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Subject: 
Re: The IR beacon, was Re: Homebrew sensors?
Newsgroups: 
lugnet.robotics
Date: 
Mon, 16 Nov 1998 17:25:16 GMT
Original-From: 
Eric Brandwine <(ericb@)NoSpam(mitre.org)>
Viewed: 
2326 times
  
"ph" == Paul Haas <paulh@hamjudo.com> writes:

ph> I think that the light sensor is read once every 3 milliseconds.  When you
ph> think you're reading the light sensor, you're really getting the last
ph> sample.  Anyone want to verify that?
Dunno about the bit level, but the Official Lego docs that shipped
with it say that sensor watcher stacks for the light sensor get
activated when 2 consecutive readings of the light sensor are on
opposite sides of the threshold value in the sensor watcher.  That
would seem to indicate resonably high freq polling.

ericb


ph> I have to read the light sensor multiple times because sometimes I sample
ph> during a stop bit.  The light is on for zero's, off for ones and stop
ph> bits.  (maybe the parity bit too, not sure).

ph> My robot is the classic 2 motors (1 per wheel), and a bump sensor.  It
ph> works fine running Torbot programs.  I stuck a light sensor on it.

ph> I plan on making a "garage" for the RCX.  An otherwise dark place with the
ph> IR tower.  The RCX will know it is "home" when the IR beacon is very
ph> bright and it is otherwise dark.  I get beacond on readings of 70 to 100
ph> at 6 inches depending on alignment.

ph> --
ph> paulh@hamjudo.com  http://www.hamjudo.com
ph> The April 97 WebSight magazine describes me as "(presumably) normal".



--
Eric Brandwine, Systems Engineer | What is the definition of an engineer?
EricB@Mitre.org                  |   Someone who solves a problem you
MITRE Corporation, McLean VA     |   didn't know you had in a way you
(703) 883-3319 F: (703) 883-1917 |   don't understand.



Message is in Reply To:
  The IR beacon, was Re: Homebrew sensors?
 
(...) The light sensor is directional without a tunnel. I use the IR tower as a beacon. I've got a perl script that listens for RCX messages. Here's the normal sequence of events: 1. RCX sends the message 2 "Turn on your beacon, so I can find you" (...) (26 years ago, 13-Nov-98, to lugnet.robotics)

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