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27931Re: Sensing Lasers..

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  • Mustafa
    Jun 3, 2006
    • 0 Attachment
      Sorry to confuse you Pedro. But this is only a prototype of an
      application working on lasers.


      --- In SeattleRobotics@yahoogroups.com, "Pedro Drummond"
      <electronics@...> wrote:
      >
      >
      > >The application actually requires sensing the laser from about 1
      m and that
      > >is the reason behind using a laser instead of ir led.
      >
      > I'm not sure I understand this, but do you mean 1m is too much for
      IR? I
      > have seen homemade IR links (lens-less) up to 10m, and up to 20m
      using
      > lenses. Our TV remote has a better range than 1m.
      >
      >
      >
      >
      >
      > --- In SeattleRobotics@yahoogroups.com, Alan King <alan@> wrote:
      > >
      > > Mustafa wrote:
      > >
      > > >Hi everyone..
      > > >
      > > >I am making a circuit for sensing laser modulated at a
      frequency of
      > > >10kHz. I tried using phototransistors and photodiodes to sense
      the
      > > >laser, but both are unable to give sufficient response for
      laser. the
      > > >photodiode circuit works fine with ired, but does not show any
      change
      > > >in output with laser.. Does anyone know what can be used to
      solve the
      > > >problem? The laser used is a small ordinary one available from
      > > >road-side vendors.
      > > >
      > > >
      > > >
      > >
      > >
      > > Look at the beam angle and sensitivity. Lasers put out very
      little
      > > light except down the beam, unless your spot is right on the
      detector
      > > you won't see much of anything. Get one that has changable
      lenses and
      > > spread it out, or if you need long distances get the spot on the
      > > detector. If you've already got the spot on the detector, you
      may be
      > > just swamping out the detector, with so much light coming in it
      may
      > just
      > > not be turning off at all. If it's working with the relatively
      low
      > > amount from an IR LED it may be way too sensitive for a direct
      laser
      > > beam.. Also, working with IR LED? Cheap red laser pointer? If
      it
      > > has a dark IR filter you may not be getting much of anything to
      the
      > > sensor at all if you're using the same sensor. Of course if
      you've
      > > tried several then most likely at least one or two were clear
      enough.
      > >
      > > Alan
      > >
      >
      >
      >
      >
      >
      >
      >
      > Visit the SRS Website at http://www.seattlerobotics.org Yahoo!
      Groups Links
      >
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