Rotor-Racing manual lap-count buttons

thingiverse

I used these spotter buttons at Weston Park Dronefest 2017, which proved to be incredibly useful during the event. Many modern race control software packages, such as Laps Free from RCTiming.com, allow you to quickly simulate competitors crossing the finish line by using your keyboard keys or manually register missed laps in case a competitor's transponder is not functioning properly. They can also be easily made from common components and used when high-end lap timing systems are too expensive.