|
Posted by crazygrey on April 13, 2007, 5:35 pm
Please log in for more thread options >
> > > Sonar and IR.
>
> > Thanks Joe, are they any particular advantages of using either one
> > over the other?
>
> That's a good question; I'm sure there must be a compare & contrast
> article somewhere, but I don't know of one of the top of my head. So
> I'll wing it based on what I know, and hopefully others will chime in.
>
> IR is nice and simple (I recommend the Sharp GP2Y0A21YK, available from
> Junun.org among elsewhere); it simply gives you an analog signal that
> corresponds to the distance of something in front of the sensor. It's a
> continuous reading, and you can have as many of these on your bot as you
> like, mounted in pretty much any fashion, and they will not interfere.
> (Or at least, I've never heard of such a problem.) They are quite
> reliable and not much affected by ambient light levels, color of the
> objects, etc., though when the robot they're on is in motion, they tend
> to work better mounted vertically than mounted horizontally.
>
> Ultrasonic distance sensors (i.e. sonar) are generally for
> longer-distance sensing. I haven't actually used these yet, but I think
> they tend to work up to 5 meters or so. These have to be "pinged", and
> they can interfere, so if you have multiple such sensors on your bot you
> ping them one at a time in succession. That's no big deal; a bigger
> problem is if you're in a room (or arena) with other bots also using
> sonar, then the bots may pick up each other's pings and get rather
> confused. FIRST LEGO League discourages the use of the ultrasonic range
> sensor for this reason. (Why in the world LEGO doesn't include an IR
> distance sensor in the standard kit, I can't imagine.)
>
> Hope this gets you started -- use your google-fu to find out more; there
> is a lot of information on these sensors out there.
>
> Best,
> - Joe
Thanks for the reply Joe, very helpful information and definitely will
google about it more.
| 
XML site map
> industrially to measure a distance to an object (e.g. another robot)
> to avoid collision for instance?