MPR121 Breakout V12 Capacitive Touch Sensor Controller Module – 12-Channel I2C Touch Keyboard

Product Description

The MPR121 Breakout V12 Capacitive Touch Sensor Controller Module is a compact touch-sensing board designed to add capacitive touch functionality to Arduino, ESP32, and other compatible microcontroller projects.

Powered by the MPR121 capacitive touch controller IC, this module supports up to 12 independent touch electrodes and one simulated thirteenth electrode for proximity sensing. It communicates with a microcontroller through the I2C interface, making it easy to build touch-sensitive buttons, control panels, touch keyboards, and interactive electronic projects.

The module also features 8 LED-driving pins, which can be used to control LEDs when they are not assigned as touch electrodes. Onboard jumper connections provide 10K pull-up resistors for the SDA, SCL, and interrupt lines. The default I2C address is 0x5A.

Its compact design makes it suitable for DIY electronics, interactive installations, smart control panels, and educational projects.

Key Features

• 12 Capacitive Touch Inputs: Supports up to 12 individual touch electrodes.

• 13th Simulated Electrode: Provides proximity-sensing functionality through electrode configuration.

• I2C Communication: Simple two-wire communication with compatible microcontrollers.

• 8 LED-Driving Pins: Can be configured for LED control when not used as touch electrodes.

• Default I2C Address: 0x5A, configurable through the ADD connection.

• Onboard Pull-up Resistors: 10K pull-ups for SDA, SCL, and interrupt connections.

• Compact Design: Small PCB suitable for embedded and DIY electronics projects.

Technical Specifications

Jumper Configuration

The module has four jumper connections on the bottom of the PCB:

• ADD Jumper: Connects the ADD pin to GND for the default I2C address of 0x5A. Open the jumper before selecting a different address connection.

• SDA Jumper: Connects the SDA line to its onboard 10K pull-up resistor.

• SCL Jumper: Connects the SCL line to its onboard 10K pull-up resistor.

• INT Jumper: Connects the interrupt line to its onboard 10K pull-up resistor.

The jumpers are closed by default. If external pull-up resistors are already being used, the onboard pull-ups can be disconnected by cutting the corresponding PCB traces.

Applications

• Capacitive touch buttons and switches

• Arduino and ESP32 touch projects

• DIY touch keyboards and control panels

• Smart home control interfaces

• Interactive art and electronic installations

• Touch-based lighting control

• Proximity detection experiments

• Educational electronics and STEM projects

Compatibility

Suitable for use with compatible microcontrollers and development boards, including:

• Arduino boards

• ESP32 development boards

• Raspberry Pi and other I2C-compatible controllers

Important: The module operates at 2.5V–3.6V. Ensure that the I2C signal levels are compatible with the module. Do not directly connect 5V I2C signals unless suitable level shifting is used.

Package Includes

1. 1 × MPR121 Breakout V12 Capacitive Touch Sensor Controller Module

2. 1 × 6-Pin Male Header

3. 1 × 12-Pin Male Header

Important Notes

• The default I2C address is 0x5A.

• The module requires compatible I2C wiring and suitable controller libraries.

• Touch electrodes may require calibration and tuning depending on the electrode size, wiring, and surrounding environment.

• Header pins may require soldering before use.

• Verify the actual PCB jumper layout and pin labels before making connections.