Measuring speed of a passing vehicle

[Dwayne]

Hello Robert,

Robert>>Light beams are the accepted method of timing wheeled vehicles (last one I saw personally was used to time a car at over 760MPH).<<

Humm Robert... this is the speed of sound... It was only broke not too long ago (that I know of ) in the California? desert by a rocket car... But I am not sure about overseas, and their accomplishments... are you sure you are not thinking 760KPH?

Dwayne

[kitcat]

All very interesting.
I think I will be having a few problems with many bikes bunched together and multiple triggers. And then there are the front wheels and the back wheels. I could end up having about "triggers happening at once".
I had originally thought of calculating the average speed of the bikes and triggering it by hand or with one beam nit that is a bit of a cop out. I have already started on the PC end. THe system runs from midi and we treat it like a "visual" musical instrument. For anybody who is interested there is a link here to a very bad mpeg of a brief snippett from our show at Alton Towers. We developed moving platforms for the flames which you can see at the front. To get an idea of scale, our flames are about 24' high and the background is Millenium fireworks + lasers etc.
http://elmtreecottages.co.uk/Alton1.AVI
(I'm afraid it is about 24 meg)

[Melanie]

GPS Receiver modules are small, lightweight and cheap. They will report back the speed at which they are travelling, and you can have an unlimited number racing around the track reporting the stats back to you. The only drawback is the start aquisition time, but once you've locked, theres no problem.

[Luciano]

Hi!

Motorbikes at full throttle position are very loud.

What about a sound detector very close to the race track?

Use a microphone with adjustable gain so it won't be
affected by other noises like your fireworks.
Mount the microphone in a tube, to isolate unwanted noise
and make a directional microphone.

You detect the sound of the passing motorbike and after a fixed delay
you trigger the fireworks. Do that where the motorbikes are
at full throttle so that the covered distance will be always
the same and the noise very loud.

There is no need for speed/time calculation unless you trigger the
firework only for the best speed/ best laps.

Make sure that all the race participants (pilots) are aware of your fireworks
and that the generated light will not temporarily blind them.

Luciano


200 kilometer/hour = 55.5555556 meter/second
200 kilometer/hour = 5,555.5555556 centimeter/second
200 kilometer/hour = 124.2742384 mile/hour (mph)
200 kilometer/hour = 182.2688831 foot/second
200 kilometer/hour = 2,187.2265967 inch/second