As a maker I convert units all the time, fractional to metric, tenths to metric, MPH to KPH etc. In this video I build a dedicated desktop calculator that can do all of my conversion at the twist of a knob and the punch of a few keys. I will be using the Arduino UNO, a rotary encoder, an LCD character display and a bunch of Cherry MX switches to build this. It is designed in a way that it can be easily replicated and built at home. New conversions are easily added with a software update!
The main home for this project is on the Element14 Community. There you can find the BOM (Bill of Materials), updates, the build video and discussions with myself and the community about this build.
Element14 Connumity Project Page
This is a pretty normal Arduino install. Just fire up the the Arduino IDE, configure it for your board and compile/upload.