I was in Brussels, Belgium for Verbindingen/Jonctions 13 to give a workshop on how to build the GML Recording Machine in collaboration with Evan Roth and Wendy Van Wynsberghe. As you might already know, I started this project with the intention to submit to GML Field Recorder Challenge but couldn’t manage to bring a decent documentation together for the challenge for this actually working device before the deadline. So I did not submit it to the challenge at all. But thanks to Constant for this workshop, there were plenty of people to help for the documentation and thanks to Evan for the great pictures that he took through the building process.
The purpose of the workshop was more creating a documentation for the device than building the device and it took us around 5 hours to build it from scratch. At the end it worked surprisingly in spite of our beliefs that “Electronics projects do not work at first attempt”.
Here is the video by Evan that you can see all the images and the video of the device in action this time in Brussels, (Last time was in Vienna, check it here) :
Here is the complete documentation that you can download in pdf format which is the official how to guide of the device that I finished a bit while after the workshop.
I’ll go through the steps briefly in this post anyway:
The parts that we used to make the device were mostly from Home Depot, and the PS2 ball mouse was from Ebay since it’s not easy to find a ball mouse in stores anymore. There are tape measures, washers, a snap fastener kit, 20ft/6m string, some steel wire, Arduino, Arduino microSD Shield, some resistors, a 9V battery, buttons and some regular tools to make stuff, such as pliers, screwdrivers, soldering iron and solder, Dremmel etc.
On the software side, we need Arduino, Arduino PS2 library to interface the Arduino with PS2 mouse, SDFatLib for interfacing with the Arduino microSD shield, and some programs that I wrote.
We started by modifying the tape measures, we removed the tape from inside and replaced it with a string for each of the measures:
Second and the most time consuming part was modifying the mouse and attach the tape measures and the mouse all together. We cut some parts inside the mouse, drilled holes to put the string through to turn the encoders inside the mouse, modified the discs of encoders, attached some washers to keep the strings on the mechanism. Here are some snapshots from the documentation but be sure to check out the pdf documentation for more details.
The mouse on the right will look like the mouse on the left at the end of this process
Getting rid of some extra parts from inside the mouse.
Cutting some parts of the encoder’s disc in order to decrease the resolution and slow it down since the mouse could not handle the fast rotation by the string. 
Fixing some parts from snap fastener kit to smooth the edges of the plastic and prevent the string cut the plastic as it goes back and forth.
Attaching the mouse and the tape measures all together.
Extending the buttons of the mouse with wires so we can use them as inputs for stroke and calibration.
Then we soldered everything on microSD shield, diagrams are on the pdf documentation, but it’s basically a combination of basic sketches like connecting an LED, connecting a button and tutorial of Arduino PS2 library.
We glued a button to the spray cap to capture the stroke.
Finally we made some modifications on our shoes using the steel wire to be able to attach the strings on our shoes:
And tape everything together make everything stable and colorful. Instead of using tape to attach everything together you can create a case and attach the case to the spray can to be able to replace the can easily.
Briefly, these are the steps, as I said before you can check the pdf documentation for more detailed description of each step.
And again, thanks to Constant and Evan Roth for inviting me to Verbindingen/Jonctions 13 for the workshop and all the participants attended to the workshop so we could document this hard work properly.
