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Jun 08, 2023

Turning Tact Switches Into Keyboards

One of the great unsolved problems in the world of DIY electronics is a small

One of the great unsolved problems in the world of DIY electronics is a small keyboard. Building your own QWERTY keyboard is a well-studied and completely solved problem; you need only look at the mechanical keyboard community for evidence of that. For a small keyboard, though, you’d probably be looking at an old Blackberry handset, one of those Bluetooth doohickies, or rolling your own like the fantastic Hackaday Belgrade badge. All of these have shortcomings. You’ll need to find a header for the Blackberry keyboard's ribbon cable, the standard Bluetooth keyboard requires Bluetooth, and while the Belgrade badge's keyboard works well, it's a badge, not a keyboard you would throw in a bag for years of use.

[bobricious] might have just cracked it. For his Hackaday Prize entry, he's created a tiny USB keyboard out of tact switches. What's the secret? An entire panel of PCBs. It looks great, and it might just hold up to the rigors of being tossed in a random bag of holding filled with electronics.

The electronics for the keyboard are simple enough; there are 56 standard through-hole tact switches, and an SAMD21 microcontroller. Connections to the outside world are through a micro USB port, serial, or I2C. it's small, too, coming in at just under 5 cm by 10 cm.

The real trick here is using a stack of PCBs to label the buttons and provide a bit of mechanical support. The panel for this project consists of one base board holding all the electronics and a secondary board that gives the entire project a finished look while adding a bit of structural support.

If you’ve never looked at the options for small keyboards, there aren't many. Blackberries are a thing of the past, and there's no good way to add a QWERTY keyboard to small projects. This project does that in spades. Since the basic idea is, ‘put holes in a second PCB’, this idea is transferable to other keyboard layouts too.