Line Sensor Height

[KevinSears]

Anyone know how high we should put the line sensor away from the ground?

[Al Skierkiewicz]

Sorry to answer this way, but high enough to be effective and low enough to be accurate. Your mileage may vary...
FLL has been using line following forever. Some of them are good, some are bad, sometimes ambient lighting interferes.

[DarrinMunter]

Ambient light should not be a problem with these because there infared and have a small beam spread at a close range. - These are nothing like the Lego light sensors - those will detect any type of light. These Allen-Bradley units are industrail photo-eyes and are made to be used in a factory environment, and are unaffected by normal lighting.
Also each photo eye has a range adjustment on the top. For what were using them for you many want to have them turned all the way down.
The data sheet that came with these has a lot of good information in the graph tables about the beam spread and distance.

We are now testing our's with our Lunacy bot, we just made a flat plate with the sensor mounted to it and then attached the plate to the bot's trailer hitch.

[Al Skierkiewicz]

Darrin,
I mention it as the studio type lighting used in many regionals has a fair amount of Infrared output.

[wilsonmw04]

slightly different question: How far apart should the be? We are going to prototype with plywood tonight with various distances: 1", 2" and 3" between each eye. What should we expect?

[Jogo]

There are some tips in the line tracking tutorial here: http://decibel.ni.com/content/docs/DOC-8923.

[KevinSears]

http://decibel.ni.com/content/docs/DOC-14730

Reading through this I found to start around two inches and tweak it from there.

[wilsonmw04]

thanks for the white paper. Great place to start. We got our bot tracking a line in a few minutes. It's not competition ready yet, but it's a great place to start!