MPR121 Capacitive Touch Sensor has support for only I2C, which can be implemented with nearly any microcontroller. You can select one of 4 addresses with the ADDR pin, for a total of 48 capacitive touch pads on one I2C 2-wire bus. Using this chip is a lot easier than doing the capacitive sensing with analog inputs: it handles all the filtering for you and can be configured for more/less sensitivity.
This sensor comes as a tiny hard-to-solder chip so we put it onto a breakout board for you. Comes with a fully assembled board, and a stick of 0.1″ header so you can plug it into a breadboard. For contacts, we suggest using copper foil or parallax, then solder a wire that connects from the foil pad to the breakout.
Add lots of touch sensors to your next microcontroller project with this easy-to-use 12-channel capacitive touch sensor breakout board, starring the MPR121. This chip can handle up to 12 individual touchpads.
Features and Specifications – MPR121 Capacitive Touch Sensor
- 1.71 V to 3.6 V operation
- 12 electrodes
- I2C interface, with optional IRQ output to advise electrode status changes
- LED driver functionality with a maximum of 8 LEDs
- Uses I2C 7-bit address 0x5A (can be set to 0x5B, 0x5C or 0x5D)
Features: MPR121 Capacitive Touch Sensor
• 1.71V to 3.6V operation
• 29 μA typical run currently at 16 ms sampling interval
• 3 μA in scan stop mode current
• 12 electrodes/capacitance sensing inputs in which 8 are multifunctional for LED driving and GPIO
• Integrated independent autocalibration for each electrode input
• Autoconfiguration of charge current and charge time for each electrode input
• Separate touch and release trip thresholds for each electrode, providing hysteresis and electrode independence
• I2C interface, with IRQ Interrupt output to advise electrode status changes
• 3 mm x 3 mm x 0.65 mm 20 lead QFN package
• -40°C to +85°C operating temperature range Implementations
• General Purpose Capacitance Detection
• Switch Replacements
• TouchPads, Touch Wheel, Touch Slide Bar, Touch Screen Panel
• Capacitance Near Proximity Detection.
Applications: MPR121 Capacitive Touch Sensor
• PC Peripherals
• MP3 Players
• Remote Controls
• Mobile Phones
• Lighting Controls