Adafruit
Adafruit 12-Key Capacitive Touch Sensor Breakout - MPR121
The Adafruit MPR121 Capacitive Touch Sensor Breakout provides 12 channels of capacitive touch sensing over I2C. The MPR121 handles all the capacitive filteri...
The Adafruit MPR121 Capacitive Touch Sensor Breakout provides 12 channels of capacitive touch sensing over I2C. The MPR121 handles all the capacitive filtering internally and can be configured for varying sensitivity levels, making it far easier to use than raw analog capacitive sensing.
With four selectable I2C addresses via the ADDR pin, you can connect up to four breakouts on a single bus for a total of 48 touch pads. The board includes a 3V regulator and I2C level shifting for safe use with both 3.3V and 5V microcontrollers, plus an IRQ LED that blinks when touches are detected for easy visual debugging.
Key Features
- 12 Touch Channels – Independent capacitive touch inputs with built-in filtering
- I2C Interface – 4 selectable addresses for up to 48 pads on one bus
- 3/5V Compatible – Onboard 3V regulator and I2C level shifting
- IRQ LED – Visual indicator blinks on touch detection
- Configurable Sensitivity – Adjustable filtering and threshold settings
- Compact Breakout – Pre-soldered MPR121 chip ready for breadboarding
Also Available
- MPR121 Capacitive Touch Shield for Arduino – Shield format with alligator clip pads
Ideal For
- Interactive touch interfaces and control panels
- Musical instruments and touch-based triggers
- Proximity sensing and gesture detection
- Replacing mechanical buttons with touch pads
Package Contents
- 1× Adafruit MPR121 12-key capacitive touch sensor breakout (assembled)
- 1× 0.1" header strip
Specifications
- Sensor Chip – MPR121
- Touch Channels – 12
- Interface – I2C (4 selectable addresses)
- Logic Level – 3.3V or 5V
Jargon buster
Plain-language definitions for the technical terms used above.
- alligator clip
- An alligator clip is a spring-loaded metal clip used to make temporary electrical connections to wires, terminals or test points. It is useful for quick bench testing, but it is less secure than a screw terminal or locking connector.
- 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.
- Shield
- An add-on board that plugs into a main controller board to give it extra features such as sensing, motor control or communication. Knowing a product supports shields helps you judge whether it can connect neatly into an existing maker-board setup.
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Brands
Sensors & Input
Related Tutorials
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