mini fm transmitter. I think this is the simplest one. Simple, easy and of course cheap. The supply voltage is between 1.1 – 3 Volts with power consumption is 1.8 mA at 1.5 Volts. This circuit should be able to cover 30 meters of range max. at 1.5 Volts.
Technical datas:
Supply voltage : 1.1 - 3 Volts
Power consumption : 1.8 mA at 1.5 Volts
Range : 30 meters max. at 1.5 Volts
Pcb Layout FM Transmitter Mini