The 433mHz AM beacon was updated. The  Atmel 328p now has its own PCB instead of the “legs-up-beetle” style of previous versions. The further reduce the size of the unit, the 328p board was placed in a sandwich orientation with the transmitter module.

Despite the small size, the board now has a programming port to enable reprogramming of the module.

Below the 433mHz beacon module in front of an Arduino Uno for size comparison.




The radio beacon was designed to allow for extended searches of lost rockets when all other navigational devices have failed (Talking GPS and GPS/SMS tracker). The beacon uses a low power (50mW) AM transmitter operating at 433.92 mHz.

An Atmel 328p running on the internal 8mHz oscillator is powered by a small lipo. The 328p is the only component in the design to minimize size and power consumption. To allow for operation for several days, the 328p produces a short tone (60ms) before going into hibernation for several seconds.

The AM signals are picked up by a velleman RX433 receiver which has an analog output pin. Using a simple yagi antenna and a headset, it is easy to determine the direction and signal strength of the received signals (much better than with FM signals).