This may sound unreal but this works. Three component FM transmitter probably is the simplest transmitter in the world. Ant the count of components can be reduced to two. This is because there are one Attiny45 chip and couple coin batteries – total three. If using one battery this makes two component FM bug.

So where is the magic in all of this? Sprite_tm likes to dig much deeper in to inner structure of AVR. It appears that Internal RC oscillator is using PLL which allows getting different clock speeds. RC oscillator works at 8MHz and in order to get 16MHz internal clock 8MHz is multiplied by eight and then divided by 4. By tweaking internal RC calibration register he managed to overclock chip to 24MHz. This means that PLL is running at 96MHz which is withing FM range. By playing with calibration register he was able to get FM modulation. Without any external antennas range is limited but this works. Hardly practical but fun to try.