View Single Post
  #35   Spotlight this post!  
Unread 02-01-2005, 16:26
phrontist's Avatar
phrontist phrontist is offline
Proto-Engineer
AKA: Bjorn Westergard
FRC #1418 (Vae Victus)
Team Role: College Student
 
Join Date: Feb 2004
Rookie Year: 2004
Location: Falls Church, VA
Posts: 828
phrontist has a reputation beyond reputephrontist has a reputation beyond reputephrontist has a reputation beyond reputephrontist has a reputation beyond reputephrontist has a reputation beyond reputephrontist has a reputation beyond reputephrontist has a reputation beyond reputephrontist has a reputation beyond reputephrontist has a reputation beyond reputephrontist has a reputation beyond reputephrontist has a reputation beyond repute
Send a message via AIM to phrontist
Re: Optical Mouse Navigation

Quote:
Originally Posted by Alan Anderson
We used a test jig with adjustable height and a strip of carpet on a moving platform. During one trial, after I adjusted it for the best focus (as determined by the reported image quality from the sensor), the measured travel from one end of the platform's range to the other was on the order of 400 counts. As long as nothing disturbed the height of the mouse it was very repeatable, with the cumulative distance returning to zero over many cycles back and forth. However, raising the mouse by a couple of millimeters decreased the measurement to about 380 counts. Lowering it a similar amount increased it to about 440. That much variation is probably what you'd get just driving across a smooth carpet, and pretty much wipes out any chance of using the system to get an accurate reading of the robot's position on the field.

To improve things much, you'd have to employ three-dimensional imaging. I doubt there are any cheap devices available to do that.
Could an ultrasonic or infrared range sensor be used to read height, and scale input values accoordingly?
__________________

University of Kentucky - Radio Free Lexington

"I would rather have a really big success or a really spectacular crash and failure then live out the warm eventual death of mediocrity" - Dean Kamen