As I mentioned in a previous post, I first built a pedal to control my Pd patch to create live effects for my guitar by using a hacked gamepad.
After using it for over a year, I started being dissatisfied with the low precision of the analog inputs (audible in Pd), as well as with the limited number of inputs available (some weren’t working because it was a cheap gamepad).
A few email to the pd-list helped me decided to build another pedal based on a Arduino Uno board.I choosed the Uno because of its price (around 25 Euros), its small size (about 5 x 8 x 1 cm), and because it has 6 analog pins (for potentiometers) and 14 digital pins (for buttons). I needed 8 buttons to trigger effects and 1 pot for the expression pedal, so that was enough for me.
Here’s a list of the tools and electronic parts I used to build my foot controller :
- soldering iron with thin tip + soldering wire,
- some wire (with multiple thread, or it will break),
- stand with crocodile clips (it’s cheap and it’ll make your life some much easier),
- solderable breadboard,
- 5kOhm linear potentiometer(s),
- momentary button(s) (“push” button with only one position, like in arcade machines. Make sure they’re big enough to be pushed by the foot),
- resistor(s) between 1K and 10KOhm (one per button).
- + everything needed to build the case and the expression pedal (drill, wood, Lego parts, balanced jack cable and female plugs, etc.).
After a few days’ work (or weeks’, because I have a job…), here’s what I ended up with :
The mechanics in the expression pedal were made with Lego parts. The cable between the expression pedal and the main pedal is a balanced (stereo) jack cable, because the pot in the pedal needs 3 wires. Here’s a close-up :
And finally, the inside :
Once the pedal was finished I had to figure out how to install the Arduino IDE, upload firmata, and use Pduino to let the pedal send data to Pd.