Capacitive touch button driver module MPR121, I2C

Product detailed description

The MPR121 capacitive touch button driver module allows you to easily expand your project with up to twelve touch electrodes controlled via a single I²C bus. The chip performs filtering and automatic calibration independently, so the microcontroller only needs to read the status of individual channels or be notified via an interrupt on the IRQ pin. In addition to touch, the MPR121 can evaluate proximity using a simulated thirteenth electrode. If channels ELE4–ELE11 are not used as touch electrodes, they can be configured as general-purpose GPIOs or outputs for LED control. The module is suitable for touch keyboards, control panels, musical instruments, or hidden switches under a non-conductive surface (glass, plastic, wood).

Specifications:

• Chip: MPR121 (NXP / Freescale)
• Supply Voltage: 2.5–3.6 V DC (typically 3.3 V)
• Logic Level: 3.3 V (use a level shifter for 5V systems)
• Communication: I²C (up to 400 kHz)
• I²C address: 0x5A (default)
• Number of capacitive channels: 12 (ELE0–ELE11)
• Proximity sensing: yes, simulated 13th electrode (proximity detection)
• Number of LED / GPIO channels: 8 (ELE4–ELE11, if not used as electrodes)
• Measurement resolution: 10-bit
• Interrupt: IRQ output (active low) – eliminates the need for continuous polling
• Power Consumption: approx. 29 µA (normal operation), approx. 3 µA (stop mode)
• Pins: VCC, GND, SDA, SCL, IRQ, ELE0–ELE11
• Dimensions: 20.5 × 31 mm
• Compatibility: Arduino, ESP32, ESP8266, Raspberry Pi and other MCUs with I²C (Adafruit MPR121 library recommended)

Package contents:

• 1× MPR121 Capacitive Touch Button Driver Module, I²C

Note:

• Electrodes can be created using a conductive surface (PCB copper, conductive tape, a nail, conductive ink) even under a non-conductive cover – the thickness and material of the cover should be considered when adjusting the sensitivity.
• This product is not a standalone functional unit and may require professional installation.
• Product images are for illustrative purposes only and may sometimes differ from the actual appearance of the item. However, this does not change their basic properties.