27929RES: [SeattleRobotics] Re: Sensing Lasers..
- Jun 2, 2006
>The application actually requires sensing the laser from about 1 m and thatI'm not sure I understand this, but do you mean 1m is too much for IR? I
>is the reason behind using a laser instead of ir led.
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
> 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.
Visit the SRS Website at http://www.seattlerobotics.org Yahoo! Groups Links
- << Previous post in topic Next post in topic >>