Attributes

Brand	-
Category	Robotics / STEM Teaching Tools / Sensors
Origin	-
Chip Model	MPR121
Interface Protocol	I2C (Inter-Integrated Circuit)
Input Channels	12 Capacitive Touch Electrodes
Operating Voltage	3.3V to 5.5V DC
Communication Address	0x5A (Default, configurable)
PCB Dimensions	24mm x 18mm
Connector Type	2.54mm Pitch Header Pins
Compatibility	Arduino, Raspberry Pi, ESP32, STM32
Touch Sensitivity	Adjustable via Software Registers
Package Includes	1x MPR121 Board, 1x Pin Header Strip

6 reviews

Anonymous

Mar 25, 2026

Rating: 5/5

Perfect for DIY Macro Pads

This board works flawlessly with my Arduino Pro Micro project. The I2C communication is stable, and the sensitivity adjustment allows me to detect touches even through a thin acrylic layer. Highly recommended for custom keyboard builds.

Anonymous

Mar 15, 2026

Rating: 4/5

Great value, needs careful wiring

The sensor itself is excellent and very responsive. I deducted one star because the pinout diagram on the back is slightly faint, so make sure you check the datasheet before soldering. Once connected, it worked immediately.

Anonymous

Mar 15, 2026

Rating: 5/5

Reliable for student projects

We bought ten of these for our robotics club. Students found the libraries easy to use, and the boards have survived multiple re-wiring sessions without any issues. Excellent durability for the price point.

Anonymous

Mar 13, 2026

Rating: 4/5

Good documentation support

The hardware is solid. I had some initial trouble with address conflicts when using two sensors, but the online community examples helped me resolve it quickly by changing the ADDR pin settings.

Anonymous

Mar 02, 2026

Rating: 5/5

Exceeded expectations

I was worried about noise interference, but the built-in filtering on the MPR121 chip handles it well. It detects gloved touches reliably, which was a specific requirement for my industrial control panel prototype.

Anonymous

Mar 01, 2026

Rating: 5/5

Low latency touch detection

Impressed by how fast the response time is. There is virtually no lag between touching the electrode and the signal being sent over I2C. Perfect for creating interactive art installations or musical instruments.

5 FAQ

Q: What is the maximum thickness of material that can cover the touch pads?

A: While dependent on sensitivity settings and material dielectric properties, the sensor typically works well through up to 3-5mm of plastic, glass, or wood. Calibration is recommended for thicker materials.

Q: Does this come with pre-soldered headers?

A: No, the board is shipped with a separate strip of header pins to allow you to choose the orientation (straight or right-angle) that best fits your project enclosure.

Q: Is there a library available for ESP32?

A: Yes, several open-source libraries are available on GitHub and the Arduino Library Manager that support the ESP32 platform. Search for 'MPR121' to find compatible options.

Q: How do I change the I2C address if I need to connect multiple boards?

A: You can change the I2C address by connecting the ADDR pin to VDD, GND, or SDA through specific resistors as detailed in the NXP MPR121 datasheet. This allows up to 4 devices on the same bus.

Q: Can this board be used directly with 5V logic without a level shifter?

A: Yes, the MPR121 module operates comfortably within the 3.3V to 5.5V range, making it directly compatible with 5V microcontrollers like the standard Arduino Uno.

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