# Speed trap for straightaway speed



## nate.wagner (Feb 11, 2014)

Hello,

I've been searching the internet for the better part of the day looking for a solution to displaying the speeds of the cars going down the main straight.

Interesting concepts so far are infrared or optic diodes and Arduino but haven't found anything that really jumps out at me. 

Another option is rigging a cheap Radar gun to run "always on" with a large remote LCD screen. I think it's not going to be able to handle 2 or more cars close together. Plus positioning is going to be difficult to maximize accuracy.

Is there any way to utilize the AMB/MyLaps software to measure the transponder travel time? I'd assume you would need another check point to measure against. Seems a pity to not take advantage of the already employed technology of the transponder RF to take measurements of.


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## ta_man (Apr 10, 2005)

On various occasions I have used a programmable bullet chronograph to measure the speed of my RC cars, but that was one at a time. Also, the unit I use has a very small display. There are chronographs out there with big displays but I don't know to what extent they are programmable. Also, the ones I remember with the big displays were not modular so the unit could be reconfigured to measure RC car speed. Since chronographs measure speed by noticing when the object breaks a start beam and an end beam, you would get incorrect readings if two cars crossed the beams close together. Not to mention that most units only show one reading at a time.

My chronograph is almost 15 years old and it is quite possible new ones have computer interfaces such that the computer could display the readings on some kind of scrolling LCD screen.


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