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[DPRG] FW: Any ideas?

Subject: [DPRG] FW: Any ideas?
From: Kipton Moravec kip at kdream.com
Date: Tue Oct 10 22:20:28 CDT 2000

One mechanical way to modulate the laser signal is to put a spinning wheel
in front of the laser with
holes cut in it.  The laser appears to turn on as it passes a slit, and off
when it hits the wheel.

We had to do this with the Infrared Sensor that is in the new GM cars.

Kip

----- Original Message -----
>From: "gfe" <gfe at coollink.net>
To: "RoboVac" <robovac at mninter.net>; "Robert L. Jordan"
<rljordan at airmail.net>; "Dprglist at Dprg. Org (E-mail)" <dprglist at dprg.org>
Cc: <fhb2000 at pacbell.net>
Sent: Tuesday, October 10, 2000 8:55 PM
Subject: Re: [DPRG] FW: Any ideas?


> I bought a $6.00 laser pointer from Office Depot with the idea of using it
> in a DTMF system, But as WC pointed out no luck getting it to modulate.
But,
> I'm thinking it might make an appearance in Roborama 2001a.
>
> Frank Elia
>
> ----- Original Message -----
> From: "RoboVac" <robovac at mninter.net>
> To: "Robert L. Jordan" <rljordan at airmail.net>; "Dprglist at Dprg. Org
(E-mail)"
> <dprglist at dprg.org>
> Cc: <fhb2000 at pacbell.net>
> Sent: Tuesday, October 10, 2000 9:35 PM
> Subject: Re: [DPRG] FW: Any ideas?
>
>
> >
> > The standard method for increasing the range of photoelectric sensors
for
> > this sort of application is to pulse the beam.  To do this first measure
> the
> > amount of returned light with the light turned off.  Then measure the
> amount
> > of returned light with the light turned on.
> >
> > Subtracting the two values removes the effects of room lights, sun
shine,
> > etc.  Because of the removal of the noise from any external lights the
> > signal to noise ratio is higher and the sensor works at longer
distances.
> >
> > The same technique can be used for a laser sensor also.  However not all
> > laser can be pulsed in this manner.  Most of the lasers used in laser
> > pointers need to be left on for longer then the standard 40kHz or they
do
> > not emit any light.
> >
> > William Crolley
> >
> > ----- Original Message -----
> > From: Robert L. Jordan <rljordan at airmail.net>
> > To: Dprglist at Dprg. Org (E-mail) <dprglist at dprg.org>
> > Cc: <fhb2000 at pacbell.net>
> > Sent: Sunday, October 08, 2000 10:08 PM
> > Subject: [DPRG] FW: Any ideas?
> >
> >
> > > Here is a good question I received. Any ideas for Hank? Sounds like he
> is
> > asking how to get more detection distance from a laser and detector at
810
> > nm. My thought is to use a lens in front of the detector to focus at a
> > distance.
> > > Any other suggestions or ides? Just copy the list and Hank.
> > >
> > > Thanks
> > > Robert L. Jordan
> > >
> > > -----Original Message-----
> > > From: Hank [SMTP:fhb2000 at pacbell.net]
> > > Sent: Sunday, October 08, 2000 3:22 PM
> > > To: rljordan at airmail.net
> > > Subject: Any ideas?
> > >
> > > Do you or someone you know have any optoelectronics ideas?  It's a a
> > silicon detector problem.  I'm utilizing the BS2SX and a 5mw laser diode
> > module @ 810nm and a silicon detector with a 810nm narrow bandwidth
filter
> > to measure when this IR laser pointer strikes black or white.  Laser and
> > detector are side by side and measure light reflected back.  I know it's
> > possible or those long range bar code scanners wouldn't work.  Only need
> > object detection not bar codes.
> > > I can only detect out 2-3ft, but need 8ft range.  I don't understand
the
> > > capacitance or resistance to make detector more sensitive.
> > > I think my op amp is maxing out too.
> > > Thanks - hope you can help,
> > > Hank Burbeck
> > >
> > >
> > > _______________________________________________
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> > > DPRGlist at dprg.org
> > > http://nimon.ncc.com/mailman/listinfo/dprglist
> > >
> >
> >
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> >
>
>
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