The circuit presented here is a modernized version of a stopwatch designed and built by the author several years ago to time equestrian events where the start and stop gates were not readily visible to the timekeepers, necessitating some sort of remote triggering to get reasonable accuracy.

This design uses a single PIC16C55 to generate all the timing and liquid crystal display (LCD) functions. The radio-controlled gating transmitter and receiver sections are comprised of small commercial modules, complete with channel coding/decoding facilities.

Also included is a large display unit so that the audience can be a part of the action -- their hero has two fences to go and the clock is ticking, will he beat the current best time...