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 Robotics / 21930
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Subject: 
Laser Target Finder sensor
Newsgroups: 
lugnet.announce, lugnet.robotics
Followup-To: 
lugnet.robotics
Date: 
Sun, 4 Jan 2004 20:09:16 GMT
Viewed: 
253 times
  
Hello,

My latest sensor creation is a laser based detector that can find special reflective targets up to 3 meters away.



You will find here photographs, schematics, tips and tricks to build this sensor.

Some characteristics:
  • Homebrew sensor for the RCX, that can detect special reflective targets.
  • Based on a modulated red laser pointer (sold as a toy for a few $), and a light sensitive integrated circuit (Hamamatsu S6986). Few components used.
  • Uses a disposable camera lens to collect reflected light.
  • The target must be covered with retro-reflective tape (usually used for security clothes, motorcycle helmets...).
  • The sensor is NOT sensitive to white surfaces, only well oriented mirrors can fool it.
  • Largely immune to ambient light.
  • Can detect targets several meters away (depends on quality of laser and retro-reflective tape, works best with bicycle cat’s eye)
  • Binary output: 1 if target in ray, 0 otherwise.
  • Do not provide distance information.


As an application job for this sensor, here is the Barrel Collector Robot which spots cylinders covered with reflecting tape and collects them in its basket. Photographs, movies and full building instructions are included. This robot is built from parts included in Robotics Invention System set and Ultimate Builders set.

...Happy New Year !!!

Philo



Message has 2 Replies:
  Re: Laser Target Finder sensor
 
(...) This is a great work !! I like that kind of detector that brings LEGO to upper technology level. And the robot works quite well...well done!! Chris. (21 years ago, 6-Jan-04, to lugnet.robotics, FTX)
  Re: Laser Target Finder sensor
 
(URL) Many people asked me for the hard-to-find Hamamatsu S6986 chip. It is now available from (URL) Mark III Robot Store> Have a look to their (URL) other products> too: they have lots of interesting (non-LEGO) robotics stuff. And no, I have no (...) (20 years ago, 9-Oct-04, to lugnet.robotics, FTX)

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