How to setup a proper speed trap on water?

[Speed3]

I have seen the rc car guys set up timing light for the 132 feet drag.

They would have something that operates by lazer technology.

At the start they have a device on the outside of the 2 cars and then in the middle of the 2 cars is another device that links with the 2 devices on the outside.

So ever thing is lined up parallel to each other.

At the end of the 132 feet have something simular.

So the 2 opponents would position they cars to the devices at the start. Once the cars reach the lazer light the center device activates some lights simular to what you would see on a drag track.

When the light goes green the guys drag to the end.

And the devices records the time it took for them to reach the end.

So you have a device on the outside of the cars and one on the inside.

My question is can something like this be done for the rc boats.

I am think for like the saw event.

You have a device on the outside of the boat and one on the opposite side for start and finish.

And it records how fast the boats cross the outer and inner device at the start and the finish.

[vvviivvv]

i believe that's exactly how its done...

Munich saw was this past week, one of the worlds fastest boats unfortunately disintegrated

In the UK they are using manual stop watches for the official records.... i asked to upgrade the gear but we don't have the scene.

[NativePaul]

I would like to know too, it is not that we don't have the will in the UK, but we don't have the knowledge to do it ourselves.
We did have a member back in the early 2000s that made a set of traps, but while it worked fine testing on road he was never able to get them to work reliably on the water with reflected light and such to deal with. I seem to recall hearing that the water speed traps in use are using a pulsed light at a specific frequency which somehow allows for some kind of interference rejection.

I think that if there was a proven solution for sale the MPBA could be persuaded to invest in it, but I suspect that the systems are created as 1 offs by passionate and talented electronic engineers that are also RC boat hobbyists in their local countries and aren't selling them. Until we get an individual like that in the UK we will have to make do with 2x people at each end of the course with linked stopwatches to a central control box and a person overseeing that box to reject any runs where the 2x times are not within a percentage of eachother. It obviously isn't as accurate as light traps, but it is pretty darned consistent.

[vvviivvv]

I wonder if this has something to do with it...

Or this is just some type of weird flood light

https://photos.google.com/u/1/share/...1wSGJCMGlMZktB

[RaceMechaniX]

Most sanctioned time trials and SAW events for NAMBA and IMPBA here in the US require a surveyed course. That includes knowing the precise position of the center of the turns and the four posts in the banks. I believe the standard distance between lights for both organizations is 330' (1/16" of a mile). Both IMPBA and NAMBA use a "safety curtain" type light sensor often found in industrial settings to shut down machines in case an operator "breaks the beam". Amazingly these light and detector units can work over great distances from one edge of a lake to another. In some lakes this could be up to a 1/4mile. Often the "emitter" lights are placed on the far side of the lake and powered by large batteries to last for an entire day of events. The detectors are placed on the drivers side of the lake and connected wire long wires to a central timing box which converts the inputs into times. The further step is converting the times into speeds for SAW which can take place in the timing box or on a laptop. The current system used by the racers in Germany is a laser system built by Joerg of Team JAG. Instead of light sensors it uses laser beams, but the general setup is the same. Both systems are sensitive to light, fog and water levels. It's not uncommon to have to adjust the lights during the day to accommodate changes. Levels and bubble indicators are often used for course tuning of the alignment between the sender and receiver pair and fine tuning is often done my measuring the output voltage or looking for the reception strength indicated by a series of lights.

It's not too complicated to setup the setup for an experienced do it yourselfer, but getting a reliable system in all weather conditions is tough.

-Tyler

[Peter A]

We use a laser timing system that was brought from the US, sorry I don't know who from. Our course has been measured and surveyed with waratah posts driven into the banks to line up the marks. We do two lap and can do 100M speed runs but it is a bit restrictive due to the pond size, so our club 100M records are only one way.