April 10, 2007

Finally, here are the pictures!



After many late nights of drilling, soldering, gluing and cursing, the guitar hero controller is done! Well, at least until I decide to start tweaking it again…


For those if you who don’t know the story, here is a brief description of the events that led us here:

1) I became an obsessive player of the Guitar Hero games for the Playstation 2 console. These games do a great job of making you feel like you are really playing amazing guitar licks with the real bands. I was going to work each day with my hand aching and curled up in the “claw” position.

2) The Playstation 3 came out and was supposed to be able to play PS2 games, but alas, there was no way to connect the Guitar Hero controllers to it.

3) I ripped the PS2 out of my entertainment center anyway, and installed the shiny new PS3. Even the lower resolution PS2 games look much better on it, because I play on a very large screen with about 50 feet of video cable in my ceiling, going to an overhead projector. The PS3 output looks far less grainy and blurry on this setup.

4) It turns out that you can play Guitar Hero on the PS3 using the handheld wireless PS3 game controllers. I remembered that some guys from the guitar hero message boards had converted their original PS2 guitar controllers to wireless (before a wireless version was available) by stuffing the guts of a handheld wireless PS2 controller into the body of a guitar hero controller.

5) It occurred to me that I could do the same thing with a wireless PS3 controller, but I thought “Why not go all the way and stuff it in the body of a real guitar? How hard could that be? I bet I could bang that out in no time!”

6) After many, many late nights of drilling, soldering, gluing and cursing, it finally works!

The first guitar I chose for the project was actually a new Stratocaster that had been damaged and needed some repair. After coming quite close, I could not bring myself to start cutting on it. So I fixed it and it plays beautifully (thanks Guitar Center dude, I’m sorry I didn’t use it after all your help). So I went back out on a pawn shop hunt and found this black Chinese Strat knock-off with the brand name “Drive”. Sixty bucks later I was ready to start cutting:




The “Drive” guitar looks exactly like a Strat cosmetically. I never actually played it, but you can feel that it is quite a bit lighter than a Strat. On the inside, it is much more cheaply made, with no shielding and a lot of stuff permanently glued that you could normally take apart. I never figured how to get the neck off, which definitely would have made things easier.

I started out with a lot of different ideas about how to make the buttons. My first attempt involved taking the soft buttons out of a touch-tone phone because I was looking for much lighter action than the original controller buttons. I actually went through the phone section of the electronics store, trying out the feel of the various buttons. I was turning the phones on their side and wailing away on them like I was playing a guitar. It was hard not to wag my tongue a little while I did this, which generated some strange looks from the other customers.

When I first test fit the buttons from the phone that I had selected, I didn’t really like the way that it felt, because they were round buttons that were quite a bit smaller than the original controller buttons. I decided that what I really wanted was the good ol' big plastic color-coded buttons. I used a Dremel tool to cut out the shapes of the buttons in the frets of the guitar.

I tried to use the actual button sensor circuit from the Guitar Hero controller, but it wasn’t really working out, so I decided I had to design something from the ground up.


I found some very small surface-mount micro-switches that felt like they would be sensitive enough for the feel I was looking for. Then to get the support structure for the big button caps, I made a little plastic board and foam sandwich to contain the switch (note the remnants of the sacrificial “Got Beer?” coozie).



One of the things that was always a pain with the buttons was that I had to do everything 5 times. Here they are ready to go in:



I decided to mount the buttons with a pair of very small set-screws. The buttons all turned out a little bit different in terms of the action required to activate the switch, so the screws allowed me to pre-load the buttons to just the right height. The idea was that just the slightest touch would activate the switch. The caps fit over the screws and don’t make contact with them.


To get the wires in the body, I decided to gouge a slot in the back of the neck and fill it back in later. If I had been able to take the neck off and somehow get the damned truss-rod out it, would have made perfect wireway. Instead, I had to grind on the truss rod to get the buttons deep enough and never really got quite as deep as I wanted.




To keep the rest of the electronics assembly detachable, I added a 10-pin ribbon connector:




Here is an early picture from when I was working on the strummer switch:


To install the strummer switch, I removed the middle pick-up and once again, built a custom micro-switch-and-foam sandwich that is activated by the rocker button from the guitar hero controller. If you are familiar with guitar pick-ups, you know that the screw-mounts on either end are spring loaded so that the pick-up height can be adjusted from the outside. I used this same basic concept to mount the strummer assembly, so that I can adjust the switch sensitivity from the outside. As I tighten the screws at the edges of the pick-up, a plate compresses the foam so that the button action gets lighter. This has turned out to be very useful as I have been figuring out how I like it set up.

Finally, here is a view of the guts of the controller (click here for a larger view)

I wanted everything to be mounted to the pickguard for easy removal and repair. As you can see, I soldered everything to the back of a connector on the PS3 controller board. This connector is for the flexible printed-circuit sheet that would normally sit under the PS3 controller buttons. The buttons basically switch the +2.6 power supply voltage to logic inputs via pull-up resistors that are printed on the flex sheet. I soldered replacement resistors to the connector.
I used the pickup selector switch for the all-important “PS3” button as well as the “Start” button. The buttons are activated by rocking the selector switch all of the way to either side.

The battery is mounted under the circuit board. The USB charging connecter faces outward and is accessed via a hole in the side of the guitar. The fret-button connector is on the right and the “Star-power” tilt sensor is the little circuit board on the left with the red and black wires.

You can also see the two joysticks with little shafts sticking up and the Bluetooth radio which is the large square metal sub-assembly on the top right.

The last big challenge was to get the tremolo or “whammy bar” working. The left joystick functions as the tremolo when playing with the hand-held controller. I decided to create some kind of mechanism in the body of the guitar to capture the top of the joystick and tug on it when the real tremolo of the guitar was depressed.




The tremolo normally has 3 big springs to counteract the force of the strings, but with the strings off I had to remove 2 of the springs to make the tremolo easier to press.

So finally it all basically works. Here it is, charging up, next to the old controllers (with our old custom paint jobs):



So, How Well does It Play????

First of all, after all of the work, I have to say it is a good feeling just to pick it up, switch on the “PS3” button and watch it successfully make the Bluetooth link (you can see the blinking red lights through the charging cable hole). It easily navigates the game menus and functions perfectly in that regard.

Also, it is very cool to walk around with it, feeling like you are holding a real guitar (which it is)! I chose the fret position of the buttons because I wanted the arm extension and hand position where you would typically be playing chords. The down side is that the buttons are farther apart and it is definitely harder to play. My original fantasy had been to include a second set of “solo” buttons down close to the body but I just got too burned out from all of the work. In spite of the light button action, I still tend to overdrive the buttons down into the foam and wind up with the carpal-tunnel “Claw” after I have been playing. I can still complete songs on the “expert” level, but I honestly haven’t explored it much yet.

If I were going to start all over again, there are many things I would do differently. For starters I would put the whole thing up on an mill for all of the cutting. I also think it might be better to directly mount a trim-pot to the tremolo and wire it in place of the joystick (I might still go back in for that one, we’ll see).

For now I am just going to play with it for a while. I’ll keep you posted if anything interesting develops.

Click the comment link below to let me know what you think!


P.S. Thanks to the guys that did the original PS2 wireless mods. I learned some important things from them (such as the fact that the left and right D-Pads buttons need to be soldered closed for the controller to function in "guitar-mode", where a strum is required in conjunction with a button push).