This small transmitter can send its signals to a receiver placed at distances up to 100 m. The coil is formed by 4 turns of 22 to 26 AWG wire in a air core with 1 cm of diameter, The antenna is a piece of solid wire 10 t0 30 cm long. The circuit is powered from common cells. Equivalent to the transistor can be used such as the 2N2222.
FM Micro Transmitter
