Infrared and the BS2
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Posts: 46,084
A while back I tried the weekend project on Infrared. I would like
to pass an IR beam through a solution and read the IR signal with one
of the BS2 pins and of course also to the debug screen. I know the
science involved in Infrared Absorbion but I am not an expert in
electronics. Any thoughts?
Thanks,
Curtis Desselles
to pass an IR beam through a solution and read the IR signal with one
of the BS2 pins and of course also to the debug screen. I know the
science involved in Infrared Absorbion but I am not an expert in
electronics. Any thoughts?
Thanks,
Curtis Desselles
Comments
If you transmit an IR beam to an IR detector, the detector receives it or it
doesn't. In other words, it is an on-off situation. You cannot measure the
"amount" of IR transmitted through a medium using the Stamp and a detector.
There probably other more sophisticated methods but using the Stamp is not
one of them. If you wanted to place your detector close to your liquid
medium, then move it away until you lose the IR signal you could probably
correlate distance to opacity or oabsorption, but that is a tough way to go.
Sid
It may be possible to use measure the IR opacity of a liquid by giving
different strengths of IR light, and measuring the outcome.
I believe that the IR detector is going to be pretty much either on or
off, but you might have some success by varying the emitter output.
The Basic Stamp has a pmw method to output a stream of pulses at a
given duty signal. Use a smoothing capacitor (BS1 ap-note 15), and this
will give you a voltage between 0 and ~4.5v. Hook up the emitter to
this, and you might be able to find the point at which the detector
triggers.
The measurements will be relative, but it may be possible to calibrate
it. What's you're application?
Hope this helps,
Paul Jordan
Original Message
From: cenlasoft [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=DWUXiEHpGQfZ2xxGmkD8IqjaclMy7J9uRwgnVs3DIcfz-ux9d6QdAvjuT53QYTW1zTNfaRZK1ykmAx0]cenlasoft@y...[/url
Sent: Friday, February 15, 2002 3:52 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Infrared and the BS2
A while back I tried the weekend project on Infrared. I would like
to pass an IR beam through a solution and read the IR signal with one
of the BS2 pins and of course also to the debug screen. I know the
science involved in Infrared Absorbion but I am not an expert in
electronics. Any thoughts?
Thanks,
Curtis Desselles
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projects on the net that show the modification of a Sharp IR detector module
that causes it to output an analog signal -- the idea is distance
measurement. Perhaps this is a solution (no pun intended). The Stamp is
certainly capable of measuring an analog signal.
-- Jon Williams
-- Parallax
In a message dated 2/15/02 5:59:46 PM Central Standard Time, Newzed@a...
writes:
> If you transmit an IR beam to an IR detector, the detector receives it or it
> doesn't. In other words, it is an on-off situation. You cannot measure
> the
> "amount" of IR transmitted through a medium using the Stamp and a detector.
>
> There probably other more sophisticated methods but using the Stamp is not
> one of them. If you wanted to place your detector close to your liquid
> medium, then move it away until you lose the IR signal you could probably
>
[noparse][[/noparse]Non-text portions of this message have been removed]
changing the modulation frequency sent the IR. The modulation frequency
changes the IR diode output strength.
Download the Robotics text from our web site for details.
-- Jon Williams
-- Parallax
In a message dated 2/15/02 7:20:35 PM Central Standard Time,
automations@c... writes:
> Hello Curtis,
> It may be possible to use measure the IR opacity of a liquid by giving
> different strengths of IR light, and measuring the outcome.
> I believe that the IR detector is going to be pretty much either on or
> off, but you might have some success by varying the emitter output.
> The Basic Stamp has a pmw method to output a stream of pulses at a
> given duty signal. Use a smoothing capacitor (BS1 ap-note 15), and this
> will give you a voltage between 0 and ~4.5v. Hook up the emitter to
> this, and you might be able to find the point at which the detector
> triggers.
> The measurements will be relative, but it may be possible to calibrate
>
[noparse][[/noparse]Non-text portions of this message have been removed]
The QRB1134 is a Fairchild part there is a data sheet at
http://www.junun.org/MiniSumoMarkIII/QRB113x.pdf
BTW I'm not saying that this is the sensor to use, Just that if you take a
phototransistor and use it below saturation you should be able to measure
different intensities
In a message dated 2/15/02 6:45:09 PM Pacific Standard Time, LJGeib writes:
>
> I don't agree with your premise that you can't measure the amount of light
> received with an IR photodetector. Just run the output of a Sharp QRB1134
> detector though an atom convertor .....
[noparse][[/noparse]Non-text portions of this message have been removed]