RF Relay Sequencer 4 ports/3 events

Event sequencer for proper RX to TX transmition, and the return to RX mode. This sequencer based on modern STM32F0 CPU. Internal CPU clocking guarantees high precision and long-term stability, no capacitors, no external timing network, everything is digital. Sequencer has four high current MOSFET switches on output, they’re switching in 3 step (stage) with delay. Delay time can be selected by onboard jumper from two values – 15ms or 45ms. Three of MOSFET output port is “OPEN DRAIN” and “ground” active – OUT1, OUT2 and OUT3. Fourth MOSFET output port has external DC +12-30 input line (IN+) that switched ON (to OUT+ line) in TX mode and has same timing diagram as OUT3.
Output ports not protected, just bare DRAINS, so – be careful, don’t forget to use diodes in parallel with relay coils.
Sequencer can be switched to TX or RX mode by external footswitch only (active state – ground).


  • Board size is 70 x 45 mm
  • Output ports: 4 ports, 50v/3a max
  • Input ports: Footswitch (active state – ground)
  • Delay time: 15 ms or 45 ms, onboard jumper selectable
  • DC input: 5-12VDC, >0.1A
  • Weight: 50g

Cost: 15USD