Measuring vehicle distance

Ashraf HZ

Ashraf HZ

@Ash Oct 21, 2024
Heya!

I'm still in the planning stages of one of my projects, a telemetry system for my car. One of the function's I'd like to implement is a detector to measure distance of the car in front, which I can then calculate relative velocity.

The most practical solution would be using laser as the range finder, using speed of light and time of flight for calculations. However, I'm having difficulty in locating Class 1 laser modules/pointers. Of course, there are cheap laser pointers out there, but since they are mostly Class 2, I'm definitely NOT using those on the road.

I might get a 2nd hand rangefinder used in golf (Bushnell Yardage Pro Sport 450) and hack it. Range of about 200m is quite decent, though I'm quite stumped on how a Class 1 laser can achieve that distance.

Anybody know where I can get a long range Class 1 laser modules? I'd probably need to also mount a scope or monocular to the detector. The assumption of all this is that I'm driving on a straight flat road, ignoring any azimuth or elevated deviations of my target car.

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  • Ashraf HZ

    Ashraf HZ

    @Ash Jul 23, 2013

    Even after 3 years, there is still no viable solution. I'm still quite stumped on getting a cost effective Class 1 laser module. Any CEans can advise on this?

    Hacking the rangefinder is the only bet it seems. However, compared to my first post, I now feel I need to control the azimuth and elevation deviations as well, since I need to reliably track cars. Probably mounting on x-y axis servos and syncing together with a camera can work? Argh, this brings me back to the MATLAB days..
  • Ramani Aswath

    Ramani Aswath

    @ramani-VR4O43 Jul 23, 2013

    ash
    Even after 3 years, there is still no viable solution. I'm still quite stumped on getting a cost effective Class 1 laser module. Any CEans can advise on this?
    Have not done any work on laser range finding. I am sure that you would have considered Laser interferometry.
    Laser modules are available for assembly lines up to 100 m. Have you looked at these? May be expensive.

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  • Ashraf HZ

    Ashraf HZ

    @Ash Jul 25, 2013

    Thanks for the links!

    The flexpoint laser modules come in Class 2 onwards. Not sure if I would risk using that on the road, since I will be aiming them at other cars (with the risk of reflection off the rear view mirror of front cars). Probably can use them for lab testing, but I'll need to stick to Class 1 no matter what if I am to deploy it on public road.
  • Ramani Aswath

    Ramani Aswath

    @ramani-VR4O43 Jul 25, 2013

    I got an impression that flexpoint also had harmless class 1 versions.
  • Ashraf HZ

    Ashraf HZ

    @Ash Jul 25, 2013

    A.V.Ramani
    I got an impression that flexpoint also had harmless class 1 versions.
    I'll just drop them an email then to inquire 😀 thanks