Hello,
I'm developing an open source calculator. So far it has RPN/algebraic entry, scientific functions, complex numbers and is programmable. The next step is to develop a keypad that plugs into the BoosterPack connectors and a power supply to turn it into a hand held.
See the following video:
https://www.youtube.com/watch?v=Ev7-7Hwkang
EDIT: I've placed this in the wrong category on the forum. Moderators please delete this post.