized" i.e LHS is logic low and RHS logic high, the SMALL DC motor would see a complete circuit all the time. The small DC motor is tricked on seeing a +5v applied to RHS and gnd at LHS. To reverse the rotation from CCW to CW or vice-versa, just reverse the PWM outputs.

The goodness of having PWM output to the DC motor, the rotations could be control instead of just rotating at constant speed. Giving the users acceleration if needed instead of just velocity.

Now the mind boggling part. How to use the limited number of PWMs on arduino to control 2 small DC motors effectively ?? Try it but at your own risk!!

enjoy the 1 side motor

code here

[Arduino] Bi-Directional DC Motor Control

2011-10-10T16:33:00.002+08:00

[Arduino] Bi-Directional DC Motor Control
As time to come, we need to control motor or maybe even motors using our arduino. The 40mA limitations on the arduino Digital I/O pins made the load for the projects somewhat limited to LEDs and small little motors meant for solar (mainly because these motors are low in current requirements). What if I want to control big motors and really BIG A$$ motors?

For tamiya motors (3~6v, <1A), I would recommend something such as the ArduMotor shield available from sparkfun at the cost of USD$25.50 (retired from sales) or the MShield from adafruit at the cost of USD$19.50. I do have the luxury of using the earlier, add a heatsink with some thermal paste and run at 2A max per channel continuously before one of the wheel got stuck and fried one side of the shield. For really BIG A$$ motors at the range of 24V 10A, I used Sabertooth2x25 available from Dimension Engineering at the cost of USD124.99.

The issues with buying items from the Internet and to ship from US, the turn around time is toolong (or short at the expenses of the consumer), and vendors locally do not carry it in-stock. For simple motor driver circuits, it is just a L298 chip (or couple with L297 for stepper motor control) with the accompanying circuit. The real hassle is to wire it up on stripboard and solder it. Which deter many from getting it done.

I chance upon Mr.ChongSP’s D&I lab previously. Apart for the SSR kit, I also asked for the Bi-Directional DC motor control kit, which was meant for the PIC18 MCU sets. Thanks Mr.ChongSP!
pretty neat huh.

After soldering up the components, it is time to wire up the tamiya DC motors to the motor controller to the arduino. Making the ribbon cable connector break out cable is such a chore and demanding on the eyesight. Luckily I got student junhan to help me on it.
Attach the power source. +5v to the motor control (VSS) and >5v for the motors (VS).

Upload the code to Arduino and waiting for the magical moment...... after 2mins... still no sound, no noise and the motor control L298 is totally cool to touch. Something is very wrong here. Check connection, check code, check corresponding pin on motor control board to arduino and to code , just in case there is a mix up. No fault found. A quick check using the Digital Multimeter, only 0.2V measured across the DC motors. Seems to be dry cells I am using the current is not enough to drive the tamiya dc motors. Thus I swap to a 8.4v 200mAh GP rechargeable, only 1 side of the motor is driving. LOLx

A quick swap to conventional DC motors
Pheww... it worked

Time to source for some LiPO cells to play with my tamiya motors setup with the Bi-Dir Motor control board!

source code with comments here

[Arduino] Solid State Relay ( SSR )

2011-10-07T16:02:00.001+08:00

[Arduino] Solid State Relay ( SSR )

Currently the DIY PRT prototype uses a HUMANGOUS 24V 10A mechanical relay + transistor circuit to switch between the 5V MCU digital pin and the 24V 10A DC supply to the motors.

In the next step of modularizing the building blocks of the DIY PRT into an Arduino Shield, that AWESOME relay could not fit into the shield. Worst part of it, the EM generated by the motors traversed the wirings and this affect the reading of the sensors. Previously, sparks was observed in the mechanical relay when the circuit turned on while the wheels were locked accidentally. If working in enclosed environment with dangerous gases (not fart pls), the spark might cause an explosion...Worst of it, there is no isolation of high current high voltage circuitry from the low voltage low current MCU. The circuit run a risk of frying the components at the low voltage low current side. Well, unless the opto-isolation circuit (opto-coupler) is included. The circuit get more and more complicated with each additional feature added!

The challenge here is to reduce the size of the relay, have opto-isolation and also simplify the circuit. SSR is here to the rescue~~~ http://en.wikipedia.org/wiki/Solid_state_relay
_________________________________________________________________________
One day while running some errands outside the office, I chance upon a SSR circuit from Mr.ChongSP’s D&I lab. It was displayed outside the lab.

Using my thick-skin-jutsu i approached the lab TSO and executed my BBS move on her. Mr.ChongSP and TSO Ms.Jana were more than happy to supply me a set of the SSR kit. thx! Look at the timestamp of the pictures, It took me more than a month to acquire, experiment and write down the experiment. Time is a rare commodity (exam, marking, checking, tallying, data entry, checking again)….If you have some spare CPU cycles, consider to supply me some.
The TSO reminded me that this PCB connection is meant for DC-DC switching from low voltage to not so high voltage. But according to the specsheet of the omron SSR (I love omron relays!) http://www.omron.com/ecb/products/pdf/G3VM_351BE.pdf
This babe is capable of switching to 280V 100mA !!! Just to be safe, I only try to turn on a LED. lol. A quick peek at the specsheet, this babe is capable of switching DC-DC and also DC-AC depending on the configuration.
Soldering the PCB is pretty straight forward with the detail explanation on the silk screen. A point to note, when soldering ICs’ , never mount the IC to the IC holder while soldering the IC holder to the PCB. The heat form the solder might damaged the IC. An advise from my lab TSO many many years back when I was a student here. IMMA such a good student @@”
Only plug in the SSR when all the soldering is done.

Pretty neat huh...

Now, connect the GND pin from the PCB to GND pin on Arduino (I found some students make this mistake when wiring up stuffs... The consequences may range from very small such as circuit not working to very serious such as sparks and fried MCU), VCC pin to 5V on Arduino and lastly signal pin to any one of the digital output pins on the arduino.

As for the code, I use the example code found at File->Example->Digital->Blink.
The SSR will be triggered at specific interval, turning on the LED. Phew.... everything work at 1st try. Now, time to wire this SSR to more interesting hardware (<10 V load plssss). Interested to play with it ????? dXD

[Java] Credit Card validity checker using Luhn and known MII

2011-08-16T12:26:00.001+08:00

I received an email from Mr.Chua yesterday seeking help on behalf of "dignitykitchen" to address the matter on
1. whether there is a way to differentiate the various credit/debit cards eg. AMEX, VISA, DINNERS etc?
2. Is it possible to read the card to get the card number and tell the type of card?

Suddenly the thought of using this as a case study for Java programming I assignment crossed my mind.

Nonetheless, I could not wait till next semester to start to code and quickly hack up a POC using Java for Mr.Chua. Usually, I code in C++ or python, since we are going to learn Java Programming I soon therefore I shall code more often in Java. The implementation can be ported on C, C++, Java, python, android, arduino (to hook up with a magnetic card reader, more later) etc. As long as the programming "logic" is sound, it can be demonstrated using different language. It is analogous to saying "I love you" in different language..... You get the idea.

The code uses luhn algorithm to check the validity of the credit card number, through a series of steps on choosing alternate number starting from the LSB, perform calculation and finally a MOD10 . The code does NOT check the validity of the card with the credit provider. Features such as manual input, identifying credit card provider were added. The code base can be expanded to recognize more info from the number itself.

Apparently I misinterpreted the word "read" from the email received, after realizing it from another colleague's suggestion on using magnetic card reader with an MCU to "read" in the data from the card and do the validation checks on the MCU iteself. Anyway, the validation code can be ported to the said MCU... e.g Arduino with a magnetic card reader.

NOTE: Source code is for academic use only.

1. place Main.Java and LuhnCheck.java in the same folder. Compile (I did it using javac) and run.

Main.java

Luhn.java

there goes my lunch time...... duhz.....

[DIY] Arduino VU Spectrum Analyzer

2011-07-08T18:00:00.000+08:00

While searching on the Internet on interesting way of approaching the purpose of doing Fourier transform and why we need FT for my teaching.

I came across a fellow arduino user (http://andydoro.com/vulol/) that posted his toy project on using Fast Fourier Transform (FFT) to make a VU meter. Couple of years back, I did played with my home made wireless VU using electronic components that is available from the store. I am quite surprised that an 8bit Arduino is capable of doing FFT, never did I thought of using it because usually I am using a PIC32dsp for transforming from time domain to frequency domain for signal manipulation purposes. Arduino did gave me the WOW moment for a while.

From the detailed explanations on his website , i downloaded his code and hook up my LOLshield on my laptop playing some song to enjoy the geekness of arduino LOL shield VU meter.... To my dismay, it doesn't work "out of the box". It just display a 1 liner.... both plug in to my laptop and plug out from my laptop. Seems that the VU only picking up white noise from the ambiance. The connections are correct, pin A5 for +ve signal from the left channel and ground to common ground of the mini stereo jack.

To further complicate the issues, I tried on a variety of input of devices ranging from my android phone, my speakers with a BIG ASS amp etc. Suddenly IT hit me, probably the analog signal read in at pin A5 is too low to be detected as a usable base band signal where the FFT would chop up the signal in time domain to be put into frequency domain and the harmonics combined as 14 outputs (LOL shield only have 14 columns of LED).

There are 2 ways to put the analog in on steroids. The hardware method, I would use a TIP31C or TIP41C audio amplifying circuit OR the software method by scaling up the data read in on A5. I choose the software method, it requires little time to prove my hypotheses compared to the hardware method.....

It is kind of worrying.... the VU is more sensitive now ,picking up ambiance noise which is reflected in the below picture. The LEDs are lighting up ....More work needed to change part of the code to filter AWGN....

But once I plug the mini stereo jack to a Y connector with the headphone stereo jack into my laptop, the noise signal disappear.
Played one of my favorite songs with rich sound texture... Sorry for poor sound quality... I am playing it through my headphone.... still office hour and I can't turn on the LOUD music...

enjoy the code. you would need to place the FFT and charlieplexing libraries in your arduino\lib\ folder to compile successfully.

BGP awesomeness with Packet Tracer 5.3.2

2011-06-18T17:48:00.001+08:00

With Packet Tracer 5.3.2 you can experiment with BGP (eBGP)

It serves as a good tool for a refresher, especially for poor chap like without exclusive access to the cisco racks....

Here I demo Cross AS BGP. Not all the BGP peers have a direct peering. I use the "network" command to do the routing.

Common mistakes that might occur
1. Peering with BGP peer on the wrong AS
2. Peering with BGP peer on the wrong IP subnet
3. Configure wrong AS for BGP on the victim router
4. and the list go on....

to verify your settings...
sh ip bgp

sh ip bgp neigh

come code for your reference.....

my first attempt: solar cooker

2011-06-15T22:15:00.000+08:00

Get a BIG cardboard, some aluminium foil and adhesive.
1 black or dark colored cooking vessel.
1 small piece of wood as insulator.
1 clear plastic bag. I got mine from the fresh fruits section at NTUC... but realise it was a lil too small to fit the flower pot I am going to use.

We are going to form a cone shape with the cardboard, hence make a cut with a diameter of 25cm or more to accommodate it. Paste the foil on the cardboard, shinny side up. I made a mistake of inverting it....oh well...

I was hunting for a pot like apparatus to secure my new toy... Went hunting around and discover some flower pots......

weather check.... it was cloudy.... not a good day for solar cooking....

I am experimenting whether solar cooking rice or sweet potato will be edible? Typical Asian staple.

Just in case you guys wondered where did the flower pot went to ...

Cooking time -> 1245 - 430pm...
the plastic bag burst....

Conclusion.....
The rice is not cooked..... but the rice water is warmer then room temperature.
The sweet potato is not cooked thoroughly. Never buy $1 sweet potato from NTUC... rotten ...

next up.... improvised on
a. neater foil reflector will lesser creases when pasting it to cardbord.
1. weather check appratus..
2. temperature check apparatus....
3. quantify the heat generated from this solar cooker.. (a lil far fetched)

kit set amp for old Sony speakers

2011-05-19T23:20:00.000+08:00

So there were 2 VERY OLD, DUSTY (at least 1" thick beneath the cover!!) and UNAPPRECIATED Sony speakers that one day magically appeared in our T902 club hauZ. Seems that somebody conveniently let this GOOD SPEAKERS rot in an isolated corner, get kick around and UNLOVED.

Upon close inspection, the speakers are still usable. Well, at least the leads to the + and - terminal are still intact and no sign of corrosion from the moisture yet. To make these bad boys start to sing angelic tunes AGAIN, I need something to amplify the audio signal from iPod, laptop, android phones etc (not necessary be mine laaaaa). By plainly hooking the other exposed end of the mini stereo jack to the speaker’s 2 terminal won’t yield any sound. Better luck if the speakers are hooked up to a 2kHz function generator.

I need an AMP as cheap as possible. There is no luck finding the original Sony ones. Obviously, it was dumped because of the spoilt amp and hifi system. Try making one amplifying circuit from components from the lab, e.g some TIP31C, R&C ? Too time consuming and the amplified signal produced may only yield <1W from these big ASS speakers. We need something that can yield 8W from the circuit. A quick look at the store, no such IC’s readily available.....Some shopping is seriously needed at your friendly Sim Lim Tower.........After some browsing at the kit set’s section, I came across a 8W amplifying circuit kit set complete with good quality PCB with routes thick enough to pass high current, BIG heat sink and the best part, it is only s$17.50. After laying my paws on it, I hurried back to office can’t wait to start work on it.

The I/O parts are not supplied in the package, just few pieces of measly bare copper connector. I modified the inputs to a 3.5mm Stereo jack for the convenience's sake of plug to a laptop/android/iPod etc. As if it is going to be the headphone, albeit a BIG one. As for the power jack, it is done using a DC power jack with the +ve leads in the inner ring. DO NOT SOLDER or CONNECT inversely ! Outputs, I used some screw down terminal blocks meant for PCB. Too bad the PCB is designed for the above mentioned copper. I got to cut the terminal blocks to half to use it. Make sure to stick some tape on the components side, this is to prevent the components from falling out of place when soldering.

Fire up the soldering gun and start soldering......

Next up, I need a power supply that can supply 12V DC for 1A. My unloved HP charger can only go up to 6v and 200mA. I quick dive into my pile of junk and tadahhhhh... I found a dc wall adapter that satisfy the requirement. Lesson learnt, do not discard the old parts. It may come handy some day. I also added my VU meter which i made many years for practising my soldering skill. Now we got LED light indicators on the sound

Hook up the dc adapter, stereo jack to laptop and speakers to the amp circuit. Enjoy!
On a side note, the boys hook up this set to their home made projector and now we got a poor man’s cinema complete with “dolby digital surround” (speakers on the floor facing wall and reflectors to create the effects)!

What's neXt? Tube Amplifiers ???? teeeheeeheeeee

exercise code

2011-02-08T09:41:00.000+08:00

refer to your year1 structure programming book

1. pg 121 . create a new function that calculates the difference of 2 numbers

2a. pg 146. modify the code to use a vector instead of an array.
2.b. pass by reference the vector to a new function to add 5 into each elements of the vector. Cout the vector in the main() to verify the value.

[DSA] binary tree

2011-01-25T08:02:00.002+08:00

terminology
the root: the beginning of a tree.

every node is possibly the root node for the nodes below it. eg. the parent node.

parent node, the n-1 lvl of the n's lvl node.
child node, the n+1 lvl of the n's lvl node.

(n-1)
|
___n____
| |
(n+1) (n+1)

edge, the path for traversal to happend.
leaves, the lowest lvl in the tree.

a binary tree, a tree where each parent node only have 2 children.

binary search tree (BST)

a binary tree, where the root node is always the middle value of the list of values.

remember binary search from previous week?
what are the 2 possible condition to be satisfied before one can qualify for binary search?

BST it self is not efficient. there is a possibility that the insertion of the node will cause it to behave like a worst case binary tree.

we need a sorted BST, where each time a node is inserted the tree is "sorted" to find out which is the new node. What are the implications if the tree are always sorted when insertion or deletion is done??? Is there any other possible way to enhance it?

3 ways for tree traversal
-Inorder
Traverse the left subtree
Visit the current parent
Traverse the right subtree

-Preorder
Visit the current parent
Traverse the left subtree
Traverse the right subtree

-Postorder
Traverse the left subtree
Traverse the right subtree
Visit the current parent

uses of binary tree data structure
- compression
- encoding
- conversion of mathematical formula to prefix or post fix form
- data structure of choice for "fast" retrieval of search items

there are many other type of binary tree
full binary tree
perfect binary tree
balanced binary tree
self balancing binary tree

[DSA] map and set container

2011-01-24T09:55:00.002+08:00

map<string,int> mapp;
map<string,int>::iterator mit;
string name_search;

    mapp.insert(map<string,int>::value_type("Amy",81377442));
    mapp.insert(map<string,int>::value_type("Bob",32731631));
    mapp.insert(map<string,int>::value_type("Catherine",32387163));
    mapp.insert(map<string,int>::value_type("Danny",21321312));
    mapp.insert(map<string,int>::value_type("Ecuador",54543947));
    mapp.insert(map<string,int>::value_type("Felicia",32535612));
    mapp.insert(map<string,int>::value_type("Genie",24172312));

refer to above on how the map data structure is used.

use the map data structure to satisfy the following requirements.
1. create a phone book application that can store name and phone number.
1a. perform a display all entry in the phone book.
2. phone number need to that ensure it is 8 numerical digits only.
3. initialize the phone book application with some data.
4. perform a lookup for a random entry in the phone book and display it.

challenge
5. Suggest a method to store address, email and msn address to the phone book that you have already created.
6. what are the advantages and disadvantages of your method??? explain why you choose the design.

[DSA] searching

2011-01-18T07:57:00.001+08:00

Have you ever tried to find something in your house/room. Yet can't seems to ever find it. Now, lets not talk about misplacing items out of carelessness. Let's discuss how to "find" items in your wardrobe.

Assume you have your apparels hanging in the wardrobe, how would you "find" your favorite shirt/dress? would you start looking from the left hand side? the right hand side or simply in the middle???

If you find 1 apparel at a time from either direction, that is linear search. The worst case scenario is, you would traverse all your apparels before finding your favourite.

If you have sorted your apparels according to a certain sequence, eg, warm colours to the right and cold colours to the left, you can simply start finding from the middle, then to the left if your favourite falls in the cold colour. This is binary search. searching time can be reduced significantly.

Again, if you do like what i did, simply pile up all my apparels in the wardrobe without sorting/folding/ironing it. "Finding" for a particular item in the wardrobe can be disastrous.

Linear Search => O(N)

Go through the entire array of items to lookup on the searched key. The sequence of items are not sorted.

Best case , the 1st item in the array.

Worst case, the last item in the array.

Average case, traverse for half of the array

Binary Search => O(logN)

Uses a divide and conquer method.

array of items must be sorted first, involves a cost.

L <> root

|---|---|

L---M---R

For any array of 1000000 items, Linear search need 500000 comparison (assume an average case), Binary Search 20 comparison.

Pop Quiz

1. Create a generic code of linear search to take in different data type.

2. Create a Binary Search tht uses recursive method.

3. Use find() or search() from the STL to do a lookup of a string, among many strings stored in the memory

[DSA] Sorting

2011-01-17T10:33:00.004+08:00

Here comes the interesting part in algorithms.

Sorting and searching are the crowns in the algorithm topic. So to speak, these are hottt topics for research in computer science world.

Efficiency, cost. Remember???

We will be examining bubble sort, insertion sort, selection sort and merge sort in details. Studying the complexity of the above algorithms, and not forgetting the implementation of the algorithm. Both DIY code and STL.

But Why Bother to Sort?

Here comes the question>>>>>>>>>

1. Implement sort descending for Bubble Sort, Selection Sort, Insertion Sort, STL sort. Use int arrays or vectors to try it out.

2. In our session, we use integer to demonstrate sorting. Is it possible to sort characters, strings, double, objects etc? Use vector or arrays to try it out.

3. Use the sorting algorithm of your choice, sort 10 tropical fruits of your choice.

4. On top of the previous implementation, create a class for fruits with 2 parameter namely int price and string fruitName. Sort the 10 tropical fruits according to fruit name or price. Your implementation should be able to sort both price and fruitName ASC or DESC. A menu might help in here.

5. Lastly, what considerations when we need to ponder when comparing 2 arbitrary Sort Algo A and Sort Algo B. How would we really know that A is better then B ?

There might be more then one implementation of the above sorting algorithm. Below are my flavor for the 3 algorithm. Codes are commented for easy following.

//bubble sort

//insertion sort

//selection sort

//merge sort

[DSA] Queue

2011-01-11T08:58:00.002+08:00

Long time ago when i was still working in shenton way...

I need to wear shirt+neck tie+business slack. If there is a need to meet then client, add another blazer under the blazing sun. It rhythms rite~

Geek like me, I find matching colour of my outfits seem to take forever to learn. There is no hard and fast rule. Best, it is very subjective. Different people will give you different preference and a piece of their mind. ARGHzzzzz. How nice if (day=monday){setBlue();} can be applied to matching my attire.

So to play safe, I bought seven sets of outfit that the colour would match generally. Hang them in my wardrobe from left to right for monday to sunday (I work 8 days per week). I applied FIFO (first in first out) on my "queue" of attire. hehe. Because, I always take from my LHS (Left Hand Side) every morning for my business, and replenish at the RHS after it is done from the laundry.

To hide the fact that i am lazy to choose my attire, and there is a high probability I would wear the same thing for that day of the week for all the weeks in a year. I did a one left shift on my "Queue". Then my wardrobe queue would behave like a barrel shift register that shifts by one bit. Hence my algorithm would keep me safe from the optic blasts of the "fashion police". Sad to say, I still did not escape the scrutiny of the fashionista.

There is this girl in my office, which takes a mental note on the pattern of the occurrence of my attire. She observed my algorithm for about 3 weeks then I am busted.... No, she did not became my wife.

Drill Questions

1. Create a queue of 10 items, of your choice.

2. Assume that the 4th item in the queue is of higher priority, retrieve it first.

3. display the remaining items in the queue.

HEROES ONLY!

4. Create a queue of objects. Each object have a different priority 1-10. 1 is highest priority, 10 otherwise. Object with the highest priority in the Queue need to be service first.

5. Based on 4, create objects at random interval of 1s to 10s and enqueue them. You can assume that the queue is dequeue at every 1 second

6. In the emergency ward, some cases are more serious then the other. Assume there is more then 1 queue is available. Suggest a method that would give Queue tickets to non-priority case, while ensuring life threatening case get service accordingly.

[DSA] stack

2011-01-10T09:49:00.001+08:00

Stack, a last in first out (LIFO) type of data structure.

very similar to our STL list learned last week, there is also a STL stack.

|a|

|b|

|c|

Long long long time ago when i was still a student and still staying in the hall (Now I am still a student, constantly learning new things!). My friends always asked me why i always wear the same t-shirt from monday to sunday. Being the computer science student, I try to explain to them the reason using the stack data structure. Every time my laundry is done, it is folded nicely (assume please) into a stack. When I fold my t-shirt, and placed them in a stack. I fold them in the same order for every week and always take from the top of the stack of tshirts so that my wardrobe will not be messy(assume it is not messy).

Talking about needing randomization in folding t-shirt and putting them on a stack. Every morning wake up, I am always in a rush. So, I always choose the first t-shirt (the top in stack data structure) of the stack. The cycle repeats it self again and again. Sometimes, I do accidentally pull a tshirt out of the middle of the stack and the stack of tshirt just collapsed. Things got better when I found another person to fold my laundry when I was staying in hall!

Stack is efficient, minimal disturbance to the memory when data is inserted/deleted because only the top of the stack is modified. But when the 5th element of a 10element in a stack need to be retrieve, there is a lot of manual code needed for manipulation. Hence the efficiency and performance of the stack data structure is not satisfied.

So......what to do with the stack data structure? It can be used to store the dungeon level information. How many of you have played the game dungeons and dragons?? The assumption is that player can only go to 1 level above or 1 level below the current level of dungeon. Hence, using a stack to store is more sensible. Of course, a list can be used too. But... what are the consequences????

Have you wondered how the mouse in the micro-mouse competition know how to escape from the maze??? All movements of the mouse, eg forward, backward, left, right are stored onto the stack. When a dead end is encountered, the mouse will take a step back by simply pop off the top item on the stack. This is for navigation that requires a step back look left/right algorithm.

Other uses of stack, is in the operating system, where the system variable is stored. The stack is used to hold temporary variable of an executing program. Another stack is used to store the starting address of programs. What happens when the stack used to store variable is "overflow" ????

Drill question for the week,

1. Create a stack of 10 items.

2. retrieve the 5th item on the stack.

3. display the remaining item on the stack.

4. Modify week 4's decimal to binary conversion program and implement with stack.

4. Modify week 5's palindrome checking program and implement with stack.

SPINNOVEX 2011

2011-01-06T20:06:00.000+08:00

we are featured on the channel 8 news (1:05 to 1:40)~~~

35sec of precious air time~

[DSA] Linked List

2011-01-03T09:39:00.002+08:00

Linked List (LL)

Let assume today is your first day in school and your are appointed as the class rep. Most likely the first task you and need to do is to write down the names and contact information of your class mates.

But how are you going to do it??? Do you randomly scribble the information on some paper napkins and shoved it into your bag? Or write down the names and contact information one by one, in a list form? Or fired up your web browser and point to docs.google.com and start making a spreadsheet?

The data you have entered is unsorted, so this tiny piece of paper/document serves as your lookup table when you need to retrieve some information. E.g your classmate's phone number

This week, we are going to explore the several api calls to use STL list to insert data, manipulate data and to retrieve data.

Say you want to find out your new classmate catherine for her phone number. How would you look for the information in the list? Most of us would look from top to bottom, some bottom to up, some start in the middle and traverse up or down. Inherently, you still lookup the information from the list one by one. All this methods to find her name doesn't really matter, because the list of information is unsorted, it will still take n+1 effort . The effort to lookup a name in the list gets bigger when the list grow longer and longer.

In the list of names you have,how would you input new names for student that just got into your class? Do you add it at the end of the list? Or simply insert the name to any position where the space permits?

All the above is the analogy for the Linked List used in the computer

Items that is stored in Linked List have to be travsersed sequentially. There are no random access iterators to access link list. Hence, you need to declare an iterator of the same data type that is used by the STL list container.

When you are designing the code and you needed data to be access randomly, Linked list is not the best option. Traversing the whole list of items takes time. The time required will grow accordingly to the size of the list. So, vectors or arrays are the best option (at the moment of learning). The items in vectors and arrays are placed side by side in memory world and can be access in a random fashion.

Items of a Linked List are not required to be placed side by side in the memory of the computer. How items are "linked" in a link list are done by the maintaiannce of the "header" pointer and the "tail" pointer. Pointers, as we have learned in the previous sessions, are variables that store the memory address of the items we are interested with. The tail pointer of the current items contains the address of the next item, ie. the value stored in the head poiter.

0->hP|DATA1|tP->hP|DATA2|tP->hP|DATA3|tP->0

Changing the values of the pointer variable requires only O(1) effort. Hence, the linked list is efficient when data/items are required to be inserted randomly in the list.

If the deletion of an item is required in the linked list. All need to be done is to modify the tail pointer of the current item, skipping the item we want to delete and points to the head pointer of the item next to the deleted item. In other words, we are merely copying the address in the tail pointer of the deleted item to the previous item's tail pointer. cool huh. No more holes left in the memory, no more statically declared memory that is left unsed, no more ugly algorithm to compact the array after a deletion of items.

All the above, are naked to the untrained eye. Users can't see the differences, only the programmer does.

DRill Questions:
1. create a list to store name of your classmates.
2. print out class list
3. "find" a particular person in the list. return found or not found.
4. Find out a method to attach the gpa score to the names in the list above.
hint: use class and OOP.
5. sort the list by gpa descending.
hint, try out stl algorithm

New Year Resolution

2011-01-02T03:27:00.000+08:00

It is once again, the same period of time to do some self reflection on what I have did in 2010 and what I want to achieve in 2011.

Remember my words?? I am only worth how much I promised.....

let's recall what I promised to do in 2010.
~~1. drop 2kg per month~~ I did not lose weight, instead i gained weight. Please call me dot1tonner (for) now~
~~2. participate in standard charted marathon~~ I did not run in standard charted marathon. Lazy duhzzz
3. eat KFC, every saturday and sunday dinner
4. eat Macdonalds, yessss!! almost everyday especially it is so convenient.It is right below my office!
5. ~~go to the gym~~. erm, only step in once last year, the day before I do my annual med check up.
6. ~~run 10km every saturday.~~ nope was enjoying my beauty sleep till late evening.

the conclusion, I self pwned. None of my fitness goal is achieved.

As I mentioned last year

When it comes to setting goals, be very sure the goals set are "SMART"

S= Specific / Simplified / Strategic
M= Measurable / Manageable / Money ?!
A= Achievable / Attainable / Agarlogic?!
R= Realistic / Relevant
T= Timely / Track-able / Traceable

What is missing from the above, is the how to's to achieve your goal. More importantly, a schedule on what to do that you can follow closely to achieve your goal. Since i did not paste on my wall my workout schedule as big as loan shark ah long's, hence, nothing is tracked closely and finally nothing happened.

It is once again, the same period of time to do some self reflection on what I have did in 2010 and what I want to achieve in 2011

Now, lets do a flash back what I have done in 2010 (instead of the ones I did not do)......
1. ~~spent many late nights in the labs (FYP, WSS).~~ Checked. (Actually I lost count how many nights)
2. ~~spent many Saturdays and Sunday in the office, lab.~~ Checked. (I have access to 2x labs! 24x7 yeay~)
3. ~~study for certification.~~ Checked. 1x CCNA-S, 1x CCAI, 1x CCNP3, 1xCCNP2, failed 1xCCNP1
4. ~~pickup new programming language~~. Checked. Android, Arduino and Processing.(In the process I mentored 2x group for android competition)
5. ~~deliver 1x segway like robot for student FYP~~. Checked. Delivered 4x instead, with different variations. FYP roxxxx~! It is fun to be part of the action. The anger, the sorrow, the mourning, the delight and the adrenalin rush. It was a roller coaster ride, I hope you guys that rode with me enjoyed the process and learn how to manage tech, people and team work. This item drawn most of my energy, but it is worth every single Joules!
6. ~~coach trainees for final round~~. Checked. They got 1x GOLD medal in the process of preparation. It is very hard to manage disappointment, because not all manage to get through. But, I have to move on instead of swimming in alcohol to pacify the sorrows.
7. ~~Annual leave of 56days~~. Checked. I am still finding ways to use them... duhzzzz
8. ~~receive a medal of some sort~~. Checked. I got the Commendation award for E-learning in EETC10
9. ~~look out for postgrad / phd lobang~~. Checked. None came to my favour. It is hard on me, especially got rejected twice in a row. The feeling is worst then getting rejected by my first love(let's assume I had one).
10. Treat myself nicely?? LOL...I just had to make it a 10, since it is for 2010.

nonetheless, I applied SMART goal method to achieve it. You can do it too!

I have been especially harsh on me in my own capacity and this "aura" of my RDF (Reality Distortion Field) affects the boys and girls that worked for me directly. They draw the flak most of the time and yet they survived it. It was unintentional, BUT I really want you people to buck up and start to prioritized the designated task upon others.

Now, my 2011 goals which I am going to use the SMART goal method to align it.
1. only eat 1x meat and 2x vegetables for lunch EVERYDAY
2. only eat KFC (and only 1pcs of original breast meat) for dinner once per week.
3. say NO to macdonalds extra value meal with upsize. (only 1 double cheese burger per week)
4. burn 600cal every wednesday in the gym.
5. use my 56days annual leave

[FYP] finishing touches on type II and type III

2010-12-31T10:22:00.000+08:00

happy new year~

type III

type II

[FYP] TYPEIII prototype

2010-12-20T08:55:00.001+08:00

mobile chair like self balancing device that is capable of moving one person.

uses
arduino UNO as the MCU
IMU
flexiforce sensors for maneuvering
wheel chair hub motors.

[DSA] General Maths Algo

2010-11-23T07:52:00.001+08:00

Long long long time ago.....
Programs are written in C++ to solve mathematical problem, not much of user click here and there on the GUI. Mathematical problem can range from calculating relative distance, trajectory etc.

To make life simple, there was "math.h" in C(include math in c++) to help make the calculation. "math.h" alone might not be sufficient to cover each and every possible scenario, hence some programmer do have their custom class to do the math related to their program.

We have studied general maths routine such as converting from decimal to binary (d2b) and at least 2 method to calculate Greatest Common Divisor(GCD). Through the d2b function, we learned how to decompose the "steps" to get the binary from the decimal and translate the "steps" it into code.

The direct application of the GCD I could thought of is the computation of the public key and private key pairs in the RSA algorithm (http://en.wikipedia.org/wiki/RSA). Encryption is as simple as calling a function (java and C++ have the library), but behind the function call, these are the necessary code to calculate the key pairs.

Notice there are 2 possible way of programming the GCD, through the recursive method or the iterative method which we have discussed previously. Is it easier to understand the recursive code then the iterative code???

Below are the questions for the week.
IP address in the form of A.B.C.D, where each octet A,B,C,D range from 0 to 255 in decimal.
1. How many bits each octet hold?
2. What are the "steps" required to convert one octet to binary?
3. Write the function that would convert the IP and gives it equivalence in binary.

note: you could modify from the d2b function, or propose a simpler algorithm based on the characteristic of the IP address's octet

[DSA] Iteration and recursion

2010-11-22T08:17:00.001+08:00

Look into the mirror and observe your self. Look into your eyes, you will notice that in your pupil (the dark/blue/green color portion of the eye if you are asian/Caucasian) you can see yourself in it. Now, look into that pupil on the mirror. You will observe yourself again, albeit a scaled version. That is what i call recursion, you will see yourself again and again in your pupil.

Assume that you can see even the smallest detail of yourself through the mirror, notice that there is no end to the vision?

This is not good for recursion in computer science/programming. The program keeps executing recursively, until the system resources run out. So, at least a condition for the recursion to stop must be defined, which what we called the base case.

Anything that is solved iteratively, can be solved recursively.

Fibonacci The first number of the sequence is 0, the second number is 1, and each subsequent number is equal to the sum of the previous two numbers of the sequence itself. Once the formula is established, it is easy to figure out the code.
Fibonacci is a natural candidate for recursion, because it need to use data that are computed before in that particular series. Hence, we need to store this temporary data somewhere. In recursion, temporary data is stored on the stack.

Drill Questions
1. Write a iteration fuction that calculates 2^n. 2 to the power of n. n being the input from cin.
2. Write a recursive function that calculates 2^n. n being the input from cin.
3. when n is very large, what are the parameters need to take into considerations?
4. What do you observed for the 1. and 2. when n is very large?
5. Is 2^n a natural candidate for recursion??

[FYP] mini obstacle course

2010-11-21T12:25:00.002+08:00

video src from my student's facebook-> sara

if you wonder how to embed facebook video into blogspot. take a look at the code below. simply replace the video id "167054809983605" with your own video from "facebook.com/video/video.php?v=copy_the_id_here"

[DSA] STL

2010-11-15T08:03:00.001+08:00

My favorite quote from Issac Newton "I am Standing on the shoulders of giants" greatly illustrate the idea of STL. Code have been written by other programmers, using the template feature to greatly help other programmers to overcome programming difficulties. I.e, reduce the time from concept to code.

Being a lazy programmer I am (yes I do admit I like to find the easiest and shortest possible way of writing a piece of code), I do not like to reinvent the wheel.

As in write my own custom code that serves the same purpose as those already written/tested/proven best code by the c++ community.

Why make your life suffer when there are already ready code for you to use?

Programming, in general, is the ability to synthesize code to solve real-world problem by making use of available code. Only in the very dire situation (think high security, high accuracy and the need for real time operation), custom code is needed. *read=> proprietary software*
By learning all the basic building blocks of programming such as template, variable passing etc. When one day this dire state occur, YOU have the ability to create the code library to save the day~!

The STL contains three main components:

Containers
Iterators
Algorithms

Containers, as the name suggested is some form of storage for our data.

Iterators, instead of the programmer manually keeping track on ALL pointers declared and used (not an easy feat when the code is in the range of >10k lines ), this STL-Iterator helps the programmer to achieve the same objective.

Algorithms, fancy writing some code to solve the question in the math tutorial? Here is the partial solution. You need to piece this building blocks together.

Drill question

1. We have written some code to check whether a given word is a palindrome in the previous week, by using some member functions of the string class. Good work guys.
Now, use STL containers, iterators to achieve the same objective.

2. Write a phonebook directory that let the user to store
1. first name
2. phone number

(Store some dummy data into the phone book for testing,)
and the ability to "scroll" the phone book

and the ability to "search" for a particular entry in the phone book.

hint: use ready code from
-Containers
-Iterators
-Algorithms

*non-OOP implementation is acceptable for now.*

http://www.cppreference.com/wiki/stl/algorithm/start
http://www.cplusplus.com/reference/stl/

[FYP] smooth handling

2010-11-11T20:20:00.002+08:00

[DSA] string class

2010-11-09T07:54:00.001+08:00

I hope you have enjoyed and learned some "know how" of writing a program from scratch, with our lil' palindrome example.

To make our lives easier, C++ have lots of library for us to choose from
#include < string > is one of them. Take note string and cstring. both are different!

If you check out the book pg260. There is a piece of code that is very similar of what we have done today. It is using CString instead of String.

Drill Question

Write a name generator (star wars name anybody? hehe) software.
1. The software takes in a name for input and
2. think of the "magic" algorithm to generate a "NINJA" name. Or any name modifiers you can think of. Similar to those name generators you have played on facebook. I guess pretty much of everybody have generated at least once. Code it FREE STYLE ~maybe you want to start by storing 10 sample first name and 10 sample last name. Which gives a 10 to 10 mapping. Easily 100 names~
Append part of your original name to the sample name "randomly".
3. Check out the string member functions attached~

below are the member functions of String. http://www.cplusplus.com/reference/string/string/

Member functions

(constructor) Construct string object (constructor member)
operator= String assignment (public member function)

Iterators:
begin Return iterator to beginning (public member function)
end Return iterator to end (public member function)
rbegin Return reverse iterator to reverse beginning (public member function)
rend Return reverse iterator to reverse end (public member function)

Capacity:
size Return length of string (public member function)
length Return length of string (public member function)
max_size Return maximum size of string (public member function)
resize Resize string (public member function)
capacity Return size of allocated storage (public member function)
reserve Request a change in capacity (public member function)
clear Clear string (public member function)
empty Test if string is empty (public member function)

Element access:
operator[] Get character in string (public member function)
at Get character in string (public member function)

Modifiers:
operator+= Append to string (public member function)
append Append to string (public member function)
push_back Append character to string (public member function)
assign Assign content to string (public member function)
insert Insert into string (public member function)
erase Erase characters from string (public member function)
replace Replace part of string (public member function)
copy Copy sequence of characters from string (public member function)
swap Swap contents with another string (public member function)

String operations:
c_str Get C string equivalent (public member function)
data Get string data (public member function)
get_allocator Get allocator (public member function)
find Find content in string (public member function)
rfind Find last occurrence of content in string (public member function)
find_first_of Find character in string (public member function)
find_last_of Find character in string from the end (public member function)
find_first_not_of Find absence of character in string
find_last_not_of Find absence of character in string from the end (public member function)
substr Generate substring (public member function)
compare Compare strings (public member function)

[DSA] template class

2010-11-08T09:13:00.001+08:00

Template, as the name suggested is a standard or generic way/form we could use for creating different output. For an example, you would ask for a report template from your senior so that you more or less know how what is expected from you.

One of the benefits of programming through a template, it reduces the effort to recode the same function/class but pass in a different variable type. Our good friend the STL Algorithms is the best example of programming template. Imagine the sort() function need to be rewrite again and again and again for each type of variable...............

I strongly do not advocate of getting report from other people and change it to your name. That is not template nor referencing. It is called plagiarism.

A function template or class template, beside used with primary variable, eg int, char, double. It can be used with data structures too. As usual, it is possible to pass in more then 1 parameter of the same or different variable type to the function template or class template.

reference the code below. NOTE: The Code is NOT COMPLETE you need to fix it before you could use it.

Q1. What does both of the function trying to do??? Is there a way to generalize it without repeating the "same" code?
Q2. Populate the given code with a template function that will double each number stored as elements in the data structure. Is it possible to double a char or a string stored in the data structure??

//===CHALLENGE==> HEROES ONLY=====//
Q3. Write a template function reverselist() that could take in a list display the content of the list and store the contents of the list on to a stack and later display the content of the stack.
Q4. Is there a more efficient way to create a test for a palindrome????

[DSA] File Op

2010-11-02T07:54:00.001+08:00

Data need to be saved somewhere. The reason being, if all data are stored in memory and the computer get accidentally turned off. The effect would be epidemic!
Data output using fstream are clear text by default! ENCRYPT any sensitive info before output to file!!!!!

Some text file are delimited in a certain way, for example below.
sample of comma delimited file=> aa,bb,cc
sample of semicol delimited file=>aa;bb;cc

File operations of the program, should be able to read in the lines, and "parse" the input accordingly and stored into the required variable.

This usually happens when legacy software needed an upgrade to the most-IN technology (Programmer Guru Mantra= If it ain't spoil, don't fix it). However, the data are not compatible. One common feature of software, it has the ability to "dump" data out of the system.

As as programmer, we need to write code to extract those that required to the new system. Therefore, we still get to keep our jobs, make ourself valuable.

Regarding on the issue of Out Sourcing to other country. Fret Not. Why would the company would entrust their data to a 3rd party other then their employer? The audit trail of hands dipped into the data would be clearer and easier to trace. Hence the accountability.

With Great monies, comes great responsibilities.

Talking about file IO and security, take a look at the game below.
http://www.takegame.com/logical/htm/boxworld.htm

I played the game when i was still a teenager like most of you. My friend challenged me to complete the game (eg Lvl 99) in the shortest possible time. Few of us, being kiasu (hokkien colloquial for afraid to loose), keep comparing each other's progress. Me, for being me went to my usual corner and gave my friend Lvl99 at the end of the day. Guess how I manage to get it done????

Homework
The sample of file operations are in the writescore.cpp and readscore.cpp. Compile and run it to get a feel of how File I/O is done.

Drill Questions
1. Write a program that READS IN records (eg A.txt) that are semicol delimited eg
tom 19 dcpe/2B/01 DSA B+;kelly 18 dcpe/2B/01 DSA A; .....

2. Write a program that WRITE OUT records (eg B.txt) that are semicol delimited eg
tom 19 dcpe/2B/01 DSA B+; kelly 18 dcpe/2B/01 DSA A; ....

3. write a program that reads in Q1 but modifies to comma delimited and output to a new file.

HINT: It is good to have a menu driven system to choose between the options instead of running 2 cpp projects concurrently.

[DSA] Class & Objects

2010-11-01T08:21:00.002+08:00

In programming, class is a common topic. No matter is C++ or Java, the same concept on class still applies. Killing N birds with 1 stone.

In programming, objects are end product of a class. Objects represent data that are generalized by the class.

Think of the Class as a cookie cutter, Objects are the cookies, the dough is generic material that all cookie need to use. Each object may have some unique attribute(s), such you would sprinkle some chocolate on the dough to make a chocolate chip cookie or add some almond to it almond cookie. In the generalization point of view (the class pov), it is still cookie. All cookie uses the same dough.

Think about it, I went to eat dim sum http://en.wikipedia.org/wiki/Dim_sum last weekend and realize some of the items taste the same. I wonder they use the class method to make it. I.e generic minced meat to make dim sum of different shapes.

How would data be generalized and yet representable?
For an example, Cats and dogs. Both are mammals. Both have four legs. Does it means that the cat is a dog and vice versa???!!! Sure we can think of some other attribute that differentiates a dog and a cat. dog barks and cat meows.

So we can have a class named pets, we can have data attribute of pet type, pet breed etc. Below is the sample code for inventory I have for the dog class for my imaginary dog kennel.

drill question 1, create a class for a cat shelter? Think of the attribute you can put into the class to represent the data of a cat. Some attributes like owner telephone and address should be set as private, and accompany by the neccesary get and set function.

drill question 2, create bank account objects with classes as specified in DS03 Objects Q3.

Notice from the code I posted, I have to manually track the objects, manually remember what objects I have created and use it.
In programming, the ability to link one topic learned previously to another topic, "mesh" the knowledge together is very important. So to speak.
From data structures , we know that it is convenient to manipulate data in a data structure, and depends on the condition we can choose the best data structure to represent the data. Can we "link" class&objects with data structures?

Refer to the code below,

Drill question 3. Based on the class you have created, can you store the objects in a data structure of your choice???? Think of what are the possible applications for data structures "meshing" with class&objects?
HINT: try to use constructors

below is the code for the SpStudent class in the slides, with my comments

[FYP] climbing up a ramp

2010-10-31T14:56:00.000+08:00

well done boys and girls~! We shall not stop here. There are more to come.....

RAWWRRRRRR

[FYP] almost there

2010-10-27T18:29:00.000+08:00

turning the segway using a pot while maintaing balance

[DSA] pointers stuff

2010-10-25T08:00:00.002+08:00

Well done to those that have completed the drill question (well, at least you did the “EASY” one) last week. To those that did my STUN question, KUDOS!!!! By doing this exercise, you have examine the buggy code and correctly identified the syntax errors, logic erros and some went further of discovering the differences of using “cin” and “getline”. The application and synthesis skills, such as isolating the buggy portion of the code, using the debugger, and reading error message from the IDE are particularly important especially in programming. These are the skills that I hope you can exhibit or demonstrate at the future assessments to come.

For those that have yet to attempt, please give it a try. And for those have done, try out the “HERO” question. Everybody loves to be a hero and get "worshiped" (I assumed that is).

Pointer is used for example when sorting a data structure. It is “expensive” to move the data physically, hence, changing the value of the pointer that points to the data is considered “cheaper”.

Below is a chunk of code that demonstrates pointers, the differences when pointers are applied to “char array” and “int array”. YOU are MOST WELCOMED to add more examples of using a pointer in c++.

Pointers come a long history in C and C++, some hate it so much but some really love it. Take it like a durian. Pointers enable the manipulation of the memory directly. PLEASE be EXTRA meticulous when it comes to programming pointers. Commented code really helps a lot for others to look, learn, debug another programmer’s code.

Now Comes the drill question for pointer. Write a program that calculates the volume of a cube (A x A x A), which need to satisfy some "requirement" identified from the "problem analysis" (which is done by me for you)
1. Read in 2 inputs from the user
2. Code a function that takes in this 2 parameter passed by reference and the result is stored in another variable, which is also accessible by the pointer ptrArea. Print out the area for the user.
3. Code another function, which takes in the ptrArea and calculate the volume of the cube.

Now come to the drill question array. Arrays are “containers” that can be used to store data in a structural manner. There are some disadvantages when it comes to using array. First, memory need to be allocated first (static). What happends when there are many copies of the same programme are running? Since memory is allocated, and used up but there are more data to come, array do not have the flexibility to increase like the vector. What are the other cons of using array compare to any other data structure?

Consider using “arrays”. Code a simple 100 seat cinema booking system that will do the following
1. Given (x,y) coordinate set the seat to be occupied.
2. Suggest a scheme/algorithm that detects duplicate seat entry.

[DIY] my LED belt buckle bling

2010-10-20T22:02:00.001+08:00

I was toying with the idea of controlling rows and rows of LED for display purposes. Why not LCD (monochrome)? some may ask. First of all, LCD doesn't display well under outdoor condition and secondly we can see from afar if compared relatively with an LCD.

So there I go finding different ways of multiplexing LEDs. If no multiplexing method is used, I am limited with N number of LEDs. Where N is the number of digital pins available from my MCU. I am not in the state of getting a MCU with 64 IO pins just to control 64LEDs. What a waste of resources.

There I stumbled on the idea of charlie-plexing on the Internet. After reading about it and getting hook on the idea, I am eager to give it a try. But to my horror, the wiring on the vero-board can be quite nightmarish. Any 1 wire connected wrongly can result in a disaster.

I am looking for a better solution, eg a PCB for my own use. I stumbled upon LOLshield V0.1 and it cost USD$99 excl shipping. It is way out of my reach.

I went around asking our staff about it and luckily, I met Mr.Chong SP which he kind enough to supply me a PCB he designed to use charlieplexing for 56LEDs. The experiment time was cut down drastically, because of the time reduce from making the connection. PHEW... programming was not straightforward but still manageable.

But somewhat 56LEDs I am still not satisfy with it..... The number of text I can scroll is limited. Couple of months later, LOLshield v1.5 is going for USD25. I know i got to get my paws on it.
126LEDs in a 9x14 grid! wow!!! Quickly, I made my order and waited patiently for it to reach SG.

I thought inserting of 126LEDs of 3mm is going to be a breeze...but i was wrong......spent about 1hr + just to insert them all....Make sure you get all the polarity of the LED correct. Any 1 mistake will make the whole board defect.JimmyRodges silk screen the LED polarity on the PCB, so you will not mess up with the + and -. How thoughtful.

Next, Apply masking tape of the LED side to support when doing the soldering. The spacing are very small (1.5mm apart) and can be quite intimidating to beginners. I got some steady hands and couple shots of coffee to help me stay focus. I have soldered 126x2 = 252 pins in another 1hr + time.

When soldering PCB of this caliber, make sure you have a really good solder tip. Having a good condition tool is to the success of this toy. My newest soldering iron is getting really troublesome. After a few pins, the heat became uneven and it felt very sluggish..... I changed to my old solder iron which I am reluctant to throw away. Same problem..... The soldering tip is worn out badly. I went digging around my pile of junk and discover that I have a spare soldering tip, but for a smaller watt which I bought earlier but did not get to used it.

On the left is the badly battered soldering tip, on the right is the new one.

Then soldering is really a FASSSTTTTT.... I only spent about 1-3 seconds per pin....I recommend to trim off the excess leads from the LED to as short as possible, roughly 1-2mm above the PCB then solder. I will explain in the next paragraph. My soldering skills are getting rusty, I am getting old and my eye sight is still as good. God knows how many more years I can do such delicate soldering.

Hook up the LOLshield to the Arduino. Note in the previous step. If you do not trim the leads as short as possible, when you fit the LOLshield to the Arduino there might be a gap and caused loose contact. Worst, the exposed leads will come in contact with the USB connector on the arduino. Hence, I covered the metal connector with masking tape to prevent it from shorting my LEDs.

Now, the code part, I am using the basic test from the example. Download to the chip... and....Kept my fingers crossed..........

The moment of seeing all the LEDs light up accordingly, it is really priceless.........all the hours spent did went off.........
Next, I want to scroll some text, but i realised that the library I imported is buggy and doest not support fonts. jimmrodges did release another version of the library. Comparing the modified code is really mentalling taxing. So i used the "diff" function from notepad++ to compare the changes in the 2ver of the lib files.

Life is so much simpler with this small helpers....

Load in the new changes in the lib file... mod the existing sample code to scroll a longer text. Please note that it only supports 22char and capital letters only.

have fun!!! It is going to appear as my belt buckle with customizable text. Anybody wants to shrink the footprint to make it even smaller? LOL

[DSA] stun question Wk1

2010-10-19T08:01:00.002+08:00

I came across this "game" when our department have a staff retreat at the Singapore flyer.

The objective of the game is to arrange staffs into 3 "E" characters.

Since this week our learning topics revolves around functions(), arithmetic evaluations, use of variables and proper programming methodology. I think it would be interesting to write a program to solve it. Anyway, during that period of time, access to a computer is a luxury. All equations have to be done on the paper. I manage to save this data in my memory and it is fresh still.

Attached is the screenshot of the piece of paper that illustrate the requirements.

Assume that the top and bottom horizontal bar is X, mid horizontal bar is (X-1) and the vertical bar is (X+1). Instinctively, this is a classic case where we can solve for X to the total number of staff and use it to form the "E". There is a possibility that there will be some staff remained, because we would want to maintain the uniformity of the 3 "E" characters.

3[(x-1)+2x+(x+1)] = total staff available.

which can further deduce to

12x = total staff available. => that is for forming 3 "E" characters.

Hence forming of 1 "E" character would be

4x = (1/3) staff available

The diagram below are not drawn to scale.

(x+1)

======== (x)

====== (x-1)

======== (x)

But how to translate the problem specs to code????????

we can use a divide and conquer approach to subdivide the problem into smaller portion.

Solving the algebra problem in the program might be redundant, since we have solve it on paper.

Some questions to ponder before start writing the code

a. what are the variables will be used.

b. do we need to use some form of data structure to store the temporary data?

c. what are the algorithms to calculate the X's, to display on the screen.

below are the sub-problem that need to be solve. drill down to further detail is not required.

1. Read in inputs from user for the number of staff available

2. Calculate how many will be left out from the E formation

3. calculate how many staff will form the top, mid and bottom horizontal bar

4. calculate how many staff will form the vertical bar

5. output to a screen

let the code and comments flow in!

[DSA] Common Mistakes in Programming

2010-10-17T16:41:00.008+08:00

There are few categories of mistakes/error/bug in programming. Suchs as logic erros, syntax errors, core dumpz (run time error)/
I came across many many types of mistakes in programming that student commit. These mitakes fall majorly into the syntax error which is the easiest to troubleshoot. As compared to logic errors, there are formal mathematical way to prove that the logic and the premise it holds.

As the old programming guru’s mantra: “It takes more pairs of eyes to spot the bug”

Below is NAF (Need A Fix) buggy code that I have created (50lines only....easy). Your "TASK" is to "SOLVE IT", "FIX IT", PLS DO NOT EAT IT!!!

PLS POST/SHARE your answers here, add in as comments.
//=======================================================

//=========================================================

NO KICK???????????!!!!!!!!!!!

try the below (100lines, 5qns), covers strings, STL containers, iterators. Errors such as syntax error, runtime error and a little bit of logic error.

Note: "HEROES ONLY"

//==========================================================

[DIY] pc based oscilloscope-zelscope

2010-10-14T16:40:00.001+08:00

sometimes we need to use oscilloscope to verify our findings, especially with data acquisition.

But, if you working from home, having the hardware it self is a luxury.

this is pc based. you would need to connect it to the mic input of your laptop/computer.

stereo audio cable, stereo mini 2.5" jack (male and female) both can draw from the store.

if you need to look at a sample. come to my office.

Pls do not, put >5v as input. might damage your sound card.

alternatively, go SLS get those ~~9bux~~ USB soundcard and use that mic input.

Anything fried, will be at the USB sound. Take it as an insurance, ~~9bux~~ 10 bux only.

This is how the usb soundcard oscilloscope looks like

for the software, download here the

http://download.cnet.com/Zelscope/3000-2094_4-10782631.html

there is the free ver, which is not floating from the official website. It is in my laptop

Please note the sampling frequency is only until 44kHz, which is equivalent to the CD quality for the USB sound. Hence, any hi frequency waveform is not able to observe using the software.

[FYP] Almost there....

2010-10-03T23:09:00.000+08:00

Weekends well spent with the students...

Happy Bdae to KKKY too~~!~!

Congratulations Cisco NetRider Singapore 2010

2010-10-02T15:07:00.000+08:00

Congratulations!!!!

You made us PROUD!!!!!
Photo Source: sjteo

[DIY] how to bake a light cheese cake

2010-09-22T14:06:00.002+08:00

Was really tied up with work and processing the semester exam.Finally I found some FREE time to blog about stuffs I have done over the weeks!

The following ingredients called for 2 cakes.

250g Cream Cheese (I used Philadelphia,you can use any type of cream cheese of your choice ).
100g Butter
Leave both above at room temperature.
8eggs , yolk and white separate.
100g sugar (can be reduced to 80g if you are watching the sugar intake)
2 Tbsp (Table spoon) corn flour
2 Tbsp flour
0.5 serving of mango yogurt
150ml of whipping cream (chilled)
1tsp (tea spoon) of vanilla essence

This baking of cheese cake called for the hot water bath treatment (to be elaborated later). I did wrapped some foil on my spring foam pan (the baking tin with detachable base) to prevent water from seeping in.

Sieve the powder ingredient.

Beat butter and cream cheese with the mixer at medium speed or high speed if you are impatient like me!haha

Beat with a mixer untill light and fluffy. How to determine the mixture is fluffy? Where the mixture is beaten until it have risen AKA volume increases, that is about time to stop the mixer. If you are using a manual one, this is a good exercise to burn off the calorie... (which you going to consume later anyway...hahahaha)

Beat in the egg yolk 1 by 1.

Add in vanilla essence
Sieve in (for the 2nd time) the powder in batches and stir with a spatula. Doing for some body i Love, so I did put in extra effort. Otherwise.....
Make sure there are no granules of powder in the mixture. This will affect the texture of the cake

Turn On the mixer, add in yogurt to batter

Then add in whipping cream (chilled) to batter

This is how the batter going to look like after all the ingredients are mixed. We are not done yet. Still have the most important step, making the meringue.

In the mean time, lets go and heat up the oven at 170deg C with a hot water bath. Prepare a pan in the oven, add in hot water until 4/5 or 3/4 filled. Do not fill to the brim, It will overflow and caused scalding. The cake tin is going to take a bath in the pan in a little while. My oven is the those that comes with a fan, the fan is good when roasting. Baking wise, conventional oven is good.

Meringue time.
Make sure your mixer, bowl and utensils are free from dirt, water and grease. Must be very very clean and dry thoroughly.
The egg white must be free from egg yolk too. TURN On the mixer at HIGH SPEED

Add in the sugar in batches

Beat the mixture until semi liquid form. This is the tricky step. In between mixing, turn off the mixer then lift up the mixer and observe the runny egg white. If it is still very liquid form, continue to beat. If it still flow down from the mixer and form a perk, that is the texture we want. If the egg white is beaten until set, i.e. you can practically overturned the container with the white sponge in it over and it will not fall by force of gravity. This is the no no.

This takes a couple of practices to get the perfect meringue. I tried to master it, but it is really a costly experiment. Lab rats are really hard to come by to eat my experiment! hahahaha

Stir in the egg white mixture in batches to the batter.

My mum trained me (never inspired to be a ) to stir in such a way that, it forms an numerical eight. She said this will fold maximum amount of air into the cake.

Pour the batter into the cake tin, and off it goes into the oven into the hot bath.

Bake for 40minutes.

My mum's technique again.....
while(cake!=ready){
Insert a LONG bamboo skewer into the cake,
   If the skewer comes out clean,
   then cake is ready.
   else
   continue with another 10 minutes.
}

I got carried away chatting on MSN with her and forgot to observe the time.........Then i sense a burnt smell......

[DSA] feedback~~!

2010-08-31T11:08:00.000+08:00

RAWWRRRRRRRRRR is Feeding time....ooops feedback time.
feedback about me, you can use the below as a guide

1. my teaching
2. your learning
3. what you have learned from me
4. what you want me to improve on

I hope to see you guys again, prolly FYP or other modules.
It was fun and fulfilling to see you all keep upgrading your code to impress, yours truly.

[FYP] hamster riding self balancing robot

2010-08-23T11:56:00.001+08:00

As promised,
Sudah datang....

NO hamster is harmed in this production!!

actors:
Jack the beanstalk (hamster)
self balancing robot-> KKKY & co

Crew:
SJTEO. camera boy, gives direction but that doesn't makes him a director. ZZZZzzzZZzzz
KKKY and Sara. Robot rigger
Daniel and CWei. Hamster rigger
JLiang: tools rigger
mew: pacifier (for the hamster duhzz)

[FYP] self balancing robot

2010-08-20T14:43:00.005+08:00

This are 2 of the student's FYP i am supervising now.

the common components on the 2 bots
MCU= arduino
accelerometer and gyroscope.

what makes it so different from one and another?
The bot in the 1st video, uses IMU. A chip that have accelerometer and gyroscope bundled into a single PCB. For locomotive, it uses a tamiya twin gear with 2 DC motors on ardumotor.

The bot in the 2nd video, uses a wii nunchuck for the accelerometer and a standalone gyroscope. For locomotive, it uses 2 servo motor.

The main objective is to make a robot that is able to balance on 2 wheels that are position laterally on both sides.
The other objective is to investigate the difference in the algorithm/software/code that need to reflect the different hardware setup.

stay tune,

akan datang.................

[FYP] fire & hazard SOP in lab or workshop

2010-08-17T09:42:00.009+08:00

Today 16 aug 10, yours truly is vising the lab at 5.10pm to check out on the progress of the project.
While moving around the the robot platform ,
explaining the requirements of the robot, fiddling around with the motors and gears mounted to the robot platform.....

Yours truly's micro-fiber business pants came in contact with a hot solder iron that was left on a chair for an extended period of time.

Why is the SOLDER left on the chair!!!??!!!???!!? GRRRZZZZZ

LUCKILY, no roast meat is served for dinner. Poor alan brooke, he did not made his business pants to be heat proof.

An old saying=> You never came lucky, TWICE.

SAFETY PRECAUTIONS

1. DO NOT LEAVE heated elements turn ON

for extended period of time.

2. Make sure all heated elements are inside their guard/holder.

3. Turn off any unattended heating/electrical elements.

4. Work on the workbench.
There is a reason why it is called a "work"bench

[DIY] android on a laptop (live CD)

2010-07-29T18:57:00.001+08:00

my student (WS) from SPIC is exploring on how to put android on a laptop.
After some tinkering he manage to try live CD.
He had put up a very detailed step by step guide. Which you guys can check out from the link below

http://spic.cca.sg/2010/07/27/run-android-on-your-pc-or-laptop/

Since it is booting from a liveCD, no damages will be done on your computer logically.

After you take out the iso image, Your computer resumes as per normal.

 Your browser does not support iframes.

Chromium OS, Cloud Computing

2010-07-02T09:55:00.001+08:00

I had a dream.......

The computers at CSSC does not require a HDD, an optical drive (DVD/CD) nor a installed OS.

The TCO of the computers can be on the cheap.

We could juz load chromium OS on a USB drive, boot from USB and use our computer as if it is a super big web browser.

for docs processing, we could use docs.google.com

for multimedia, we could use youtube with the playlist feature.

for storing of images, i could use flickr , photobucket

for storing of code, i could use snipt

for IM, i could use e-buddy

for social networking, i could use facebook...

hhhmmmsss.... what i could do more on my computer?

but for software development.... it is a little bit tricky......

but.... it is still cool on my development computer.

but for scanning of photos from a scanner... it is a little bit tricky

but for printing of from a conventional printer... it is a little bit tricky

OVERALL.... it is still cool, for using chromium in a CyberCafe type of deployment.

check out the how-to documents of running chromium OS from my young padawan yonglin.

> </iframe>

link: http://spic.cca.sg/2010/06/28/chromium-os/

Chromium is still breaking on computers that sports broadcomm wifi chip. Altheros is still cool.

more info here

http://www.chromium.org/chromium-os/getting-dev-hardware/dev-hardware-list

[DIY] the accidental human conductor

2010-06-08T13:49:00.001+08:00

Usually I would take a break from intense studying by doing some non technical related activity such as cooking, baking etc. But in the office environment, en-suit kitchen is consider a luxury and way out of my reach. Instead, I make little toys (electronics) /handicraft (mastering the art of folding roses) to kill off the gloomy mood from studying non stop.

I wanted to make a Amplitude Modulated Laser Transmitter for Audio. There are many examples (successful ones) plastered all over the Internet.It originates from here ...
http://www.freeinfosociety.com/site.php?postnum=2310

What you will need
1. 1x laser pointer S$1.9 from $2shop.
2. 4.5v battery
3. Audio output transformer (8ohm and 1k ohm impedance)S$1, S$3. This is the tricky one, i shall elaborate later.
4. LDR
5. Speaker, USB powered preferred over passive ones.

Connect them up accordingly. The schematics are available from the link above. From left the laser pointer, the battery pack, the audio output transformer and audio out from the laptop.

Now, hook up the receiver part. The USB powered speaker, LDR.

Now, the tricky part. The "audio output transformer" (branded by the shop with no rating) which was sold to me for $3 does not work. After measuring the impedance using a Digital Multi Meter, it only have 2ohm and 600ohm impedance, a far cry from what I need. The output from laser pointer is very very very weak. The LDR cannot pick up the light intensity. I made another trip down SLT and one of the shop owner sold me a $1 "audio output transformer" . Tough luck I may say, the impedance does not match. The output from the laser pointer still as weak. Hunt around the labs for some spares......no luck at all.

I guess there will be another round of parts hunting, AFTER I finish my exam.

During the 30minutes of playing with the above mentioned toy, i noticed something.

When I am holding the LDR+USB powered speaker's mini stereo jack on my RHS and the laser pointer + messy wires at my LHS. The speaker output some music even though I DID NOT press the "on" button on the laser pointer. Which it should not be the case. When I DID press the "on" button, the music is cut off! For a moment, I thought it is a very strange phenomena that doesn't make sense. But...after 2 seconds... HAHA.....

The first correct answer to that "strange" phenomena and why I press on the button of the laser pointer the music is off, shall get 1x muesli bar from me. Leave your answer on my post as a comment~

Nonetheless, it is still COOL to be the human conductor by touching both the receiver end and the transceiver end to produce some sound without using a physical wire. TRY IT AT YOUR OWN RISK!!! IF you or any parts thereof Got FRIED, I shall bear no liability nor responsibility.

Below is a video of it, still can WOW some crowd if it is packaged in a magic show. E.g, asking an audience come up to the stage to touch an exposed end (eg the receiver side), while holding at the magician's hand. The magician shall strut his/her stuff with the physics behind it.

now... back to the books..........

[news] Top 500 super computers!!!!

2010-06-01T10:55:00.000+08:00

link : http://news.bbc.co.uk/2/hi/technology/10187248.stm

[DIY] light saber ver 2

2010-05-20T20:48:00.002+08:00

Still remember my 15bux light saber i made couple months ago?

I made an upgrade of it, with proper light saber handle...It is kinda cool to take graduation picture with it!!!!But I did not dress up as obi-wan and bring it to the ceremony, it is too eccentric somehow.

I went to the mom&pops hardware shop trying my luck to get parts to make the handle, but some how, lady luck is not smiling at me. None of the parts express their enthusiasm to be modified by me. Then I went to tom&stephanie to buy present for my friends daughter and I bump into a toy that looks like a light saber and it is CHEAP. s$8.90 only.

I did put 3x AAA battery to turn it on and record down the animation. ~~Did not upload it, because wanted to save me from the embarrassment of the toy.~~ BUT, it is still cheap.

Since young, I have a knack of opening up things (+ forgot how to put it back!! haha) and take a look "under the hood". Being young, I have no idea what are the "innard" looking components and the wiring that are so intriguing to look at. My parents are language teachers and can't really help much on the electronics/physics part. It is very important to have a mentor, a guide and somebody to teach the basics and principles of the working. Alternatively, I self taught by experimenting...... but that was a long time ago......

Here is how it looks like after it is dissected.

In the lower container, from left. small DC motor with counter weight to create vibrations when turn on. speaker, small IC circuit for sound & light.

while trying to cut out the excess plastic to make room for my modification, it snapped. So much for a s$8.90 toy. Luckily, it is not affecting the overall stability of the mod.

I got some tracing paper and transparent blue flim (2m x1m) popular book store for s$1.50, but I only use 4" of it. the materials can be save for later use. Line them up nicely, secure with double sided tape and slide in the acrylic tube from the previous light saber. 3R= Reuse, Recycle, Re .... ahem...forgot....

After I finally got the LED strips into the acrylic tube that is lined with the diffuser and colour filer, 3 hours had passed...... I am running short of time to attend the graduation ceremony.....

Went to ah yap's lab to use his power tool to do some fabrication on the handle...

this is the final look of it.

some soldering, mouting and testing... the clock showed 5 pm.... i better get my shirt and tie ready....

boys & girls, May I present to you.... my s$23.90 light saber

this is how it looks under fluorescent light.

[DIY] arduino and temperature sensor LM35

2010-05-15T19:43:00.000+08:00

I accidentally scalded my hand 2weeks ago when I left my solder iron on for a prolonged period and I grabbed the metal guard. It is really a painful mistake. Luckily, no 3rd degree burn of that sort.

So prevent this from happening again, I decided to make a colour changing bling that reacts to temperature. All I is just hook up the temperature sensor to the heat source, for this example, the metal guard. It can be also modified to be fitted into a tap to give visual warning on the temperature of the water.

I laid my paws on RGB LEDs from sim lim tower that cost $1 per piece. It is on the pricey side and i only bought 5 of them. Loaned 1 to nigel and saravanan each for their D&I. Mr.Chew told me last Wednesday he got some for 40cents each (at 100pc lar)!! I felt I was really ripped off....I also have a temperature sensor LM35z lying in some dark corner in my tool box..

To light up R,G and B individually, just connect it to a logic low. My RGB LED is the common anode type. In arduino, this can be achieve by using the digital write.

But, to achieve "blending" of another color, it is necessary to input different intensity of Red, Green and Blue for that "new" colour. Hence an analog write is used.
I have used a 0-255 value, it is the same as programming HTML colour blending.

connect as below
int redLED=11; //Pin11 = Red LED
int blueLED=10; //Pin10 = Blue LED
int greenLED=9; //Pin9 = Green LED
A0 connect to vout of LM35z.

Vout is scaled to 1024 steps for easy conversion.

the code below is for your reference. Uncomment the colour blending part to play with the RGB LED.

take a look at the video. My office is at 20degC -> BLUE, my laptop is emitting heat at 30degC +++ RED. Anything in between, green.

annotating power point slides with laser graffiti

2010-05-03T12:52:00.000+08:00

I came across the GRL (Graffiti Research Lab) website while researching for open platform and openCV to do tracking of an image blob.

I am totally amazed by the ability to draw with a laser, albeit not the emotion they are expressing with graffiti.

So I was thinking, can I used it to annotate my powerpoint slides while teaching?? + the wireless presenter I am issued with to scroll the slides back and forth. It is going to be damn cool lar! commercial product such as "afterglow" is going for usd$1950 per copy for the same feature i mentioned.

quickly, I downloaded the code (I love open source!!) and compile it. The webcam is the input device looking at the whole vision field and the code tracks the red dot (it is called a blob)
you will need

1x code
1x webcam (any model with driver)
1x <5w laser pointer1x projector

check out the video.

sadly, when i run it with power point slides as the background, the slides doesn't show up as the background. More code tweaking ahead and more weekends are needed....

Akan Datang............................

Arduino with servo (360deg)

2010-04-30T15:11:00.002+08:00

arduino with servo motor (360 deg)

There are some servo code that came with arduino.

File->examples->servo->sweep

The servo is from parallax. It is a continuous rotation type. Courtesy of Ah Yap, TSO of T822.

http://www.acroname.com/robotics/parts/R174-CONT-RO-SERVO.html

I don't have a servo controller handy.... http://www.crustcrawler.com/downloads/manuals/ServoController.pdf

So I would just make do with manually programming my arduino to control 2 servo at a later stage.

The the servo takes 6v and 12mA and we do not want to power it directly off the MCU. If the current load is too high,

the MCU might be fried. I really take good care of my arduino, so I will try 1x servo instead of 2x.

Just to illustrate the working of it.

Ignore the sonar in the above picture. It is for decoration purposes.

Hook up servo +6v and gnd to arduino 5v and gnd, data to pin D10.

you can try try the example code "SWEEP" that comes with it and for convenience sake, it is attached below.

Check out the servo in action...

Now the questions come begging, how can we drive 2 servo using arduino (note: data pin only) for a forward and backward movement.

Arduino interface with maxbotic maxsonarEz1

2010-04-30T15:10:00.002+08:00

Arduino interface with maxbotic maxsonarEz1

Maxsonar comes with a couple of flavours to interface, namely the analog and the pulse width. Below are the experiments I have done with them.

Connect MaxSonar pin 5v and Gnd to Arduino's 5V and gnd respectively. I am using Analog pin on max sonar, hence I connect it to A0 on arduino.

The ruler here is to help me to identify whether my readings are as accurate as possible. As I would put my hand across the sonar sensor at 15cm point and hopefully the readings will be 15cm too.

There are some sample code for sonar in arduino itself. I am using this from allen bruce. But he interface it to PING sonar instead.

http://snipt.net/teos0009/arduino-maxsonar-analog-pin/?key=2f06d19e68c5145fe0bbe650d3624ff8

The readings are plain crazy. 35x cm before I move my hand across the sensor. The analog pin is not accurate for short distance. But for longer distance where granularity in terms of 10s' of cm is still acceptable.

Next up, try with the PW pin. PW= pulse width. It is the Tc of the pulse generated by maxsonar that is measured. Wire to pin D8 instead of A0.

Same setup as previous. But the code have to change to reflect the method.

http://snipt.net/teos0009/arduino-maxsonar-pw-pin?key=327e03f8dfda55271e87ed42d99f16ac

The data looks so much more interesting.......

Interfacing Arduino with wiimote (and later the nunchuck)

2010-04-28T08:26:00.000+08:00

Interfacing Arduino with wiimote (and later the nunchuck)

I was toying with the idea of interfacing wiimote to my arduino as my replacement for accelerometer and gyroscope which comes in this package the

IMU Combo Board - 3 Degrees of Freedom - ADXL203/ADXRS614

http://www.sparkfun.com/commerce/product_info.php?products_id=9249

which cost USD$124 which is equivalent to SGD$162.44.

FYI, my wiimote cost me sgd$69 (left over from last year FYP project) and nunchuck sgd$25 (which I got from the shop at clementi city vibe where my student yenyu working part time).

Shall not elaborate about the wiimote and nunchuck...There are plenty of resources in the Internet.

I found out that the pin outs for the wii expansion port (WEP) from the Internet, thanks to the people that are willing to share the data! The drawing are for interfacing the IEEE1394 to the WEP.

Connect pin1 of WEP to Aref on arduino

pin2 of WEP to A5

pin5 to A4

pin6 to ground

I also found out that, it is not necessary to buy a nunchuck, cut out the connector part and used it with the wiimote. That, will render the nunchuck useless (to the Wii ofcourse, later you guys will find out more about my experiment with wiimote and why I have to use the nunchuck instead...........)

The replacement is a IEEE1394 male to male cable for sgd$7 from simlim square.

The pin out on the IEEE1394 and the WEP are carefully map out....

This is how it is going to look like, when they are connected...

Below are the code for sending and receiving data between arduino and pc. Similar code can be found at wiimeadows too! thanks to them for discovering the pattern of data send and receive out of the wiimote.

below are the ASCII art for the data flow of the devices that are hooked up together.

arduino ---wired--->wiimote--bluetooth-->PC

arduino <---wired---wiimote<--bluetooth--PC

Some way, some how, when I open my hyperterminal to observe the data output, I only receive my debug message which is "serial init finished". This means my serial connection of 119200 is setup correctly, but no generated data is observed. No subsequent data is collected both from the arduino through the wiimote to the pc (need to use 3rd party wiimote driver, such as wiimote library on the windows OS), nor the pc through the wiimote to arduino (through hyper terminal).

Used my multimeter to check the VCC and the gnd pin of IEEE1394 pin out, all seems to be correct. Just that no data is observed from the transferring between the devices.

Rewire the IEEE1394 again, with more meticulous effort put in... the result is still the same............................................

Fustrated, because if I can't get the accelerometer readings from the wiimote to arduino, my hypotheses of using it as my sensor would be false!!!!!!

I was contemplating to cut my nunchuck to retrieve the WEP PROPRIETARY connector..........because, I could still use the nunchuck on the wii (As if I got one, hahahah). If In the end, I decided to mutilate the nunchuck. Plug in the connector to the wiimote and the exposed end to the arduino.... No eureka moment.......... the data output is the same as the IEEE1394 cable........Very fustrated................................because of my hypotheses would failed..........................

But, which part went wrong?????? I am still finding the cause of it..........There are success stories on the Internet that used the similar setup.......

Before the last straw to be thrown, I tried to hooked up the nunchuck to the arduino instead.

with the code attached below

Atlas.... some readings from the accelerometer on the hyperterminal...data from the nunchuck.......

[DIY]{arduino} POV

2010-04-19T14:41:00.002+08:00

my POV (persistence of vision)

some years ago, i created a spinning LED display on my decommissioned hdd. I want to display message and time in the air, while the HDD spins. Basically I opened up the HDD, attached 7LEDs to it. Hook it up to a PIC16 which is the only MCU that is made available to me at that time. The result turns out to be very bulky, and I need to use a computer PSU (power supply unit) to on the HDD and a separate step down circuit for supply 5V to my pic16. During that time, I am still using a non-cam HP nor I have a camera and I do not document it down. BUT, the know how is already with me.

Ever since I got my hands on my arduino and my protoshield ready I have been toying with the idea of making 1 POV that is easy, less bulky and can fits into my palm in a snag. So that when I sing/dj in a concert, my fans would gyrate with their hands in the air and write a message for me with the POV (I hope is not asking me to stop singing!!). The EGO meter will shoot rocket high, so does my blood pressure. haha

you would need 1x arduino+protoshield, 8x LEDs, 8x 330ohm resistor and code.

I am using the digital output of arduino, current limited by the resistor to the LEDs. This is how it will look like after hooking up all the components.

The Idea behind POV is to play a trick on the human eye. It is a known fact that human eye see things at a rate of 27Hz.

That is our eye's refresh rate. So anything that refreshes above that rate, the eye cannot notice the flicker.

Say I want to display the character "E" in a 8x8 matrix, the col is indicated with col1, 2 and so forth, row indicated by LED #.

col1, 2,3,4,5,6,7,8

Led1 ********

Led2 *

Led3 *

Led4 *****

Led5 *

Led6 *

Led7 *

Led8 ********

I would light up the matrix column by column and each of the column is differ by 2.5ms (400Hz), this is only to light up 1 character.

If I want to light up a message say "EEE", I need to repeat the process above for each of the character.

Straight away, I know that I need some form of loop control structure to display column by column, and character by character.

Furthermore, I need a data structure of some sort to hold the message. The easiest way is to store the characters in a 2D array.

To make my life easier, I am using this website to help me generate the 2D array for the message to print.

http://www.repulsor.net/minipov/

I have a code template for you to use. Fill in the loop control structure and the message to print in the template.

After finish programming, I need to test that all LEDs are working at the init of the code. It is cumbersome to swing the breadboard together with the USB cable. Hence I made a 9V battery connected for it.

Below is an example of POV.... note that I hold my camera upside down....

What message am I printing????

What can place you can think of to use with this "toy" ??

[DIY] how to start programming with arduino

2010-04-19T14:09:00.003+08:00

Download from the arduino website.
Extract the downloaded file into a folder
proceed to \drivers\FTDI USB Drivers and make sure the drivers are in it.

Plug in arduino to the computer using the provided USB cable.
When it prompts to install driver for the USB to serial converter, point it to the location where 3. is located.
After installing complete, a reboot is necessary.
Click on to start programming.

This is how the IDE looks like.
each project is called a “sketch”.
In this location, there are sample codes on how the arduino can be used. We will use file->examples->digital->button.
Make the connections for the LED and the switch. Connect JC1 to pin 2 and LED (JC2) to pin 13.
Click on play button to start compiling. Once compiled, below screen will be shown.
Click on to upload it to arduino.
Press reset button on arduino after download to start the code uploaded.
Happy programming.

[DIY] {Arduino} Protoshield

2010-04-19T10:48:00.002+08:00

Arduino protoshield

I was toying with the idea of buying an arduino http://www.arduino.cc/ for some time. It is one of the best open source MCU, complete with sample code and comes with 6 analog in and 6PWM (depends on the flavour). The best thing I liked about arduino is, it comes with many many "shield". Each shield serves a specific purpose, such as the motor shield, the ether shield etc. The shield package comes in a kit set. Hence, the low cost.

The price is not prohibitively expensive, but some how I spent my disposable income on my other research interest....Recently I got some cash to spare (not a windwall tho) and quickly approach my colleague Mike Ong to help me to contact his supplier get a set of protoshield and arduino. His supplier quoted me

Arduino Duemilanove = $52.80

Arduino ProtoShield V.4 Kit = $15.70

mini breadboard = out of stock

Good pricing! For $68.30, I can play it for a very long period of time.

So..... what is this protoshield alll about ?? Basically it is a mini development board for the arduino. Instead of using the big breadboard the store issued me and having many wires extending from the arduino to it. Sadly, the mini breadboard I wanted was out of stock....

The protoshield comes in a kit form. The PCB is of a very good quality, each description on the pin can be seen clearly.

Close up of the PCB

There is no instruction manual that comes together with the kit. Nevertheless, it is very straight forward to mount the components by reading the description on the PCB and do the soldering. The LEDs have their cathode filled off and it matches the pattern on the PCB.

Now, the soldering part. Secure the components with some sticky tape/masking tape or what ever tape that is convenient to you. Flip it over and let the soldering begin!

This how it looks like, arduino mounted with protoshield. Let alone the name sounds so coOOOooOOooOOoOL right!

I insulated the USB mini connector with some masking tape, because it is dangerously near to some of the points I soldered.

For the next 2 hours, I am playing with PoV (persistence of vision). Some of the staff, my project's boys and girls have seen it

I know I owe all of you the how-to. Writing a how-to actually takes more time then playing with it... *sigh*

I will try to write the how to for using the arduino IDE, that uses PROCESSING (another C-like programming language) and the how to of my PoV.

AFTER I attended my meetingS............

[DIY] kinetic hand phone charger

2010-04-14T19:20:00.002+08:00

my attempt at Kinetic handphone charger.

I received this toy as my christmas present (after some present exchange game that too difficult for me to comprehend) last year. It is a handphone charger that is powered by a 1.5v AA battery. I tried it on my HTC magic... and it works. 1AA battery can charge about 5% on my phone.

I was tinkering with the idea of marrying the circuit in the AA battery charger with a kinetic to electric generator (aka the shaker) which works on the concept of rare earth magnet's magnetic flux is cut when it is moved in and out of a coil of enameled wires. http://en.wikipedia.org/wiki/Faraday's_law_of_induction.

The basic construction of the shaker is a rare earth magnet, sliding in and out of a acrylic tube that is coiled by some enameled wires.

I also need a circuit that made up of 4 diodes (1N5819) and a capacitor (10000uF) to make the output into a constant DC. A voltage regulator LM29317 can be added too. Ai Ling the TSO is kind enough to provide me the components. thx!!. This circuit gave me about 3v across the load.

Since the AA charger only needs 1.5v, if I can supply constant 1.5v to the AA charger through my shaker, I would be able to charge my handphone for FREE!!! (assume cost of energy acquired from food is FREE)

I got my rare earth magnet from a shop in sim lim tower basement 1 for $18. Use the remaining acrylic tube from my light saber project and now I need to coil 1400 revolutions of enameled wire on the acrylic tube. Ask around the lab TSOs for it and Hamzah show me some which is left over from a previous project. Now the challenging part is how am I going to coil 1400 times by hand!?

My first attempt trying to coil by hand... very tiring. Wanted to use a power drill, but none of the bits fit my acrylic tube......and I lost count after the 300th revolution.....

My 2nd attempt, with the power drill. The bit is a knob I salvaged from a variable resistor........

Apparently, there is this antique coiling device that is sitting somewhere in the cupboard. I only discovered it after I have done coiling with the power drill....

I have varied the simple circuit of the above to provide better charge storing (2x capacitors) and capacitor to stabilize the input of the LDO .

After couple of shakes............ not to bad, the voltage is 4.43v and current in the range of 0.9~1mA.

More then enough to power an LED, but how about charging my phone through USB????!!!

USB on my laptop provides 5v and 100mA per port to charge my phone. The current might be an issue here

After hooking up the output of this circuit to the input to the circuit of the AA battery charger then connect to my phone through the USB and after many many many many many many many many violent shakes, my phone is still not charging....

Voltage across the load is still 0v after many violent shakes. the capacitors are not building up charges as fast as the discharge....

My hypotheses might be WRONG!!!

with a sore arm, a dented ego and a finite FREE time to play with my hobby,

akan datang ...................

[DIY] light saber with SOUND!!

2010-04-07T14:22:00.001+08:00

still remember my DIY light saber which I made couple of weeks back?? http://shin-ajaran.blogspot.com/2010/03/diy-light-saber-with-15-and-60minutes.html

I brought it to BarCampSingapore5in SP, gave a flash talk on how to make it. the response was OK, there are some jedi out there in the crowd... One comment from the ground was.... where is the sound from the light saber. It suppose to have the VOOOOM sound every time the light saber is swing.

OK, Sim Lim Tower Here I come again!.........
there are 2 parts to solve this issue.
1. the mechanical motion detection switch
2. the voice/sound electronics.

item 1 was tricky to solve, because the COTS available is out of my reach. I tried to fabricate one with ball bearings and some metal plate, a close circuit will form when the metal ball bearing touch the metal plate. The outcome is not satisfying. I am using a roller switch instead.

item 2, i bought a "puma" voice digital kit for $8 at SLT, so that I can quickly hook it up to my light saber.

Sadly, on the first try, nothing worked!!!!
The troubleshooting begins~!~!
The transistor is configured as a BJT and act as an amplifier in the circuit, and the IC is the one that generates the sound. The kit's PCB (printed circuit board) and the IC chip does not contact properly, there is some miss alignment. Small issue I presume and I ignore it.

the voltage between base and emitter suppose to be 0.7v when it is in forward biasing, eg the transistor is working. But, i got a 0v reading on my multimeter. The best part, voltage between collector and emitter is 2.7v which is the voltage of my supply. it means that emitter and collector is shorted, e.g spoilt transistor.
All the other components tested fine, except for the chip alignment... small issue....I think....

Can't really sit down to trouble shoot, because in between office hours, I have to attend meeting and conference and the circuit is left at a corner paralyzed.......

When I got the time to fix it, Thinking that is the transistor fault, I swapped it with another spare I have. But I do not have the exact c9013 low power and have to used another NPN equivalent make the chip contact to the PCB closer with the use of the piece of paper as spacer. When I decide to cut the PCB to make sure the alignment is accurate and solder the chip's contact and the PCB contact
this is what i got... random noise.....

Is it the chip is spoilt, or the transistor i swapped is not working. The only good news, voltage between emitter and collector is not 2.7v and voltage between base and collector is 0.5v.

I deduce that, it should be the transistor, so I changed back to the default one and voila~!
I got my "PUMA" roar. but.......it doesn't sound like a puma, more like a creepy animal you watch on horror movie...

The whole idea of using a swappable chip is such that when i get my paws on the VOOOM sound chip, I can easily hook up to my circuit. Since now I solder down already to make the circuit more realiable, this is not any option. Nonetheless, I "wire wrap" it to my light saber.

this is my small button battery that gives 3v all together in the light saber. I did not share the 9v of the light saber coz i would need to use another voltage step down circuit (lazy lar duhz..... my excuse of not enough time..hahaha)

Me playing with the light saber in the office...

[DIY] light saber with $15 and 60minutes!!

2010-03-26T09:36:00.000+08:00

Last Saturday, After the whole day in office reading, trying and experimenting for my academic usage.... Out of sudden..... I question my self. What am I doing in the office on a Saturday??!!! Whereas my friends are busy preparing to party. Well, in the long run I see in my self there are some significant benefits for seeking knowledge and most importantly applying it. Instead of joining my friends to party and getting wasted the next few days (wasting time sleeping duhzzzz), I decided to make my self a LIGHT SABER, just to perk things up.

Sim Lim Tower (SLT), here I come again!

Window shopping around and I chance upon this flexi LEDs in plastic strips that run on 12V DC. Aha! The perfect illumination for my light saber. Best part of it, it is only sgd $15 and the shop next door is selling for $45!!!!!! absolutely the same real deal. Delighted with my find, I headed back and continue with my books.

Some of you might wonder, what colour will my light saber be? I choose white instead of the available red, green and yellow LEDs. Just for pragmatic reasons, I can still use my light saber as source of illumination. Don't you think is eerie to read in green lights?

The next few days are spent on hunting parts for the light saber. I went to T822 look for ah yap for some acrylic tube, diffused the clear acrylic with tracing paper in it and there it go my spoils from last Saturday.

This is how it looks like incomplete....

I am toying with the idea of making a really uber cool steampunk looking light saber handle. Found some really cool ones from the Internet, but........... I can't afford the time to hunt for the parts, assemble and fabricate them and not forgetting blogging about it.. hahahaah

Just made do what I could find in my office. Emptied plastic holder for solder coils, some paper clips, 9v battery clip some wires, a variable resistor for showing strong and weak force and NO soldering involve (save time!! but might break down anytime from rough handling)

The FORCE is STRONG in this one

Your Focus determines your DESTINY

May the FORCE be with you

[DSA] Feedback

2010-02-19T13:34:00.000+08:00

Feedback about me regarding

1.my teaching
2. your learning
3. what you have learned from me
4. what you want me to improve on

I hope to see you guys again, but not in the same module!!!!!
It was fun and fulfilling to teach your class.

[DIY] LED fiber optic bangle BLING

2010-01-14T18:21:00.000+08:00

I had some spare 3mm fiber optic cable from my student's FYP project, since they only use some of it to direct IR light source to a very focus beam to use on their IR camera.

It would be a waste to leave the balance items at one corner, collect dust and hopefully some day later some people would discover it.

Remember my Blinking LEDs belt BLING???? http://shin-ajaran.blogspot.com/2009/10/diy-blinking-led-bling-belt-buckle.html

I found one of blinking LED on my pile of parts, very lonely and in need of some serious company.

Quickly, I use some heat shrink tube, a 5mm blinking LED, 2x 1.5v button size battery and 10cm of the fibre optic cable to make a bangle. Very cool when used in dark environment.

If you wonder how it works.... check out the video below..... BTW, I took this video in my office with lights switch off and most importantly, in a very dark corner (below my desk). With fluorescent light (read: good for reading book), the light from the LED is barely noticeable.

1x bling LED: $0.5
2x 1.5v battery: $2
10cm fiber optic cable:$1.2 ($12 per meter from SLT B1 Continental electronics)
time:10minutes (OK, I din factor in my wage. Because now is wayyy pass 5pm.)
total cost:$3.7

merry christmas + happy new year

2009-12-25T14:39:00.004+08:00

As usual, half day on christmas eve. The air-cond was turn off at 1pm and I am still in the office trying to get my things done. With my small little fan, it start to get cooler but not until the sun shine again. It became too warm for me stay in the office.

As usual, public holiday eve, there are people EVERYWHERE! I wanted to avoid the crowd, the aimless drinking and partying on the excuse that it is a public holiday eve. Wandered to Sim Lim Tower (SLT), I am sure the crowd there suits my palate. Walking in shop by shop to hunt for a temperature sensor for my new toy (some of you might heard it straight from the horse's mouth and want to be part of the action) but none avail. I was tempted to ripped off the temperature sensor on my motherboard. haha

Chance upon some kit set at B1 in SLT. wireless VU meter!!!!!!!! What is better to do then having a wireless VU meter to decorate my office!

Can't wait to open the kit set. So I hurry back to my office where all my tools are available. Spent the next 2 hours playing with another simpler VU that is passive. It is already 10pm....it is about time to head home.

=================================================================

Wakeup, exited about my wireless VU, here I am again in my Office. But to my dismay, the security guards locked the doors of the corridor that leads to my office, on christmas day! Hungry, eager to make my toy, frustrated because I have to wait and certainly not in a very good mood. Call them to unlock the corridor door.

I made the input ports and output ports detachable. Once I got the circuit running I want to hook it up to my headphone, my tshirt etc. Kinda cool when I am DJ-ing in the pitch dark with funky LEDs that lights up according to the sound pickup from the dance floor. Any SP-DJ kids want to loan my set? hehe

Here I present to you my toy for this christmas.

It reall rox!!!!!!!!!!!! check out the video

the dillemma of not preparing to tackle a challenge

2009-12-07T09:22:00.002+08:00

Some time in July 09, sitting on the table for a casual dinner....

After a few drinks and merry making, I was dutch uncled by the boys and girls at the dinner table. 4 of the guys are regular marathon runners. 2 of the ladies run 10km regularly. I am the only "dude" that eat+drink as much (or more) then them but minus the physical exercise. Call it peer pressure, which I succumb to it willingly. Because i know that i need to exercise, if I want to see the moon again when I am 60 years old.

The next couple of day, I received an email telling me that i am participating in SCSM09 - HM. What? I never paid for it....Anyway, found out that my friends help me to register and I got to pay them back. 21Km, seems to be very loooooooooong ....... When I go to gym once in a very blue moon, I can't even complete a 2Km slow jog. Logically, 21Km requires 10x of the determination and effort.

Since then, my friends took turn to run with me. Usually we would run the perimeter of the campus. Because I ran so slowly and lack of motivation, they have to push me from behind both physically and verbally. Came to a point that it is abusing already. But I just smile at them and continue with my antics. Eventually, nobody would run with me anymore.....

Sounds familiar?????? It is like the studying for a subject. Especially subject that you do not like it very much or hated it completely nonetheless.

Fast forward to Dec09. With very little training (I only ran 10Km once in Aug, not even 4KM per weekly basis), I am having second thoughts of going for the run. I read the maps in detail, trying to look for an "escape route" along the path. I even have the thoughts of completing it "virtually", by tagging the chip on a stranger (by putting in their pocket or something like that). This lack of confidence is the true reflection of not preparing for the challenge. It is like exams is coming in few weeks time but did not study nor prepare for it. Sitting for the exam is simply for the sake of taking it and hope that will pass the exam by luck.

Usually I would over prepare before I take any exams. I actually look forward to take the exam and not the other way round. Somehow, this mental capability does not reflect on my physical capability. Or is it because of my lack of empathy to work out physically?

My friends run the 42Km marathon, they start as early as 5am. Leaving me alone waiting for my flag off. Thoughts of escaping keep seeping into me. The thoughts of running away is so strong. I start to make excuse such as I would hurt my self during the run, take photo as "COP" (Certificate of Participation),run for 2km and go home after that. Sounds familiar again??

This is the Fight or Flight Situation...

Until I met Mr.Seow warming up, have a chit chat with him and he gave me some positive reinforcement. We started together and jog the first KM together. He left, because I could not catch up with his pace.

At the 2nd KM mark, I can still jog albeit slowly. I kept jogging until the 5Km mark, where I met this uncle. He is 2x my age, had a mild stroke before and sharing his life changing experience with me and the reason that kept him moving. This resonates with the fear within me...We jog-walk-jog intermittently together. After the 7Km mark, I bump into Mr.Seow again.

Uncle was stopping at the first aid station to get some help for his knee pain. I am all alone again. Along the way, a few people gave me a pat of the back and keep encouraging me. At the 15Km mark, Andy bump into me. Tell me to try harder.

At the 17Km mark, blisters develop on both of my sole. It is really painful even to walk. Thanks so much to the $200+ running shoes. I kept jog-walk-jog, not wanting to lose the momentum. I knew once I sat down, I would call a cab to go home. I saw people that are bigger size, heavier and less healthy then me also keep moving forward.

Savor the last moment to the finishing line. Strangers enthusiastically cheering for strangers. Not forgetting the muscle ache after the run too!

New Year Resolution

2009-12-01T09:46:00.000+08:00

It is around the corner again during this period of time, where you made some self reflections on the one year that have passed. Any of you still remembered what did I set at dec08?
http://shin-ajaran.blogspot.com/2008/12/new-year-resolution.html

Wasted 2009? Thinking of something you want to do but procrastinated/idled/let time pass by???? --> so passe, it was mentioned last year. haha

I, inevitable, procrastinated my way to the 100KG i am now. --> I am now 95KG, just measure it yesterday night.

<<[2009 Goals]>>
1. Drop 1 Kg per Month Tried but failed to do it. Otherwise I will be at 88KG now.

2. Participate in Sun Down Marathon 30th May 09 been busy "lah" (sounds so familiar right?) Anyway, i participating Standard Charted Marathon on 6Dec09

What are the caused of the failure of not achieving the goals?
Let's analyse the way my goals are set. Still remember my "SMART" goal setting technique?

When it comes to setting goals, be very sure the goals set are "SMART"

S= Specific / Simplified / Strategic
M= Measurable / Manageable / Money ?!
A= Achievable / Attainable / Agarlogic?!
R= Realistic / Relevant
T= Timely / Track-able / Traceable

What is missing from the above, is the how to's to achieve your goal. More importantly, a schedule on what to do that you can follow closely to achieve your goal. Since i did not paste on my wall my workout schedule as big as loan shark ah long's, hence, nothing is tracked closely and finally nothing happened.

More importantly, I have made a promise to her that I would cut down 2KG per month. She did 5KG per month. Oh my goodness.....
As I told my boys and girls, you are only worth what you have promised. It is either you keep your promise, or not. Will I end up self-pwned? Lets see on dec 2010. I am actually looking forward to it. hhahaha

[warez] fun with plasma ball

2009-11-23T09:23:00.000+08:00

Still remember my USB plasma ball toy? http://shin-ajaran.blogspot.com/2009/11/warez-usb-plasma-ball.html

I have decided to play around with it using a fluorescent light tube. But what worries me was the power rating of the usb plasma ball. It is running on 5V, 110mA from the USB. I am not sure whether it will work on a 2' 10W fluorescent light tube. Anyway, i got a 8W 6" fluorescent light tube for the repair man I bump into this repair man when i was conducting my lab session. He is kind enough to loan me for a while. thx man~

[warez] poor man's projector

2009-11-18T18:16:00.002+08:00

Google Docs ROX!!

I was toying with the idea of owning a projector at my pad. So that I can watch movie, play games, do word processing, write code on the BIG screen. It's year end nearing the corner and this is the time where all the "crazy" sales begin. But The projector's price still as "crazy". Ranging from s$1k and above for a XVGA ones with acceptable lifetime of the bulb. I should save my year end bonus for paying the education loan i have taken and pay for more important stuffs (buying a LV neverfull is never important! duh...), instead of splurging on warez.

I am not going through the details about LCD technology, but here is where you can read more about it. http://en.wikipedia.org/wiki/Liquid_crystal_display. I love wikipedia!

By reading up on how LCD monitors are constructed. I could have remove item2 on the picture and replaced the back light with a light source from the OHP and "tahdah" my projector! There go my frenzy search for spoilt LCD and OHP. DO NOT THROW away your old warez, breath new life into them. Alternatively, you can donate it to me! hahaha. I would like to thank monir, pauline and chin hee for sourcing the written off items or faulty items such as the LCD, OHP and tools. Items are really old and chuck in a dark corner, until i salvage them. Proceed with care. Observe safety requirements and bleed the voltage stored in the LCD monitor before proceed by disconnecting from the mains and let it sit for some time, I do not have a professional bleeding circuit on hand nor i am making one. Too hazardous....

What I have used.

1. 1x Phillips Brilliant 105p 15" LCD monitor (FREE)

2. 1x OHP (FREE)

3. 2 wednesday afternoon (PRICELESS).

This is the LCD monir gets me. After removing the base stand from the LCD (requires some yanking and potential risk to crack the plastic housing), Unscrew the nut that holds the back panel to the LCD. Look out for the latch that hooks the lcd monitor housing in place. Usually, they come in a pair.

carefully lift the front panel cover after unlatching all the sides.

Remove the plastic front panel carefully, without damaging the hooks and latches.The black glass material in the picture above is the LCD. Handle with care.

This is the connector for the IO panel which the power button resides. Remove with care. It will be used again in the later part.

The push button and LED to the right is the power button and power led.

Carefully lift the black glass material that is hold in the metal frame. Here i used 2 screw driver as the lever to lift it up.

This is the reverse view of the panel lifted out. Inside the metal housing which sports the vga out, dvi out and the power socket is the controller board for the LCD. Basically power driver circuit for the back light and graphic display driver circuit for the LCD. The yellow ribbon cable is the ones we disconnected in the previous step.

Unscrew the screw that holds the metal housing together. In this picture it circuits mentioned above. On the right is our power driver circuit to the back light. on the left is the graphics driver circuit. Note the orange coloured ribbon cable. Remove with care, because we are using it. I use my smallest flat head screw driver to slowly pry it off.

clearer picture. I removed the metal plate below, thinking of putting it in my plastic hobby kit box (for insulation). But the cables are simply too short to handle. To save time and hassle, i just use back the plate. More about insulation later.

This is how the ribbon cable looks like after it is disconnected. Gently peel of the metallic sheet, the black foam separator. They are self adhesive on the LCD.

To remove the metal frame at the perimeter of the LCD from the panel is a little bit tricky. Because the metal pieces are bent towards the grove. So, just bent it the other direction as in the picture above.

This is how it looks like after the metallic sheet is lifted out. The white colored plastic frame have to be removed from the LCD. The PCB is green in colour. Do not scratch, break or remove any connections from the PCB. These are the data lines to light up each pixel of the LCD.

The screw in the above picture is the main hindrance for me to complete this project within the same wednesday afternoon. It is so small, such that all my screw driver bits will not fit. Luckily, pauline ,manage to source one from me. To the right is the connector to the LCD panel from the graphics driver circuit. To the left are the data lines connector. DO NOT REMOVE the plastic cover, those are the ribbon cable.

DO NOT remove the plastic cover that holds the ribbon cable. Unlatch the black latch to the white groove.

Behold, the LCD panel at all it's glory and the back light at the background.

we are using the lcd panel in black.

The OHP that chin hee get hold for me. It was dusty and littered with lizard poo. Got to clean it before use.

The next step is to snap the ribbon cable from LCD panel to the graphics driver circuit. Secure it somewhere to the OHP. I used 1 cable tie to secure it and laced some plastic sheet to provide some insulation. Assembly was a breeze. Please do not do it without supervision or safety precautions.

Now, the viola moment. Or i have another paper weight on my desk?

Look ma, there is picture in the well~

The projection is not as fantastic. It have a yellow tinge on display. I guess the OHP is really aged. Time to change to a xenon lamp!

The end

[warez] USB plasma ball

2009-11-09T13:21:00.002+08:00

After 3 weeks of agonizing wait, my usb plasma ball finally arrived~ yeaaayyyyyy!! 1 more coooool display in my office. I am another step closer to make my office into more disco-ish.

The best part of it, powered by USB, 5V and 110mA. Yet to try to power it with some dry cells. None to be found in my drawers. Arghhzzz

was discussing with yushan this morning, whether i can use his robo complete with the wheel to make a generator to power it. stay tuned

If you wonder what is plasma is all about, please read..

http://en.wikipedia.org/wiki/Plasma_(physics)

[DSA] posting of link in comment box

2009-10-28T08:30:00.001+08:00

pls use HTML code

The following link is done with
www.google.com

<a href="http://URL" > the link < /a >

still figuring out how to post js in the comment box. as for entry, no problem encountered. If you have a solution to it, I did like to hear from you

[DIY] Blinking LED bling belt buckle

2009-10-08T11:17:00.004+08:00

Last Last week, attended one of my secondary school classmate's wedding. Btw, late Sept and early Oct I have already received 4x invites to wedding. More are in the pipeline..oh my goodnessssssss...........

Arghz, wedding reception is soOOooOoo boring. The food is usually not on par (mass produced), the alcohol is crazy (I'm in the brotherhood team, I'm used to blockade drinks targeting the groom.No drink driving please), lots of photo taking (I don't like to be the subject and I insisted to be photoshopped!!!! RAWRRR)

What totally grab my attention was my the first dish served, the cold platter. The lights are dimmed, Techno song was played (yeay!!!) and at the center of the dish there is this very "beng" blinking LED. It is in the shape of a dome, served in a cup of lightly coloured agar-agar (to give the light a medium to be illuminated). Quickly my I laid my paws on it before my bro daniel get to lay his! haha

Can' wait, I fished out my phone switch on the flash and tried to open the dome. But it is secured by screws! Well, I usually carry a handy tool set with me. No effort at trying to pry it open.

What drove me thinking was, how possible to pack 1 LED, some sort of controller/pic/MCU and battery cell small enough to fit into a dome shaped container at the size of a 20cents????

The content of the dome is just 1 LED and 2 button shaped battery (gives 3v). But, where is the controller???? Upon close inspection of the LED, i saw a tiny weeny black chip in the LED itself. That briefly explains the whole LED blinking sequences. My girl said I am "sua gu" (frog living in a well)...

well....I am pretty much exited with the "new" toy, open it up and find out that I can easily make 1 myself too without the hassle of wiring up a controller/MCU/pic and the considerations to make it small enough to be portable. The sample dome is in my office.

"Inspired" by this blinking LED, I was telling my trainees about this bling i going to make.

It is basically a belt buckle, complete with flashing LED.

Went Sim Lim Square (SLS) and Sim Lim Tower (SLT) last week for window shopping.

What?? Window shopping at SLS and SLT??? Not orchard ION, illuma? you gotta be kidding me!

Was hopping in and out of the shops in SLT looking for cool kit set and wares i can play with.

Chance upon this Flashing LED that cost 50cents each. They came complete default with flashing sequence, such that, there is no need to have a pic/MCU attached to the LEDs. Small is beautiful.

Initially, I only want to use 3v (button sized) to light up the LEDs, so all LEDs are wired in parallel circuit. Because there are too many branches and the current are divided at each branch of the circuit, it is not enough to drive the blinking LEDs. Normal LED are still OK. It Is in the circuit as a referencing point for the "beng-ness", lumens [brightness]. Actually, i only bought 10 of these. "LED not enough lar".

here I gave you my prototype belt buckle, 3v and 9v powered. Can spot the characters I am flashing?