/diy/ - Do It Yourself

How small can you make an FM radio? This RDA5807M looks pretty damn good and it's damn cheap (I assume the headphones here act as the antenna, which is neat). But it does require a connected MCU (I think) and is tuned externally. The KT0913 looks even better since it has an optional pot for tuning(?), but it shows those I2C pins going to a micro in an example circuit. What are these microcontrollers used for? I guess I can just slap an ATTiny there and an encoder if I just need it for selection and a few buttons, but it really seems like something that could easily be integrated into the IC itself.

Looks like these things pull about 20mA at 2-3V, and I'll add 50mA extra for driving the headphones themselves. This gives about 0.18W, or about 7 hours on a AAA-size Li-ion. 0.8W is trivial to get with solar, if you're so inclined.