June 2016
Does anyone have a schematic for a pinewood derby finish line race timer? I would prefer to build something that doesn’t use a microcontroller, if at all possible.
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Try this link www.techlib.com/electronics/games.html it might be usefull with a little change in switches.
When my grandchildren were into Pinewood Derby racing, I built a “which came first” circuit. The system has two 12 volt lamps mounted above the track at the end. The car that breaks the beam causes the lamp to light and locks out the other track. A tie is not possible.
A 12 volt, center tapped transformer supplies 5 VDC to the logic and 12 VAC to the lamps. The logic consists of nand gates and set-reset flipflops. When one FF is set, it energizes a relay that lights the lamp and simultaneously locks out the other channel.
A 38 or 40 khz IR transmitter is mounted above the track at the end and the receiver is mounted under the track (or vice versa). You may be able to find a receiver at RadioShack, Ebay, or Amazon. The receiver is 38khz but 40khz will work fine. I used reed relays that will work on 5 volts but any 5 volt relay will work. My original system included a three digit timer but 8 to 10 year olds are not interested in the time.
