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From: seeker@indirect.com (Stan Eker)
Subject: Re: Need help with LEGO Robots...
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Date: Wed, 19 Apr 1995 04:22:33 GMT
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Michael Caruso (mcaruso@ios.com) wrote:
:  Can someone please give me a step by step process on how to hook up and 
: use the infrared beacon and the GPU infrared sensor.  I'm using the 6.270 
: board version 2.21.  I would really appreciate an example of how to use 
: IR.  I think I can figure the rest out after one example.  Some example C 
: code would be nice too.
: 		thanks in advance
: 			Mike

The pin nearest the edge of the case is ground, the next one in is +5V, and
the innermost one is the signal output.  I *think* the Sharp unit is open-
collector output, meaning it needs a 10K-20K resistor from the output pin to
the +5V line to work with the 'HC11 port structure.

As far as examples go, the port pin that you wire it to will go low when the
sensor is pointed at the IR beacon of another robot.  In a normal home
environment, it will also likely false-trigger due to reflections from white
walls and such.  If the port pin is low, it's seeing 40KHz modulated IR from
somewhere.

For reference, there's a good set of pictures on cher.media.mit.edu in the
postscript file (either /pub/miniboard/docs/sensors.ps or
/pub/fredm/sb-manual.ps.Z, I can't remember which) that shows *exactly*
which pins of assorted thingies do what.  The one I'm looking at with the
Sharp sensor is page 48, section 1.9.6 (top says CHAPTER 1: ASSEMBLY MANUAL).
If you don't have a set of data books handy, it's a good thing to have.

