Alt-BEAM Archive

Message #13614



To: beam@corp.sgi.com
From: Ken Hill beam@sgiblab.sgi.com
Date: Tue, 18 Apr 2000 00:56:31 -0700
Subject: Repost anyone? Photopopper questions from newbie.


I'm constructed a couple 1381 SEs that are popping nicely.

My problem is combining them into the beam-online circuits "Photopopper"
circuit. I need to use LDRs but can't figure how to substitute them for
the photodiodes exactly (read all the discussion but need pic:).

Also, I'm not sure how the touch sensors work. Do they ground the V+ input
to the 1381 keeping it from firing and letting the other motor turn it away
from the obstacle?

(Photopopper drawing shows the wires crossing near 1381s but not sure if
they are connected at that junction).

And lastly, is the RC timer (if that's what it is?) used to keep the motor
from firing for a while assuring the turn or what?

I can build em, but I want to understand em :) Thanks for any help.

Ken

P.S. It appears that if you are willing to use 2 solar cells (1 for each
SE) that except for touch sensors, they really don't need to be combined
and the cells can replace the photodiodes to change direction since if
mounted angled away from each other they will catch more light on one side
causing one motor to pop more often and turn toward the light. (Obvious you
say - well I said newbie :)


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