Print A Flexible Keypad

[Micah Elizabeth Scott] needed a custom USB keyboard that wrapped around a post. She couldn’t find exactly what she wanted so she designed and printed it using flexible Nijaflex filament. You can see the design process and the result in the video below.

The electronics rely on a Teensy, which can emulate a USB keyboard easily. The keys themselves use the old resistor divider trick to allow one analog input on the Teensy to read multiple buttons. This was handy, but also minimized the wiring on the flexible PCB.

The board itself used Pyralux that was milled instead of etched. Most of the PCB artwork was done in KiCAD, other than the outline which was done in a more conventional CAD program.

We always enjoy seeing practical use of hacker-grade 3D printers. After all, there are only so many keychains you can make. Of course, you probably don’t need exactly this keyboard layout. But the techniques of creating the flexible PCB, printing the keypad itself and integrating everything with the electronics would be a great road map for any similar project.

As far as we can tell, the cat made no actual contribution to the final design. Unless you count inspiring flexibility, perhaps.

We’ve seen people make the actual PCBs using Pyralux and Ninjaflex as an etch resist if you don’t want to mill the boards. This isn’t the first time we’ve seen a Teensy pressed into keyboard controller service, either.

Thanks [Kyle] for the tip.

8 thoughts on “Print A Flexible Keypad

  1. Nice, but for a hap’orth of tar… Why not rotate the switches ~45deg so you get rid of the steps in the traces, and put the resistors in the ‘natural’ path of the trace?

  2. I was a bit confused reading this the first time, I thought the nijaflex [sic] WAS the flexible printed circuit, as that was all the top photo showed, and I followed the link and discovered that I was mistaken.

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