Once you have the MPR121 breakout working you'll want to construct electrodes. These are large conductive piece of copper, foil, paint, etc that will act as the "thing you touch"

Remember that electrodes must be electrically conductive! We suggest copper foil tape, conductive fabrics, ITO, pyralux flex PCB, etc. We have tons of great conductive materials in our Materials category. Some can be soldered to, others can be clipped to with alligator chips.

Remember, it doesn't have to be metal to be electrically conductive. Other things that work are tap or salt water, many kinda of food, even fruit!

We suggest soldering a wire to the electrode pad on the breakout and then soldering or clipping it to whatever you want your electrode to be.
The wires and electrodes themselves have a certain amount of 'inherent capacitcance'!

This means that whenever you attach an alligator clip, or a large piece of copper, or whatever your electrode is, the capacitive sense chip will detect it and may think you're touching it. What you have to do is recalibrate the sensor. The easiest way to do that is to restart the python sketch since calibration is done when the chip is initialized. So, basically...

connect all your wires, electrodes, fruit, etc...then start up the capacitive touch program!

This guide was first published on Jul 25, 2014. It was last updated on Jun 18, 2024.

This page (Electrodes) was last updated on Jul 25, 2014.

Text editor powered by tinymce.