Datasheet

Electrodes
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.
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!
The wires and electrodes themselves have a certain amount of 'inherent capacitcance'!
© Adafruit Industries
https://learn.adafruit.com/adafruit-mpr121-12-key-capacitive-touch-sensor-breakout-
tutorial
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