The Keybow MINI PCB has a 40-pin female header, like a regular pHAT, that plugs onto the 40-pin male header on the Raspberry Pi Zero W. The Pi is attached to the acrylic baseplate, and the whole thing is rigidly held together by metal standoffs. Rubber feet on the baseplate stop Keybow MINI from slipping around on your desk.
Keybow MINI comes with your choice of Kailh Speed Gold (clicky) or Silver (linear, non-clicky) switches. Both switches are light and smooth, and the gold switches have a satisfying click when pressed.
We've chosen clear DSA key caps for Keybow MINI, as they show off the per-key RGB LEDs really well. The slightly frosted finish on the clear key caps diffuses the light beautifully. Being DSA, the caps have a flat profile that suits the small size of Keybow MINI.
The switches slot into the PCB switch plate to hold them securely, and then push into the Kailh hot-swap sockets on the Keybow MINI PCB. This means that there's no soldering required, and you can easily change out the switches in the future, if you wish.
Note that if you want to use different switches with Keybow MINI, then you'll need to ensure that they have a recess on the underside for surface-mount LEDs.
We've used the same tiny APA102 RGB LEDs that we use on our Picade Plasma PCBs, and there's one under each of the three keys. The LEDs sit in the cavity on the underside of the switch and shine up through, into the key cap.
There's a nifty way to light and animate the LEDs on Keybow MINI. You can create a PNG file with a coloured gradient or pattern, and it will be animated across the LEDs from the top of the image to the bottom. The width of the PNG determines how it's displayed.
You can manually set the LEDs on one or more keys, overriding the animation, or have them only light up when pressed.
There's a bunch of example animations to use, or you can create your own in your favourite graphics program.
Key mappings and layouts
The power of Keybow MINI is in how customisable it is. You can map each of the three keys to whichever keyboard keys you want, or even have them trigger a whole series of keypresses or strings of text to be entered.
Our Keybow software uses the on-the-go micro-USB port on the Raspberry Pi Zero W and USB HID gadget mode, so that it appears as a regular USB keyboard device when plugged into a computer.
The custom, stripped-down OS runs on a RAM-disk, meaning that it boots and runs quickly, it's robust against being unplugged, and there's no risk of SD card corruption.
To customise your Keybow MINI layout and lighting, just pop the micro-SD card out and edit the keys.lua file on your computer.
Note that you'll need to add
keybow.use_mini() to the setup function in your key layout file to remap the keys to Keybow MINI's smaller layout, and use
handle_minikey_xx for the name of each mapped key's function.