Re: TI-H: IR Avoidance (OT)

To: <ti-hardware@lists.ticalc.org>
Subject: Re: TI-H: IR Avoidance (OT)
From: "David Knaack" <dknaack@geocities.com>
Date: Sun, 7 Feb 1999 00:39:50 -0600
Delivered-To: ti-hardware-outgoing@towerguard.unix.edu.sollentuna.se
Delivered-To: ti-hardware@lists.ticalc.org
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From: LuCiDPRoG@aol.com <LuCiDPRoG@aol.com>
>Anyway, how can you set up an IR obstacle avoidance loop with two motors?
<big snip>

Well, here's my idea, take it or leave it.

Set your IR source to direct a fairly narrow beam forward.  Set a single
IR detector with a narrow field of view a few inches away from the IR
source,
pointing at a point on the beam created by the IR source.  This point should
be the distance at which you want the device to start turning.  With no
object in
range the detector should read very little IR.  When an object does come
into
range it will reflect IR back to the detector, signaling the device to begin
turning.
Note that if the beam is very narrow the depth of the detection field may be
too
shallow.

Detection of the intensity of the beam could be done in lots of ways.  I'd
be
inclined to try a phototransistor feeding into a comparitor, perhaps with an
amplifier stage between.  You could adjust the input on the comparitor to
tweak the operation of the circuit.

DK