Hardware

The examples in this guide are no longer supported. Check out the MPR121 sensor guide for CircuitPython and Python usage: https://learn.adafruit.com/adafruit-mpr121-12-key-capacitive-touch-sensor-breakout-tutorial/overview

Parts

You'll need the following parts to build this project:

Wiring

Place the MPR121 board into a breadboard and connect its inputs to the electrodes you plan to use.  Then follow the wiring below for your platform to connect the MPR121 to an I2C communication channel.

Raspberry Pi

On a Raspberry Pi connect the hardware as follows.

Note: Make sure you've enabled I2C on your Raspberry Pi!

  • Connect Raspberry Pi 3.3V to MPR121 VIN.
  • Connect Raspberry Pi GND to MPR121 GND.
  • Connect Raspberry Pi SCL to MPR121 SCL.
  • Connect Raspberry Pi SDA to MPR121 SDA.

BeagleBone Black

On a BeagleBone Black connect the hardware as follows.  If you aren't familir with how pins are numbered on the BeagleBone Black be sure to read this guide first.

  • Connect BeagleBone Black 3.3V pin P9_3 to MPR121 VIN.
  • Connect BeagleBone Black DGND pin P9_1 to MPR121 GND.
  • Connect BeagleBone Black I2C2 SCL pin P9_19 to MPR121 SCL.
  • Connect BeagleBone Black I2C2 SDA pin P9_20 to MPR121 SDA.

Once the hardware is connected to your development board, continue on to learn how to install the software for this project.

This guide was first published on Dec 23, 2014. It was last updated on Dec 23, 2014.
This page (Hardware) was last updated on Aug 08, 2020.