Small breakout based on Freescale's MPR121QR2 chip, a capacitive touch sensor, controlled via an I²C interface. The chip can individually control up to 12 electrodes and a maximum of 8 LEDs (when they are not configured as electrodes). At the bottom of the printout, there are 4 jumpers (pitches with track), all closed by default. A jumper connects the ADD pin to the ground, so the I²C address of the chip will be 0x5A. The jumpers also connect the SDA, SCL and IRQ pins to the 10 Kohm pull-up resistors. The breakout does not have a voltage regulator, so the power supply must be between 2.5 and 3.6 Vdc. Weight: 3 grams.

• Schematic
• Eagle Files
• Datasheet (MPR121QR)
• Example Code (ATmega328)
• Hookup Guide
• Freescale’s Product Page (for Application Notes, etc.)
• Bildr Tutorial
• GitHub​