DIY Folding Keyboard Perfect for Typing on the Go

When Apple announced the first iPhone, I made a very misguided prediction: I said that it would never be successful because people wanted physical, tactile keyboards. I couldn't have been more wrong about that and, like everyone else, I now use a smartphone that is all touchscreen. But a real keyboard is still superior when you need to do more than tap out a quick text or email. For text-heavy situations, Sergei Silnov designed this DIY folding keyboard called crabapplepad.

When folded up for storage, crabapplepad is roughly the size of a man's hand and quite thin. It is small enough to fit in a pocket if you aren't wearing skinny jeans. When unfolded for use, it gives the typist a split-style keyboard with a set of 42 mechanical keys. Silnov needed to be able to type with a Cyrillic layout, so 42 keys were necessary to accommodate that. This is an intentionally minimalist device, so crabapplepad doesn't have any additional features, like LEDs or multimedia knobs. But it does have magnets for attaching an Apple Magic Trackpad, which eliminates the need for a separate mouse.

Inside the 3D-printed enclosure is a custom PCB designed by Silnov. That hosts a Seeed Studio XIAO nRF52840 development board that has a built-in BLE (Bluetooth Low Energy) adapter for connecting to a PC, smartphone, or tablet. To keep the device as slim as possible, Silnov chose Kailh X mechanical key switches. The key caps were 3D-printed to be very thin. Those and the enclosure (including the hinge) were designed in Autodesk Fusion 360.

If the crabapplepad interests you, you can find all of the files on GitHub to build your own.