This Arduino Unit Conversion Calculator Is a Must-Have for Every Maker
Kaleb Clark designed a dedicated desktop calculator that converts units with the twist of a knob and the punch of a few keys.
While you can argue about which unit is best for what situation, the reality is that unit conversion is a part of life for anyone that spends a lot of time making things in the shop. Interestingly, a dedicated unit conversion calculator isn't really standard equipment, meaning that we have to make do with pulling out a phone, scrawling notes on a piece of paper, or — if you’ve been at it for years and years — simply rattling off figures from memory.
element14's Kaleb Clark, however, decided to make his own conversion device using an Arduino Uno and Cherry MX switches as the primary input method. These 20 switches are hand-soldered together in a matrix arrangement, providing space for 0-9 and basic math functions. A rotary input on the top of the unit switches between conversion types, and up/down arrows are meant to "ramp up" from mm to cm, meters, etc. and down again.
This clever up/down input is not currently implemented in the code, but shouldn’t be that tough to add on. Output is via a nice 4x20 LCD character panel, and the whole thing has a nice “beefy” look to it, that should appear at home on your workbench or desk.