Posted: Mon Apr 29, 2019 7:12 pm
I am looking to build a timer for the 40yrd dash for my high school. What would be the best sensors to use for that and what do you think would be the best way to connect the two sensors.
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I doubt that an ultrasonic sensor would have the accuracy or speed for this task. I'd consider a low power laser and a light sensor instead, when the laser beams path is broken on its route to the light sensor, a person has crossed the line.
A break-beam would seem the best option. Or perhaps something which creates multiple break-beams, a wall of beams if one will.
I would suggest a photo-transistor rather than an LDR as it will have a faster response. Again, probably not so much a requirement when it's just for fun.Andyroo wrote: ↑Tue Apr 30, 2019 10:19 amYou could try https://projects.raspberrypi.org/en/pro ... r-tripwire as a starting point?
I would say that regardless what first passes the line (foot, head, ...) that needs to be measured.
It actually comes down to the rules of the sport and the context in which that sport is occurring.