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Laser distance measurement — Parallax Forums

Laser distance measurement

Ken GraceyKen Gracey Posts: 7,400
edited 2005-01-30 17:25 in BASIC Stamp
Hello:

Has anybody utilized a laser for distance measurement? If so, could you provide some details about the part you used, supplier and BASIC Stamp interface? I've done some searching on Google this afternoon and find mostly pre-packaged industrial sensors (at a cost, usually over a hundred bucks) and I'm wondering if this technology is more accessible to us.

Thanks,

Ken Gracey

Comments

  • JonbJonb Posts: 146
    edited 2005-01-26 23:42
    Hi Ken,
    There is a discussion regarding this here : http://forums.parallax.com/showthread.php?p=523782

    Would be great if you could join in! Even better if Parallax could source something. They are out there, somewhere, waiting for you to grab a few thousand. As you I have only located products using this technology.

    China seems to be the new frontier for this technology... I need to work on my chinese dialects·smile.gif

    Jon

    Post Edited (Jonb) : 1/27/2005 12:01:28 AM GMT
  • kelvin jameskelvin james Posts: 531
    edited 2005-01-29 07:07
    Hi Ken I don't have anything to offer as far as any results of doing this, but i can tell you of my experience of trying to make an idea into reality. Over a year ago i thought of being able to use laser distance technology to implement into the project i am working on. I have googled the net to death and back, periodically over that course of time, and still keep coming up with the same results---zero.
    This seems to be a "protected" technology, as far as the availability of finding an interface. The major consumer players are companies like leica-disto for the handhelds and SICK for the scanners, that offer reliable long distance accuracy. I also looked at some technical theory of these with the idea of possibly making my own and it ain't gonna happen. The mathematics involved is staggering to look at and now i know why these things are expensive and not readily available to anyone. Because i don't give in easily, i will probably go ahead and get one of the less expensive disto models, and see what i can accomplish with it and hopefully not toast it in the process. If anything i will wind up with a really cool tape measure. I personally really hope parallax pursues this, and is able to bring the technology to us at a reasonable cost.
    kelvin
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2005-01-30 15:56
    Recently I purchased a couple of small battery powered laser pointers for about $3 each (there is a big box of them at the store I visited).· It looks like clearance time for them.

    From what I understand these laser pointers cannot operate continuously or they just burn up, but what I was thinking is that I could provide a PWM input to power them in bursts.· They take 4.5volts and one can easily modify the on/off·and mount them.· And they are tiny.

    Having said that - it seems that·they may be the lowest priced source of lasers for distance measurement.· I have fooled around with one outside in daylight and can easily see a red dot at 50 feet.··Obviously, you could use a photo transistor to capture the light pulse.· The rest is really number crunching and testing for feasiblity of distance measurement.

    My original intent was to get these lasers pointing at a 'wobbly' spining mirror for some special effects and use a Basic Stamp to control the mirror movement via servos, but I would be just as interested to see if I could measure distances just beyond the reach of sonar and IR.· Lets say, 10 to 50 feet.

    But, I do imagine that the farther away and the more set up a reflector is, the easier it is to measure a distance.· Maybe because these lasers are red, you could set up a scheme·to use·to the typical 38,500Hz IR sensor (or a notch filtered photo transistor) to selectively read a reflection of a modulated beam.·

    I know, its a lot of maybe and trial and error.· But, it may be worthwhile.· I would love to have my Toddler be able to navigate any indoor space.·

    My only concern is that even these low power devices are labled as a danger to eyes.·

    Of course, if you wanted to do some damage you could send your robot down a rat hole and create a better mouse trap.

    "Three blind mice, three blind mice, three.· . . .'·

    How's that for stupid endings?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    G. Herzog in Taiwan
  • aridaiosaridaios Posts: 57
    edited 2005-01-30 17:25
    One of my applications is·height adjustment·of equipment, relative to·the plan of a·rotating laser beam.
    I am still in searching mode for this project·since I have received no help from anyone.
    So,yesterday, I was·searching for infos on·PSDs (Position Sensitive Detector).
    I found a Laser Target Finder Sensor that uses a small battery powered laser pointer and a
    Hamamatsu S6986 sensor.

    Maybe it is something interesting to you..
    Here is the link:
    http://www.philohome.com/sensors/lasersensor.htm

    Michael
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