This following is re-post of an article from my old blog from 2008: This is an FM radio transmitter I made using an arduino and a NS73M FM Transmitter. I got the idea from an article on hack a day, if you’re interested in building your own you should check out Mike Yancey's page he built the one that made it on hackaday.com and he does a very thorough job of documenting how all the components hook together. I was impressed by the level of finishing he was able to achieve on the housing; it looked like a commercial product. I wanted to see if I could achieve a similar result, it’s amazing what you can do with some simple hand tools. If your patient with the file, you can make perfectly square holes in aluminum. On my implementation I omitted the de-bouncing circuit that he has connected to his rotary encoder, and I used a two-line display. Since I omitted the de-bouncing circuit, I couldn’t use the original rotary encoder library since that code uses a hardware interrupt a...