IQRF Traffic Lights for BMX

Today, we are going to tell something about wireless traffic lights for BMX races. Here it is necessary to control a pair of riders, so they does not enter both on the track simultaneously to avoid collision. This traffic lights alternately allows to enter one of drivers to track, then 10 seconds is red color on both devices (entrances) and then driver from the second entrance is allowed to enter the track.

Traffic light hardware is very simple:

  • TR module TR-52DC (connector for external antenna).
  • CAB-U.FL/SMA cable.
  • SMA external antenna.
  • Two general purpose NPN transistor, for example BC817.
  • Red and Green LEDs.
  • Resistors 4k7.
  • Resistors 330R.
  • Battery (from mobile phone for example).
  • Jumper.


TR-52DC modules allows to connect external antenna thanks to CAB-U.FL/SMA cable. Device is enclosed in simple plastic box with holes for LEDs and antenna connector. Master/slave configuration is done by software way.


Full source project for IQRF IDE is attached.

Written by Tomáš Novotný

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