# CircuitPython Hardware: MPR121 Capacitive Touch Breakout ## Overview Danger: https://www.youtube.com/watch?v=MUQBCyGYky0 ![](https://cdn-learn.adafruit.com/assets/assets/000/040/213/medium800/sensors_IMG_5750.jpg?1489554984) Reach out and touch somebody or some _thing_ with capacitive touch sensing and the [MPR121 capacitive touch breakout board](../../../adafruit-mpr121-12-key-capacitive-touch-sensor-breakout-tutorial/overview).  Capacitive touch sensing means detecting when something conductive is touched by a large object or person.  For example detecting when a person touches a piece of foil, conductive ink, or even a piece of fruit or a vegetable.  It almost seems like magic but capacitive touch sensing is based on a very simple principle--by touching an object your body slightly changes the capacitance of it and that change can be detected with special circuitry. The MPR121 board is a dedicated capacitive touch sensing chip that can check up to 12 inputs independently for touches.  Since the MPR121 uses a simple I2C interface you can use it with almost any development board like an Arduino, MicroPython or CircuitPython board.  This guide shows how to use the MPR121 capacitive touch sensing breakout with a CircuitPython board. Before you follow this guide it will help to familiarize yourself with the following other guides: - [MicroPython Basics: What is MicroPython?](../../../micropython-basics-what-is-micropython) - [MicroPython Basics: How to Load MicroPython on a Board](../../../micropython-basics-how-to-load-micropython-on-a-board) - [MicroPython Basics: Load Files & Run Code](../../../micropython-basics-load-files-and-run-code) - [Adafruit MPR121 Capacitive Touch Sensor Breakout](../../../adafruit-mpr121-12-key-capacitive-touch-sensor-breakout-tutorial/overview) Continue on to learn about the hardware needed to follow this guide. - [Next Page](https://learn.adafruit.com/circuitpython-hardware-mpr121-capacitive-touch-breakout/circuitpython-wiring.md) ## Featured Products ### Adafruit 12-Key Capacitive Touch Sensor Breakout - MPR121 [Adafruit 12-Key Capacitive Touch Sensor Breakout - MPR121](https://www.adafruit.com/product/1982) 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. The MPR121 has support for only I2C, which can be implemented with nearly... In Stock [Buy Now](https://www.adafruit.com/product/1982) [Related Guides to the Product](https://learn.adafruit.com/products/1982/guides) ### Adafruit 12 x Capacitive Touch Shield for Arduino - MPR121 [Adafruit 12 x Capacitive Touch Shield for Arduino - MPR121](https://www.adafruit.com/product/2024) This touch-able add on shield for Arduinos will inspire your next interactive project with 12 capacitive touch sensors. Capacitive touch sensing works by detecting when a person (or animal) has touched one of the sensor electrodes. Capacitive touch sensing used for stuff like touch-reactive... In Stock [Buy Now](https://www.adafruit.com/product/2024) [Related Guides to the Product](https://learn.adafruit.com/products/2024/guides) ### Adafruit Feather M0 Basic Proto - ATSAMD21 Cortex M0 [Adafruit Feather M0 Basic Proto - ATSAMD21 Cortex M0](https://www.adafruit.com/product/2772) Feather is the new development board from Adafruit, and like its namesake it is thin, light, and lets you fly! We designed Feather to be a new standard for portable microcontroller cores. This is the  **Feather M0 Basic Proto** , it has a bunch of prototyping space... In Stock [Buy Now](https://www.adafruit.com/product/2772) [Related Guides to the Product](https://learn.adafruit.com/products/2772/guides) ### Adafruit Feather HUZZAH with ESP8266 - Loose Headers [Adafruit Feather HUZZAH with ESP8266 - Loose Headers](https://www.adafruit.com/product/2821) Feather is the new development board from Adafruit, and like its namesake, it is thin, light, and lets you fly! We designed Feather to be a new standard for portable microcontroller cores. This is the  **Adafruit Feather HUZZAH ESP8266**  - our take on an... Out of Stock [Buy Now](https://www.adafruit.com/product/2821) [Related Guides to the Product](https://learn.adafruit.com/products/2821/guides) ### Adafruit HUZZAH ESP8266 Breakout [Adafruit HUZZAH ESP8266 Breakout](https://www.adafruit.com/product/2471) Add Internet to your next project with an adorable, bite-sized WiFi microcontroller, at a price you like! The ESP8266 processor from Espressif is an 80 MHz microcontroller with a full WiFi front-end (both as client and access point) and TCP/IP stack with DNS support as well. While this chip... In Stock [Buy Now](https://www.adafruit.com/product/2471) [Related Guides to the Product](https://learn.adafruit.com/products/2471/guides) ### Arduino Zero - 32 bit Cortex M0 Arduino with Debug Interface [Arduino Zero - 32 bit Cortex M0 Arduino with Debug Interface](https://www.adafruit.com/product/2843) With the new **Arduino Zero** , the more creative individual will have the potential to create one’s most imaginative and new ideas for IoT devices, wearable technologies, high tech automation, wild robotics and other not yet thinkable adventures in the world of... No Longer Stocked [Buy Now](https://www.adafruit.com/product/2843) [Related Guides to the Product](https://learn.adafruit.com/products/2843/guides) ### Small Alligator Clip Test Lead (set of 12) [Small Alligator Clip Test Lead (set of 12)](https://www.adafruit.com/product/1008) Connect this to that without soldering using these handy mini alligator clip test leads. 15" cables with alligator clip on each end, color coded. You get 12 pieces in 6 colors. Strong and grippy, these always come in handy! We often use these in conjunction with a multimeter so we... Out of Stock [Buy Now](https://www.adafruit.com/product/1008) [Related Guides to the Product](https://learn.adafruit.com/products/1008/guides) ### Small Alligator Clip to Male Jumper Wire Bundle - 12 Pieces [Small Alligator Clip to Male Jumper Wire Bundle - 12 Pieces](https://www.adafruit.com/product/3255) For bread-boarding with unusual non-header-friendly surfaces, these cables will be your best friends! No longer will you have long strands of alligator clips that are grabbing little wires. These compact jumper cables have a premium male header on one end, and a grippy mini alligator clip on... Out of Stock [Buy Now](https://www.adafruit.com/product/3255) [Related Guides to the Product](https://learn.adafruit.com/products/3255/guides) ## Related Guides - [Adafruit Feather HUZZAH ESP8266](https://learn.adafruit.com/adafruit-feather-huzzah-esp8266.md) - [3D Printed Case for Adafruit Feather](https://learn.adafruit.com/3d-printed-case-for-adafruit-feather.md) - [Manually bridging MQTT to Adafruit.IO](https://learn.adafruit.com/manually-bridging-mqtt-mosquitto-to-adafruit-io.md) - [MicroPython Basics: ESP8266 WebREPL](https://learn.adafruit.com/micropython-basics-esp8266-webrepl.md) - [CircuitPython Hardware: PCA9685 DC Motor & Stepper Driver](https://learn.adafruit.com/micropython-hardware-pca9685-dc-motor-and-stepper-driver.md) - [Adafruit NeoPXL8 FeatherWing and Library](https://learn.adafruit.com/adafruit-neopxl8-featherwing-and-library.md) - [MicroPython Hardware: I2C Devices](https://learn.adafruit.com/micropython-hardware-i2c-devices.md) - [ESP8266 Temperature / Humidity Webserver](https://learn.adafruit.com/esp8266-temperature-slash-humidity-webserver.md) - [Debugging the SAMD21 with GDB](https://learn.adafruit.com/debugging-the-samd21-with-gdb.md) - [MicroPython Basics: How to Load MicroPython on a Board](https://learn.adafruit.com/micropython-basics-how-to-load-micropython-on-a-board.md) - [CircuitPython Powered AT Hand-Raiser](https://learn.adafruit.com/at-hand-raiser.md) - [CircuitPython Hardware: PCA9685 PWM & Servo Driver](https://learn.adafruit.com/micropython-hardware-pca9685-pwm-and-servo-driver.md) - [OOZE MASTER 3000: NeoPixel Simulated Liquid Physics](https://learn.adafruit.com/ooze-master-3000-neopixel-simulated-liquid-physics.md) - [Introducing Adafruit Feather](https://learn.adafruit.com/adafruit-feather.md) - [Capacitive Touch Drum Machine](https://learn.adafruit.com/capacitive-touch-drum-machine.md) - [Fair Weather Friend: Internet-Connected Migraine or Allergies Detector](https://learn.adafruit.com/fair-weather-friend-internet-connected-health-and-leisure-forecaster.md)