I created this project using some old parts from a led controller that died during reprogramming.
After checking a quick test sketch, I found that the new pin change interrupt library works much better and has separate isr functions just like an external interrupt. This meant I could have a full 3x3 keypad with good response and some basic double taps using an Arduino micro, with type c port for the modern feel.
A nice editing layout for coding/3d modeling:
tap/return up. backspace
left. down. right
copy/cut. paste/paste+return. undo
anyways it came out nice so I decided to make a PCB and put it up on kickstarter.
Since its Arduino based I think I should have aimed more at the hackers, so here it is...
It would be really easy to use to control another project and there are still some pwm and analog pins unused.