Capacitive sensor 12-key, MPR121

MPR121 Capacitive sensor with 12 channels to bring capacitive interface to your DIY projects

Add many touch sensors to your next project driven with microcontroler or Raspberry-Pi with the MPR121. The MPR121 is an easy-to-use 12-channel capacitive touch sensor assembled on a breakout board. The MPR121 can handle 12 individual touch pads.

The I2C bus is used to communicate with the MPR121, so it can be implemented with nearly any microcontroller. The MPR121 (and the breakout) offer up to 4 addresses with the ADDR pin (up to 48 capacitive touch pads on a single I2C).

Thank to this chip is a lot more easier to build capacitive touch sensor than using the analog input: the MPR121 can handles all the needed filtering for you and can also be configured in touch sensitivity (more or less sensitivity).

The MPR121 is a 3V based sensor, Adafruit did added 3V regulator and level shifter for I2C communication... so the breakout is safe to use with 3V or 5V microcontroller (Arduino or Pyboard). The IRQ line have a LED so it will blink when a touch is detected on any pad (making debugging more easier).

The breakout is shipped assembled an tested. A section of pinHeader is included in the package. You can solder the pinHeader on the breakout if you want to plug it on a breadboard.

Getting started with the breakout is easy and libraries are available for Arduino, MicroPython and Nano-computer.

Technical details

• Dimensions: 33mm x 19mm x 2mm
• Weight: 2.2 gr
• Uses I2C 7-bit address 0x5A (can be set to 0x5B, 0x5C or 0x5D)
• Datasheets, PCB files and Fritzing object available in Adafruit's tutorial