Description This is a breakout board for Freescales MPR121QR2 The MPR121 is a capacitive touch sensor controller driven by an I2C interface The chip can control up to twelve individual electrodes as well as a simulated thirteenth electrode The MPR121 also features eight LED driving pins When these pins are not configured as electrodes they may be used to drive LEDs There a four jumpers on the bottom of the board all of which are set closed by default An address jumper ties the ADD pin to ground meaning the default I2C address of the chip will be 0x5A If you need to change the address of the chip by shorting ADD to a different pin make sure you open the jumper first Jumpers also connect SDA SCL and the interrupt pin to 10K pull up resistors If you dont require the pull up resistors you can open the jumpers by cutting the trace connecting them There is no regulation on the board so the voltage supplied should be between 2 5 to 3 6VDC The VREG pin 2 5 and is connected through a 0 1uF capacitor to ground which means unless you modify the board you cant operate the MPR121 in low supply voltage mode 1 71 2 75VDC Package included 1 x MPR121 Breakout v12 Proximity Capacitive Touch Sensor Board