I would like to build a lane judge for my local cubs pinewood derby, something like this: http://newdirections.ws/index.htm . It is a three lane track so it needs to show 1st and 2nd, 3rd can just be blank, in the form of either different coloured LEDs or on a 7-segment display.

I need help with a circuit diagram for this project as my knowledge of electronics is too small at the moment. I can probably work out how to build it from a circuit digram.

I hope I have explained it well enough, any help would be appreciated.

PS. The fewer ICs the better, I currently only have a couple of 555 timers and 741 op-amps but can get others if needed.

 

This website appears to have a fair design in play. You can at least use it as a starting point in furthering this discussion.

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