Adafruit
Adafruit MPR121 12-Key Capacitive Touch Sensor Gator Breakout - STEMMA QT / Qwiic
The Adafruit MPR121 Gator Breakout adds 12 capacitive touch inputs to any microcontroller project — no soldering required. With large alligator/croc-clip fri...
The Adafruit MPR121 Gator Breakout adds 12 capacitive touch inputs to any microcontroller project — no soldering required. With large alligator/croc-clip friendly pads and STEMMA QT / Qwiic connectors, simply clip conductive materials to the pads and plug into your board's I2C port.
The MPR121 handles all capacitive touch filtering and threshold detection internally over I2C, making it far simpler than reading analog inputs directly. Two selectable I2C addresses (via the ADDR solder jumper) allow up to 24 touch pads on a single bus. The breakout includes a 3.3 V regulator and level shifting for compatibility with both 3.3 V and 5 V systems, plus an IRQ LED that blinks on touch detection for easy debugging.
Key Features
- 12 Capacitive Touch Channels – Each with its own large gator-clip pad
- MPR121 Touch Controller – Built-in filtering and configurable sensitivity
- I2C Interface – 2 selectable addresses for up to 24 pads on one bus
- STEMMA QT / Qwiic Connectors – Solderless I2C connection (cable not included)
- 3.3 V and 5 V Compatible – On-board regulator and level shifting
- IRQ LED Indicator – Blinks when a touch is detected
- No Soldering Required – Clip conductive materials directly to the oversized pads
Ideal For
- Interactive art and music installations
- Custom touch-sensitive controllers and keyboards
- Educational projects exploring capacitive sensing
- Costume and wearable touch interfaces
Package Contents
- 1× Adafruit MPR121 12-Key Capacitive Touch Gator Breakout (assembled)
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- breakout
- A breakout is a small circuit board that makes a tiny or hard-to-solder component easier to connect to with standard pins. It matters because this OLED module can be wired into a microcontroller project without needing to solder directly to the display’s fine contacts.
- capacitive sensing
- Capacitive sensing detects changes in electrical capacitance, in this case caused by different amounts of water in the soil near the sensor plate. It matters because it avoids exposed metal probe contacts, which can corrode in damp soil over time.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- IRQ
- Short for interrupt request, a signal pin a device uses to get a microcontroller’s attention when something needs handling. It matters here because I2C communication with the sensor requires connecting the IRQ pin to a suitable input pin.
- LED
- A light-emitting diode is a small electronic component that lights up when current flows through it in the correct direction. In this kit, LEDs create the flashing effect, so polarity and correct soldering matter for the project to work.
- microcontroller
- A microcontroller is a small computer on a chip that runs your program and controls connected inputs and outputs. For this product, it is the part that reads buttons and sensors, drives the display and speaker, and communicates over Bluetooth.
- Qwiic
- Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.
- solder jumper
- A solder jumper is a small pair or group of pads on a circuit board that can be bridged or cut with solder to change a hardware setting. It matters because changing modes may require careful soldering rather than just changing software.
- STEMMA
- A plug-and-cable connection system used on some maker electronics boards to make wiring simpler. If a product uses STEMMA, you need the matching cable or connector type to plug it in without soldering.
- STEMMA QT
- A small plug-in connector system for I2C boards that lets you connect compatible sensors and controllers without soldering. It matters because it can make wiring faster and less error-prone, especially when adding several small modules to a project.
Find this product in
Brands
Sensors & Input
Related Tutorials
Free guides on learn.littlebird.com.au
