Pi Cap

Turn touch into sound, light or data with your Raspberry Pi.

The Pi Cap is an easy-to-attach add-on board that brings capacitive sensing to your Raspberry Pi projects. It features 12 capacitive electrodes that can be used as touch or distance sensors. Extend each of these electrodes with Electric Paint or other conductive materials to create sensors on a wide range of substrates.

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12 Electrodes

12 capacitive touch and proximity electrodes.

Multi-function button

Button that can be programmed, for example as an off-switch or to control volume.

User-programmable RBG LED

Button that can be programmed, for example as an off-switch or to control volume.

Prototyping area with GPIO breakout

Add more features to the Pi Cap or Raspberry Pi.

3 libraries

Example code and libraries written in C++, Python, and Node.js.

3.5mm audio jack

Adds an audio output to Raspberry Pis that don't have any audio outputs. 

12 high resolution capacitive electrodes

The Pi Cap uses the MPR121 to create 12 capacitive electrodes. You can program the electrodes as touch or proximity sensors, and extend them using Electric Paint or other conductive materials. Use the electrodes to create sensors on a wide range of substrates, from walls, floors, and tabletops to textiles or paper.

Use with Raspberry Pi and Pi Zero

The Pi Cap works both with the Raspberry Pi and the Pi Zero. This means that you can use all of the Raspberry Pi’s features for your capacitive sensing project, like WiFi or Bluetooth.

Technical Information

The Pi Cap is an add on board for the Raspberry Pi A+, B+, 2 B, 3 B and Zero. It features a dedicated capacitive sensing IC, 3.5mm stereo audio output, push switch, RGB LED and prototyping area.

  • Touch IC – Resurgent Semiconductor MPR121
  • Audio output – 15mW into 32Ω via 3.5mm stereo socket
  • Input voltage – 3.3V (via 40-way Raspberry Pi GPIO connector)
  • Input current – 17mA idle, 36mA with all features in concurrent use.
  • Capacitive touch electrodes – 12 (of which 8 can be configured as 3.3V digital I/O)
  • Digital I/O Pins – 7, brought out from 40-way Raspberry Pi GPIO connector – pins 12, 13, 15, 16, 18, 22, 36
  • Push switch – active low momentary push switch connected to pin 7 on the 40-way Raspberry Pi GPIO connector (requires the Pi's onboard pullup resistor to be enabled in software) 
  • Active low, red connected to J8.31 (5mA when on), green to J8.29 (1mA when on), blue to J8.37 (4mA when on)
  • Prototyping area – 84 pads (7 x 12) with 1mm diameter drills spaced 2.54mm apart.
  • Dimensions – 85mm x 40mm x 7mm