Capacitive Paint Controller

I have been playing with Bare Conductive paint since it came out a little more than a year ago.  It’s great stuff – a heavy acrylic paint that can be used as a resistor, touch sensor, paintable wire – and I keep coming up with new uses for it.  This idea stemmed from wanting to utilize my modular synth in more of an installation setting than a performance music setting.

I think of this as a sort of “sonic self-portrait.”  Two 10″x10″ canvases painted yellow with my hand prints painted in conductive paint.  A small piece of copper tape is attached to the back of each canvas and connected to Arduino.  Code on the Arduino turns the canvases into capacitive sensors and sends two channels of 0-5V PWM voltage out through RC filters into the modular synthesizer.  In short: touch the painting, send modulations to the synthesizer.

The Arduino sketch uses Paul Badger‘s CapSense library.  I had to use an older build of the Arduino programmer (alpha 22) in order to get the library working.  You can find the most recent version of the code here: GitHub.  Circuit and patch descriptions below the audio.

Circuit Description:

• For capacitive inputs, 22MΩ resistors were used between the paintings and the inputs of the Arduino (digital pins 2 and 5)
• CV out was taken from digital PWM pins 9 and 10 from the Arduino.
• PWM outputs were smoothed to modular-friendly 0-5V CV using simple RC filters (10kΩ resistor and 0.01uF cap)

Patch description:

• Left-hand CV to:
  • MATHS Ch 1 Signal In
    • Ch 1 set to Log, Rise and Fall at ~1 o’clock
    • MATHS Ch 1 CV to Optomix Ch 1 control in (Hertz Donut audio), Wogglebug Heart in
  • MATHS Ch 2 Signal In
    • Sum out to A-132-3 (Wogglebug FM’d Dixie audio), OR out to Echophon Depth
• Right-hand CV to:
  • Piston Honda CV in
  • Piston Honda Hither/Yon CV ins
  • A-119 Asymetrical Input
    • Take gate out to MATHS Ch 4 Trig input
    • MATHS Ch 4 set to Lin, Rise CCW, Fall at ~12 o’clock
    • MATHS Ch 4 to Optomix Ch 2 strike in (Piston Honda audio), HD modulation index, EOC to Wogglebug clock in
• Wogglebug clock out to Echophon Tempo in
• Single Audio output from Echophon → TC Electronic Hall of Fame Reverb