David Goldberg
Game Trak Rev1
Game Trak Rev2
gesticular hardware controler as a musical interface
Game Trak
In 2018, I first saw Rebecca Fiebrink present her software Wekinator at a talk in London. She was using the (then unknown to me) Playstation 2 controller called Game Trak. This controller was originally designed for golf & fighting games where the controller works as an external gesticular input source. After that, I saw the controller from time to time in my Youtube research, especially during performances of the SLORK (Stanford Laptop Orchestra). They used several of these controllers to play custom programmed instruments in Chuck.
The principle is relatively simple and may be considered cumbersome from today's point of view as it is basically a 2 X 3 axis joystick where the Z-axis is defined by an extendable nylon string with a return mechanism. Since no video explains exactly how the controller is called, you have to search a little more to find out which obscure device it is.
Since this project didn't get out of my head I searched again and again at different intervals and then finally found it.
The Gametrak controller was released for Xbox, Ps2 and PC and it would have been easiest to buy the PC version because it doesn't require any further hacking and is immediately recognized as a USB device on the computer. Unfortunately, this version is also the rarest and I couldn't find any of them, so I decided to buy a console version.
Since there are several revisions of this controller and not for all revisions a suitable manual can be found on DIY forums, it was very frustrating to start this project.
I had to buy 2 controllers because I couldn't find out which DIY documentation is valid for which revision.
The following revisions are available for the PS 2 Game Trakk controller:
Rev 1 (best version for hacking as you only need to change one solder joint)
Rev 1 V2 ( requires Arduino or Microcontroller but offers enough space to store it)
Rev 2 ( requires Arduino or Microcontroller and you have to build your own case) ( The version I use)
These controllers are fortunately not very expensive and currently, there is still a good availability which makes this DIY project also suitable for beginners.
Hacked Game Trak
Since I had some experience with Supercollider and MAX Msp but had not yet done a complete project with Arduino/ Teensy, the well-documented pages of Gareth Young and Anoujeremia came in handy and I will link to them at the end of this page. All in all, I spent a bit more money on it than described on DIY forums, which I attribute to the increasing popularity of this hardware hacking project.
This is not a stepbystep tutorial on how to build this mod, it's more documentation of my use-cases for the controller.
Please head to the mentioned hacking descriptions for further instructions.
Things you need for the built:
Gametrak: 25,- €
Teensy: 35,- €
Soldering iron
Solder
Wire Stripper
Breadboard
Precision Mechanics for electronics.
In the above-mentioned talk of Rebecca Fiebrink, she uses the controller in interaction with the software Wekinator developed by her which serves for the simple learning of neuronal networks. In the example, she uses the Max Library PeRColate and more specifically the object Blotar~.
By loading the midi streams (axes x/y/z) from Gametrak into Max and converting them into OSC data, she can store any number of parameters and their settings. Wekinator then allows you to interpolate between these stored parameters, which, depending on the mapping, can generate extremely unconventional sounds. The addition that the Blotar Object is a physical modeling engine makes the Game Trak seem like the perfect interface, as the haptic feel and weight of the return mechanism allow it to mimic an almost acoustic playing experience. The Gametrak sends out 6 parameters in this example and these have to be mapped to the OSC streams of Wekinator in Max. However, these parameters can represent completely different categories depending on the instrument.
Wekinator then stores the radius of the different parameters through which you can interpolate with your gestures.
With this flexibility the Game Trak could also be a great companion in a performance piece where dancers can control light and sound with it.
In the example of the Stanford Laptop Orchestras, the GameTrak functions on a more conventional level, representing individual instruments as in an orchestra. In this particular, the Slork has now released dozens of instruments for the Gametrak and has also held several large concert performances with it.
But since you can also control conventional midi data with it, you can also use the Gametrak as a spatialization controller. More specifically, in this case I used the great IEM tools from the University of Graz to place various instruments binaurally in space.
It is also conceivable that this controller can be used to control a multichannel sound system.
Game Trak & Wekinator Controlling Blotar Max Object
Additionally I have built a patch in Supercollider that can be played with the Game Trak. This is again a physical modeling patch but without a neural network. But it is possible to play chords.
Due to the gliding movements of the game trak, very strong accelerandos can be interpreted here. In addition, you can play quantized intervals with the Gametrak in a previously defined scale. This allows you to play the controller in a jam context without being a theremin virtuoso.
A technical manual and script description can be found here in the Supercollider Patch !
Spatial Control / Binauraly Rendered.
Please use Headphones