The MPR121QR2, a capacitive touch sensor controller, simplifies the integration of capacitive touch sensing into your projects. Facilitating communication via I2C, this sensor controller measures the capacitance of twelve electrode points. When an object approaches the electrode connector, causing a change in capacitance, the MPR121 recognizes a touch event. Notably, this versatile IC can also drive LEDs or offer basic GPIO functionality on electrode pins 4 through 11, providing flexibility in project customization. Operating within a voltage range of 1.71V to 3.6V, the MPR121QR2 consumes minimal power, drawing only around 29 µA when sampling every 16 milliseconds.

Features:

1. Capacitive Touch Sensing: Measures the capacitance of twelve electrode points. Detects touch events when an object approaches the electrodes.

2. Voltage Range: Operates within a voltage range of 1.71V to 3.6V. Adaptable to various power supply configurations.

3. Low Power Operation: Consumes low power, with a supply current of 29 µA at a 16 ms sampling interval. Stop mode current is as low as 3 µA.

4. Multifunctional Inputs: Eight inputs support multifunctionality for the LED driver and GPIO. Offers versatility in configuring LEDs and general-purpose input/output.

5. Touch Detection Features: Auto-configuration for each sensing input. Auto-calibration for each sensing input enhances accuracy. Touch/release threshold and debounce settings for precise touch detection.

6. I2C Interface: Communicates via I2C, providing a standardized and efficient communication protocol. Features an interrupt output for timely notifications.

7. Temperature Range: Operates within a wide temperature range of -40°C to +85°C. Suitable for a variety of environmental conditions.

Specifications:

• Supply Voltage: 1.71V to 3.6V
• Supply Current (Sampling Interval): 29 µA
• Stop Mode Current: 3 µA
• Number of Sensing Inputs: 12
• Multifunctional Inputs: 8 (for LED driver and GPIO)
• I2C Interface: Yes, with Interrupt output
• Temperature Range: -40°C to +85°C

How to Connect and Program with Arduino:

1. Connectivity:

   • Utilize the I2C interface for communication.
   • Default slave address is 0x5A (ADD to GND).

2. Programming:

   • Several Arduino libraries are available for ease of use.
   • Recommended library: MPR121 Arduino Library.  

Applications:

• Human-Machine Interface:

  • Incorporate touch sensing in user interfaces for interactive devices.
  • Ideal for buttons and controls in electronic systems.

• Interactive Projects:

  • Enables touch-based interaction in various electronic projects.
  • Suitable for creative installations and exhibits.

• Low Power Applications:

  • Well-suited for battery-operated devices due to low power consumption.
  • Extends battery life in portable electronics.

• Sensor Networks:

  • Integration into sensor networks for touch-based data acquisition.
  • Provides a tactile dimension to sensor networks.

• Educational Demonstrations:

  • Valuable for educational purposes to demonstrate capacitive touch technology.
  • Facilitates hands-on learning in electronics.