If you're thinking of doing the same thing with a wireless controller, beardawg252002 has done just that over at the Xbox-Scene forums.
The name, Gyokusho is actually stolen from a japanese chess variant called Shogi. The equivalent of the king is called the Gyokusho or "Jade general". The short hand for that is the sign you can see in the middle of the controller (see image below).
Oh, and by the way, it's huge.
Step 1: The Disassembly
1 = A
2 = B
3 = X
4 = Y
5 = LB
6 = RB
7 = Back
8 = Start
9 = Left analogue stick click
10 = Right analogue stick click
Left analogue stick represents the analogue directions
X/Y axis are controlled by the right analogue stick and finally, the Z-axis is controlled by the left and right trigger. Right trigger increases X whereas the left one decreases it. Nice and simple.
I removed all the screws holding the 360 controller together, unplugged the vibration motors and presto, you've got yourself a nice and tidy circuit board. You don't have to use much force when doing this, if you can't get it open, you've probably overlooked the screw that sits under the sticker.
Removing the triggers takes a bit of effort but it can be done. Just make sure that the lever that's left is tied to the construction holding it (I just used some stripped wires and wound them around the plastic since superglue didn't do the trick). If you don't do this, the levers will move around and you'll probably get unwanted readings.
Step 2: Shiny New Buttons
A: they work and
B: you solder the ground and the "closed"-pin, otherwise your button will always be active until it is depressed (and nobody likes a sad button).
Here are the images, enjoy.
Step 3: Woodwork
The following images are just there to show you how it can be done. I cut the board, used screws to hold it together, ground down the edges and then I used plaster to cover up the... er... unexpected features. OK, mistakes. There, I said it.
Many a sandpaper had to be sacrificed for this to become what it is today.
Oh, and if you have a better place to do this in than the kitchen of a small apartment, use it.
Step 4: Paintjob
Giving it the black base coat wasn't all that hard, I just used some spray paint and all of a sudden, it was black. The letters were what caused me all that trouble.
I took a piece of clear plastic film, I cut out the letters that I wanted and then I tried to use white spray paint. Unfortunately, all that happened was that capillary action reared its ugly head and turned the letters into blobs. I covered it up with a new coat of black and I hand painted the letters with a different kind of paint. It turned out quite well. Until I wanted to clear coat it that was.
When I had sprayed the whole contraption with clear paint, the hand painted bits started to dissolve before my eyes. I cursed and screamed but then I just thought to myself that at least you can see what it says. Perhaps I'll do it right someday (yeah right).
Step 5: Gentlemen, Start Your Soldering Guns
These shots are here to illustrate how I mounted the microswithces to the buttons.
If you are thinking of doing this yourself, remember to use several different colours of cable since this makes it so much easier when something turns brown.
Step 6: Soldering the Buttons to the Circuit Board
Now it's time to bring out the finest soldering tip you have since this requires a fair amount of precision.
Below are some images of how to connect the RB/LB-buttons as well as the A/B/X/Y/Start/Back/Guide-buttons.
As you can see, I had to cut off some pieces of plastic that covered the solering points for RB/LB but a Dremel and a steady hand gets the job done.
When you solder the A/B/X/Y/Start/Back/Guide-buttons you'll have to carefully scratch off the black stuff that covers the copper. I tried to solder the cables on without scratching but it just wouldn't stick. A word of caution though, don't scratch too hard or you'll remove the whole thing, copper and all and if you happen to expose one of the other cables running next to these soldering points, make damn sure that you don't short-circuit between them. A multimeter is your best friend here.
Step 7: Soldering the Directions
Instead I had to retrace the wires leading to and from the directional soldering points and where they went straight through the circuit board, I had to scratch off the resin-like substance that covered the copper, peel the thinnest cable I could find, then run it straight through and then solder it in place. The greatest problem with this was that the cables snapped when the isolation wasn't there to protect it. Also, since the circuit board was already mounted in place, I had to use a mirror under the circuit board to try and find the right hole, get the cable through and then have a little stand hold the cable in place without snapping it while I soldered it in place. That was one of the hardest things I've ever done when it comes to soldering.
Also, since the way thin cables snapped so easily, I had to use the slightly thicker ones to connect to the buttons and then solder the two together.
For slightly larger photos you can visit my Flickr-page.
Step 8: All Done
I added a latch so that the bottom of the contraption would stay shut when it was on the table and then it was done.
I have been thinking of warm-glueing some optic cables to the LEDs that show you which controller number you have, drilling some holes around the Guide-button and then sit back and watch the pretty lights but I probably won't bother. It's actually quite nice to have a controller that doesn't glow.
Some day I will implement the LT/RT, after all it's just to put a resistor of some appropriate size on one cable and then have one cable that leads to the ground and there you would have eliminated the potentiometer but I just can't be bothered. It's quite good enough as it is.
Some of you may have noticed that I had drawn Playstation-symbols on the controller, that's because I'm thinking of going for a dual-system kinda thang. Perhaps some rainy day I'll do that.