Datasheet

0x5D

cap.begin(0x5A)

begin() returns true if the sensor was found on the I2C bus, and false if not.

Touch detection

99% of users will be perfectly happy just querying what sensors are currentlt touched. You

can read all at once with

cap.touched()

Which returns a 16 bit value. Each of the bottom 12 bits refers to one sensor. So if you want

to test if the #4 is touched, you can use

if (cap.touched() & (1 << 4)) { do something }

You can check its not touched with:

if (! (cap.to uched() & (1 << 4)) ) { do something }

Raw Data

You can grab the current baseline and filtered data for each sensor with

filteredData(sensornumber);

baselineData(sensornumber);

It returns a 16-bit number which is the number of counts, there's no unit like "mg" or

"capacitance". The baseline is initialized to the current ambient readings when the sensor

begin() is called - you can always reinitialize by re-calling begin()! The baseline will drift a bit,

that's normal! It is trying to compensate for humidity and other environmental changes.

If you need to change the threshholds for touch detection, you can do that with

setThreshholds(uint8_t touch, uint8_t release)

By default, the touch threshhold is 12 counts, and the release is 6 counts. It's reset to these

values whenever you call begin() by the way.

https://learn.adafruit.com/adafruit-mpr121-12-key-capacitive-touch-

sensor-breakout-tutorial

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