Project "DIY FreeTrack IR Headtracking for PC"

i stumbled upon the concept of headtracking for the PC some two years ago when i was very into flight simulators (still am, but there aren't any new simulators that capture my attention). again, like the DIY PS3 mouse and keyboard adapter, i did not create or program this...i just followed the instructions online. 

basically, by using a webcam for the computer and some infrared LEDs, you are able to build your very own headtracking device that would work in games that support it (most flight simulators, racing games, even some first person shooters). so instead of using your hatswitch on your joystick or the buttons on your keyboard to look around in your virtual aircraft's cockpit, you can simple move your head around and your viewpoint would change accordingly.

i actually smashed this setup together nearly two years ago to see if it works (and it did) and then i forgot about it after awhile. i didn't do a good job at all putting it together, but the idea now is to show how it works so just ignore the loose wires and *cough* universal black tape. there are two main versions of the 'rig' which is either mounting the LEDs on the rim of a cap, or mounting them on a 'clip'. many users have posted their builds here: http://www.free-track.net/english/hardware/point_model_gallery.php

the official name for this sort of device is a 'optical motion tracking' game controller. if you know how a Wii remote works then you already have the basic idea because it is very (if not entirely) similar. the official commercial product has been around since 2001 and was known as TrackIR 1, with the most recent version (TrackIR 5) being released in 2009. TrackIR retails for $150USD(!!!), and budgety ol' me doesn't have that kind of cash to blow on what is essentially some LEDs, a webcam and professional software. after looking around on the internet, i found a free(!!!) program created by some geniuses over at http://www.free-track.net/ and the best part of it is you have to DIY a simple rig together to make it work. 

by putting 3 infrared LEDs together in a triangle (or line, depending on whether you're building the cap version or the clip version) of specific dimensions (depth and height), the webcam and software would be able to detect and calculate how much and in which direction you move your head (as mentioned, like a wiimote). using 3 LEDs would enable six degrees of tracking; pitch, yaw, up, down, forwards and backwards. there is a version that uses only 1 LED but then you'll be restricted to just pitch and yaw as there is not enough information to calculate the rest.

looking through the parts list, it is obvious it won't cost you more than a few bucks (cents for me because i already had all of it lying around):

- 1 x resistor

- 1 x standard USB cable

- 1 x cap

- soldering kit + wires

cut away one end of the USB cable and solder the resistors to the positive (red) wire to drop the voltage down to a level the LEDs can operate at. solder the LEDs together in series with enough wire length to space them apart to make the triangle of the specified/desired dimension. ignore the really shoddy build as shown in the picture below, it was hastily put together with nothing but black tape holding everything in place and the cap was the only free cap i had lying around (coincidentally its from the airshow and i use it for my flight sims...)

there are quite a few webcams that are well suited for this program and there is a list here : http://www.free-track.net/english/freetrack/comment-ca-marche.php, i borrowed a microsoft vx-1000 from my brother and it works fine.

if you're wondering why infrared LEDs are used, it is because they do not emit visible light that would distract you and ruin your gaming experience. it is also possible for infrared light to be picked up by the webcam in broad daylight whereas normal LEDs would be overpowered by stray lights. one addition i made was to put a piece of developed but unexposed 35mm film in front of the lens of the webcam to filter out everything but infrared light and it worked spectacularly.

you can tweak the program and set it up to your preference with settings such as deadzone and sensitivity and can save many profiles for use in different games. i won't go through the nitty gritty of how to set it up, but if you're interested there is a handbook on the official website here: http://www.free-track.net/fichiers/manuel21en.pdf

i haven't had any chance to try the TrackIR so i can't compare it with the FreeTrack version, but i'm sure the TrackIR should be more convenient in many ways (especially for people who don't like to DIY).

Project "Sony Playstation 3, 'Phat' White"

so i decided to make a small gamble by getting a faulty Sony Playstation 3 from a seller last week. it suffered from the "yellow light of death" otherwise known as YLOD which is where the indicator light on the unit blinks yellow instead of the usual green colour indicating a hardware failure. while this indicator light does not give specific information on the exact nature of the failure except that it is hardware, it is well known in the Playstation world that the first few generations suffered from a very common hardware failure: dry or cracked solders under the graphics processor (GPU) and/or the main processor (CPU).

basically the older models of Playstation 3's (know as the "phat" version) tend to overheat and the lead-free solders under the GPU and CPU would fail due to the high temperatures. the solders would either become 'dry' or crack, causing a break in connection between the chip and the circuit which then causes the hardware failure and the YLOD. i didn't manage to get a picture of the yellow light but you'll find it easily by googling it.

one of the reasons for this failure is possibly due to a poor cooling system which many people have complained about online. i say possibly because although there have been numerous rants about the default fan in the unit, i found out that it was pretty huge and it was able to move a lot of air through the system. i suspect that the many people that have complained about this might have placed their unit inside an entertainment cupboard or shelf, which basically transforms the shelf/cupboard into an oven.

another reason would be the law that Sony has to follow when it designs a new console, which is that any toy that is sold to a kid cannot contain any form of lead. while this is really great for kids everywhere, leaded solder can withstand higher temperatures than lead-free solder and is better suited for use in the PS3...so...too bad for that...

anyway, there are a few ways to fix a YLOD PS3 but you will require proper equipment. one of the ways is to reflow (melt) the solder under the GPU and CPU and hope they form a new contact where it was previously broken. another way is to remove the GPU and CPU completely and remove the old lead-free solder and replace with leaded solder. the former is much easier than the latter, and in this post i have done the reflow method.

it goes without saying that once you open up the PS3, you'll have to remove the warranty sticker covering the first screw you need to open. it comes off easily, leaving behind many reminders that you have just voided your warranty. since this was a really old unit i had no trouble ripping the sticker right off.

there are quite a number of screws of different sizes so be sure to be clear which screws of which size goes into which hole. the sequence i dismantled the unit shown in the picture above is:

1. blu-ray drive (big box on the right side)

2. bluetooth module (the PCB in the bottom left corner)

3. power supply (box on the top left side)

once those are removed, all that's left is the main PCB itself.

the most tricky part of this procedure is the reflowing itself and my brother did all of the work here because i don't really know how to use this equipment so i came to watch and learn. the board is first preheated to prevent it from cracking from uneven heating like so:

we used a heat gun on the GPU and CPU which pumps out air at 350 degrees celsius. this causes the solders below the chips to melt and reform their contacts with the circuit. the aluminium foil is there to protect the other components around the GPU and CPU from overheating.

after that is done, all that's needed was a new coat of thermal paste and then it was ready to be reassembled.

hooked it up to a television set and....it lives!!

sadly this method is not a permanent fix, as the solders will eventually become dry and crack again one day. but this fix has shown that the problem with the Playstations are indeed due to their faulty solders on the chips.

if you notice that most of the recent posts are all about gaming related stuff, you're spot on...because i'm having my industrial attachment now and i don't have the time to find any antiques to restore...i am planning to do some DIY electronic projects in the coming weeks but that's for later...

Project "Gameboy Advance Cartridge Battery Replacment"

this is a weird but potentially helpful post for people all over the world (if you manage to find this blog in the first place) about how to replace a battery inside a gameboy game cartridge.

i bought this GBA cartridge from a flea market recently and went home to try it. after playing for 5 minutes i saved the game and shut off the player just to see whether the save system works, and it didn't. i assumed that the cartridge was corrupted due to disuse or something like that and intended to throw it away, but i did a quick search online before i tossed it into the bin and i found out something that i didn't know before:

that there is a battery inside the cartridge that actually powers the RAM/EEPROM (or whatever the chip is) inside the cartridge. if that battery ever goes flat, you will be unable to save the game. a friend of mine did mention this to me before but i didn't think it was true because that would mean that one day when the battery does go out the cartridge would be useless, but he was right! i wonder how many people have thrown away perfectly good cartridges when a simple battery change would've done the trick...

i read online that apparently only pirated game cartridges have batteries, but this cartridge came in an original box and the screw that holds the cartridge together is the three pronged kind that comes with original nintendo gameboys, so i'm guessing some original cartridges did use batteries to save games.

anyway, after doing a few minutes research online i found out that the cartridge is powered by a 3 volt battery which is similar (if not exactly the same) as a watch battery. i bought a battery from a hardware store for $2SGD (which is the same price i bought the cartridge for!!) and went about dismantling the cartridge.

the yellow circle you see on the circuit board is the battery and it can be removed by simply removing the solders (with a soldering iron) on the metal contacts like so:

i saw online that they sell new batteries that come with the metal contacts for $10USD++ which is insane. i reused the contacts by ripping them off the old battery, but take note that it requires quite a bit of force as they're stuck to the battery pretty well.

the only problem i faced was that since i reused the metal contacts i had to attach them to the battery somehow. one of the ways i read online was to solder the contact directly onto the battery but i didn't like the idea of exposing a battery to a 200 degree heat source so i jury rigged it by using blu-tack! it was probably the most shoddy work i have ever done so far but hey...it will stick forever unless you throw the cartridge against a wall in which i think a disconnected battery will be the least of your concerns.

i realized that i bought the wrong battery size but it didn't matter in the end because it still fit back into the cartridge. the original battery is CR1620 whereas i bought a CR2025 which is bigger but it's all good...now the battery will last even longer than before.

i powered up the unit with the cartridge slotted in and saved the game before shutting it off. when i turned it on i saw that my savegame was still there so there you go, a simple and easy way of fixing your 'corrupted' cartridge.