I got my hands on an old cash register, and salvaged it for the keypad. I decided to make it into a hotkey keyboard for my computer, which turned out really well! The final product has lots of greek letters which it types by executing a shortcut ( ALT + 230 = µ), plus some other shortcuts, which will be very helpful for lab reports! I then made a fancy box to put it in. I'm quite happy with the end product!
I used a knock-off Arduino Pro Micro to detect when a key has been pressed, then to send emulated keystrokes to the computer it's attached to! (via USB) This works on any computer, plug and play.
See the code at: https://github.com/fwacer/hotkeyboard
Detailed blog post: https://brycedombrowski.com/2019/08/summer-2019-custom-hotkey-ke