Raspberry Pi Pico PCB uses all 26 pins in custom capacitive touch sensor

Raspberry Pi
(Image credit: Tom Fox)

The Raspberry Pi Pico is a very handy microcontroller with plenty of GPIO pins to tinker with. Each of these pins is designated to a particular protocol but none of that matters to maker and developer Tom Fox. In his latest project, Fox demonstrates another useful yet somewhat primitive feature of these pins. Fox has created a custom PCB he calls Spoke that turns all 26 pins on the Pico into an individual touch sensor.

Initial Spoke tests - YouTube Initial Spoke tests - YouTube
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According to Fox, the idea began when he first realized that he could use a 1M resistor to transform one of the GPIO pins on the Pico into a touch-sensitive input sensor. Understanding resistor values can be tricky, our Decoding Resistors reference guide is handy to keep around when working on projects like these. From there, he took the idea and ran with it, going so far as to create a custom PCB to better prototype with the idea.

We're no strangers to creating a touch-input device on the Pico. We even put together our own guide on how to create a banana-based touch input device. However, you can do so much more with this idea than just play around with fruit and Fox demonstrates that well. He suggests it could help people create things like accessibility devices or tools for professional environments that require testing with prototype work.

Fox has provided a few actual examples of what he's been using it for and we definitely like the flexibility it brings. Spoke has been implemented as a USB to MIDI interface and has even acted as both a keyboard and mouse HID. The musical possibilities are intriguing and well demonstrated in this video shared on YouTube.

The hardware used in this project consists of the custom Spoke PCB designed by Fox and a Raspberry Pi Pico. Beyond that, all you need is anything that brings your imagination to fruition. For example, Fox created a beautiful housing for his instrument demo with tall rods that you touch to activate different notes.

If you want to get a closer look at this Raspberry Pi project, you can check it out in greater detail over at Hackster.

Ash Hill
Contributing Writer

Ash Hill is a contributing writer for Tom's Hardware with a wealth of experience in the hobby electronics, 3D printing and PCs. She manages the Pi projects of the month and much of our daily Raspberry Pi reporting while also finding the best coupons and deals on all tech.