Subject:
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Re: Infrared Optosensors
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Fri, 5 Jun 1998 15:16:07 GMT
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Original-From:
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Randy Sargent <RSARGENT@NEWTONLABS.nomorespamCOM>
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Viewed:
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1210 times
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I've had pretty good luck getting up to around 2" by using a standard IR
LED and standard IR phototransistor, modulating the IR LED in software,
and looking at the analog value returned from the phototransistor like
so:
{
int refl;
led_on(); refl += analog(1); led_off(); refl -= analog(1);
led_on(); refl += analog(1); led_off(); refl -= analog(1);
led_on(); refl += analog(1); led_off(); refl -= analog(1);
printf("Reflectance is %d\n", refl);
}
You want to use a high-powered IR LED and put around 100 ma through it.
-- Randy
Fred G. Martin wrote:
>
> 1/2" is actually pretty good range for a basic reflectance sensor.
> try using them in the analog inputs -- you should get readings that
> let you read out to about 1".
>
> to get better than that, you need a modulated signal, like Pandit has
> described.
>
> Fred
>
> In your message you said:
> > I interfaced 3 infrared optosensors to the digital inputs on the handyboard.
> I'm a little dissapointed in their performance however. The only time they
> give
> a reading of "true" is if they are about a half an inch or closer from the
> tar
> get. Any further away than half an inch results in a "false" reading because
> th
> e sensors are out of range.
> >
> > Is there any way at all to have a bigger range. I want to have the sensors 2
> inches away from what they are to detect. If anyone has been using the
> optosens
> ors I'd like a little input.
> >
> > -Should I use smaller resistors on the sensors?
> >
> > -Is the range short because of how fast the digital(); function checks the
> > se
> nsor? If it took longer to check would it then give the sensor more time to
> let
> the infrared beam to reflect back?
> >
> > -Do I need stronger optosensors all together?
> > ( I'm using the Quality Tech. 1114, as shown in the HB manual )
> >
> > Thanks in advance,
> > _________________________________________________
> > ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
> > Brian Carvalho [ brian-c@ieee.org ]
> > DeVRY Institute
> > New Jersey
> > _________________________________________________
> > ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
--
----------------------------------------------------------------
Randy Sargent Newton Research Labs
President Robotic Systems and Software
rsargent@newtonlabs.com http://www.newtonlabs.com/
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Message is in Reply To:
 | | Re: Infrared Optosensors
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| 1/2" is actually pretty good range for a basic reflectance sensor. try using them in the analog inputs -- you should get readings that let you read out to about 1". to get better than that, you need a modulated signal, like Pandit has described. (...) (26 years ago, 5-Jun-98, to lugnet.robotics.handyboard)
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