Originally Posted by iRocco
A couple of things to consider on this:
1. Are there any FCC issues with using lasers in this way?
2. What is the chance they will set off anyone with a laser detecting fuzz buster?
3. how are you planning on keeping the emitters free from dust & dirt?
4. Would this be easier if you simply used sonar, like a modified fish-finder?
Depends on the class and power of the laser. No FCC issues regarding Lasers that I know of. Nobody uses lasers for communication, at least not commercially (it is possible to transmit sound with pulses of light....I've done it in a lab...not fiber optic, actual exposed beam).
Setting of a Laser detecter would be wholly dependent on the wavelength. I'm not sure what the detectability bandwidth of a typical laser detector is, but it would be easy to work around that.
Keeping the laser aperture clean is simple. You don't expose it unless the system is running. Most lasers in commercial applications are transmitted through an optically coated flat window as a final barrier against the elements. Keep the window clean by wiping it off when you wash the car.
Sonar doesn't work too well without water as a transport medium. Kinda like a fish out of water. You'd have to go radar, and good luck getting a license for that. The potential lawsuits are unimagineable.
It'* far-fetched, but it'* possible, and I think lasers are the best pick for a detection device in the speed/distance category.