laser rangefinders/scanners for hobbyists?

"Mike Noone"

I've heard of people (sorry, couldn't find the links) trying to use servo
actuated mirrors to transform those rangefinders into scanners. I don't
think it's so easy to do, otherwise SICKs (the coffe makers) would be much
cheaper.

That's what I've thought about doing - but the timing for it would be hard
without having very detailed specs on the rangefinder being used, and I
doubt those specs would be easy to come by.

SICKs are awesome, too bad they're so big. Any idea how much they cost? On
my current project they would be out of the question as they probabaly
weight about as much as my entire robot, if not more.

-Mike

"Mike Noone"

If I'm not mistaken, last time I checked the simplest one was about $500. I
went to the DARPA Grand Challenge, and most (if not all) participants were
using several of them. I believe they had some kind of sponsorship offered
to the teams, I don't know.

Cheers

Padu

"Padu"

I might be terribly wrong. Just found one on ebay for $650-$800

http://cgi.ebay.com/Sick-Optics-Proximity-Laser-Scanner-PLS101-312_W0QQitemZ7606433989QQcategoryZ42899QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

or

http://tinyurl.com/glv53

cheers

Padu

I wish I could afford that right now!

Tim

  > If I'm not mistaken, last time I checked the simplest one was about $500. I

     More like $5000.  And we paid list price.

     There's no fundamental reason they have to cost that much, but
the market is tiny.  They're very well built mechanically; people
have wrecked vehicles and found the SICK LMS units undamaged.
Ours never failed us.

     SICK LMS units have rather outdated electronics, though.  There's only an
8-bit microprocessor inside, trying frantically to keep up with 180 points
per scan with 75 scans per second, plus a 500Kb serial RS-422 link.
It's not quite fast enough, and when you send to it, you have to space
out the bytes with delay time between them.  SICK talked vaguely of an
Ethernet interface, but never delivered one.

                John Nagle
                Team Overbot

Even low powered lasers can have a safety issue and it is the
responsibility
of the operator to not point a laser into someone's eye. If you use a
laser
rangefinder or scanner in a robot how do you ensure that it won't scan
an eye?  Even low power invisible infra-red can be a problem because
the
eye might focus the beam onto the retina and cause damage.

I have always just assumed that this was the reason that laser
rangefinders
are not a cheap popular consumer item.  They could probably be made for
a few bucks in reasonable quantity but then there is the liability
issue.

@g10g2000cwb.googlegroups.com:


Laser rangefinders were widely used in the darpa grand challenge, and I
haven't seen anybody in any of the videos or pictures on with any sort of
special equipment to protect themselves. Thus they must be at least
relatively safe.

-Mike

Blink reflex protects you from class II visible laser IIRC.

Tim

@g10g2000cwb.googlegroups.com:


And yet $3 laser pointers which are nowhere near as useful are universally
available...

Mitch

What kind of scanners are you talking about here ??

Do you have any links ??

thanks

These are some very nice ones:
http://www.sick.de/de/products/categories/safety/espe/laserscanner/en.html

-Mike

You can use a regular laser pointer at an offset to a camera. By
triangulation of the position of the laser dot in the camera picture,
you can find the distance of the point you lit. If you generate a laser
line instead of a dot, you get a line scanner. Move that around with a
servo, and you can scan depth.

Search google for depth, structured light, triangulation, etc.