MPR121 Capacitive Touch Sensor Module

MPR121 Capacitive Touch Sensor Module is a powerful breakout board that empowers you to add up to twelve independent capacitive touch electrodes to your projects. This highly versatile module makes it easy to turn almost any non-conductive material into an interactive interface. Hobbyists and developers frequently use it for creating touch-sensitive buttons, sliders, and controls in robotics, wearable tech, and user interface designs.

Key Features:

• Up to 12 Electrodes: Gain unparalleled control with 12 independent, configurable touch electrodes for multi-point interaction.
• I²C Interface: Communicate with any microcontroller using a standard two-wire I²C interface, simplifying wiring and code.
• Auto-Calibration: The module automatically recalibrates itself to handle environmental changes and reduce false triggers, ensuring reliable performance.
• Individual Thresholds: Set a unique touch and release threshold for each electrode, allowing you to fine-tune sensitivity.
• Low Power Operation: Operates at low current, making it ideal for battery-powered or energy-efficient applications.
• Interrupt Pin: An integrated IRQ pin can signal your microcontroller when a touch event occurs, freeing it from continuous polling.

Technical Specifications:

• Operating Voltage: 1.71 V to 3.6 V (typical 3.3 V)
• Interface: I²C (up to 400 kHz)
• Number of Electrodes: 12 (configurable)
• Current Consumption: ~29 µA (Active), ~3 µA (Standby)
• Output Data Rate: Up to 3.125 Hz
• Operating Temperature: −40 °C to +85 °C

Mechanical Specifications:

• Module Type: Breakout PCB with soldered MPR121 IC and passive components.
• Connector: Standard 0.1″ (2.54 mm) pitch header pins.
• Assembly: Designed for breadboard prototyping and jumper wire connections.
• Material: FR4 PCB with silkscreen labeling.

Dimensions:

• Board Length: ~20 mm
• Board Width: ~18 mm
• Pin Pitch: Standard 2.54 mm for breadboard compatibility.

Pinout and Wiring:

• VCC: Power supply (3.3V typical for the chip).
• GND: Ground.
• SCL: I²C Clock line.
• SDA: I²C Data line.
• IRQ: Interrupt Request output pin.
• ADD: I²C Address select pin (connect to GND for address 0x5A, VCC for 0x5B, etc.).
• Wiring Note: Simply connect the power pins and the I²C lines to your microcontroller. Connect your touch electrodes (wires, foil, conductive fabric) to the E0-E11 pins.

Datasheet Reference:

• Consult the official NXP MPR121 datasheet for complete electrical specifications, register details, and advanced configuration settings.

Applications:

• Interactive Interfaces: Create touch-sensitive controls on furniture, walls, or other objects.
• Robotics: Use as a touch-based bumper or proximity sensor.
• Wearable Devices: Build gesture-based controls into clothing or accessories.
• Smart Home Automation: Implement custom touch panels for lighting or appliance control.
• Proximity Sensing: Detect the presence of an object without physical contact.

Equivalent Models:

• TTP223: A single-channel capacitive touch sensor IC.
• TTP229: A simple multi-channel capacitive touch sensor.
• FDC1004: A high-resolution capacitance-to-digital converter.

Package Includes:

• 1 x MPR121 Capacitive Touch Sensor Module