I am using Sparkfun's MPR121 breakout board with an Arduino to sense proximity/touch to a number of electrodes. There are long (~10m) shielded wires running to the electrodes, which are aluminum tape under 1 or 2 mm of foam. I am using the code from bildr's MPR121 tutorial.
I have to set the touch threshold to 0x01 in order to trigger the sensor, and then I get lots of false positives, and false release triggers too.
Before using the MPR121, I was just using the
capsense() library with the example code and 10M resistors and found I could get fairly reliable results for two sensors, but I thought that by using the breakout, I could reliably, and possibly more quickly, get data from 12 sensors.
Are there changes I could make to the arduino code that would help me? or is there a place on the breakout where I could add a stronger resistor and increase the sensitivity as was the case with the capsense example?