Subject:
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Re: Help
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 25 Nov 1998 15:56:50 GMT
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Original-From:
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SOMEWHERE@UNM.EDUnomorespam
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Viewed:
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2386 times
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Hi John,
It depends on what kind of circuit your infrared sensors are in. An
infrared diode or transistor can not be hooked directly into the HB.
They have to be biased properly and the signal amplified to be
compatible with either the digital or analog inputs.
One way of getting useful information from your pair of sensors is to
bias your raw sensors properly. For small targets at large distances,
find a set of lenses from Edmund Scientific to focus your target image
on the IR sensor. The formulas for computing the focal lengths needed
are in most basic Physics texts. IR will focus like visible light
except the focal length changes by a factor n because of the different
frequency of light. Then find two sets of three tubes (any material
durable enough for the project)that will tightly slide over each other
and are twice the focal length you will be using. Mount the large lense
in the middle of the big tube. The other lense in the end of the second
tube. And the infrared sensor at the end of the smallest tube. A hot
melt glue gun works well.
Make or find two small ferrous (iron based) metal enclosures to mount
the sensors in. Cut a round hole just large enough to allow the focused
diameter of the IR light in. Position the IR sensor at a known distance
from the front of the metal enclosure, but try to make the angle of the
focus less than 45 degrees so that the sensor is mounted a short
distance from the hole. Again hot melt will secure it nicely if the
metal is coarse sand papered first. Mount the IR detector casing in the
center of the end of the smallest tube (i.e. the focus of the lenses).
Use a small length of triaxial cable to interface the IR sensor with
your buffers/amplifiers. Use the triax shield to ground the IR sensor
metal enclosure.
Reasons: The ferrous enclosure is desirable because IR detectors are
sensitive to electric fields and they will give false readings. The
sourse IR intensity drops with the square of the distance. Therefore
lenses increase the range of a sensor significantly and help to
positively identify the position of the target. If a broader field of
view is desired at short ranges, the lenses can be omitted.
To electronically interface the sensors. A single source non-inverting
op-amp can be used to tie directly into the Handy Board. This will
allow a gain adjustment to get whatever deviation you want from the
signal.
And/or feed each sensor into a differential op-amp with offset control
to monitor the difference between the sensors. If you are using two
sensors, I'm guessing this is the signal you want anyway.
Good luck in your experimentation,
James Dunn
John A. Atkinson-Abutridy wrote:
>
> Hi, I need to send and receive IR signal (not from remote controller) in
> the
> Handyboard
> 1.- Could someone tell me what kind of routines I must use???
>
> NOTE: I am not interested in getting codes from a RC, but also signal
> to proccess differents intensities.
>
> 2.- The HB has an own IR receiver, I bought two more IR sensors,
> Must i connect them to the digital port 0,1,2,3 ????
>
> Thank you
> John
>
> --
> John A. Atkinson-Abutridy EMAIL: atkinson@inf.udec.cl
> Profesor Asistente
> Dept. de Ingenieria Informatica URL: http://www.inf.udec.cl/~atkinson
> Universidad de Concepcion
> Concepcion, CHILE
>
> Phone: (56) (41) 204305
> Fax : (56) (41) 221770
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Message is in Reply To:
 | | Help
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| Hi, I need to send and receive IR signal (not from remote controller) in the Handyboard 1.- Could someone tell me what kind of routines I must use??? NOTE: I am not interested in getting codes from a RC, but also signal to proccess differents (...) (26 years ago, 24-Nov-98, to lugnet.robotics.handyboard)
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