If you are willing to consider ultrasonic radar for your application,
you can get a lower priced solution than laser. A ultrasonic radar can
be purchased for ~ $70 US for first copy and parts list:
http://www.columbia-center.org/fascinating/rad/radar.html
The parts list allows you to build your own copies.
With the lower speed of sound the timing requirements for the short
distances that you are interested are not as tight when using pulsed
wave ranging. For light pulses to have an accuracy of one centimeter
requires the pulses to be 3.336 x 10^-11 Sec apart (0.01m/3.00 x 10^8
m/s). Also, a laser is more costly and less energy efficient.
For laser ranging, continuous wave (AM/FM) or triangulation techniques
are required which are more costly to implement, and thus for which a
significant market does not exist. For laser triangulation a CCD is
required which leads to the removal of the more costly laser for the
short distances you are interested in, and the addition of another low
cost CCD.
With the commodity pricing of CCDs, a lower cost option is a stereo CCD
camera system where the DSP software tries to position the two cameras
on the same point is space using a very small area of the CCDs. Each
CCD is rotated by servo. The servo angles are used to triangulate the
position of the point in space where the CCDs are focused. This is the
same technique that your eyes use to judge distance.
By combining ultrasonic radar and a stereo CCD system a fool-safe
ranging system should be possible at a reasonable cost. The ultrasound
can also be used to autofocus the CCDs.
- Cheers, Kal.
Guilherme Nelson F De Souza wrote:
>
> Hi,
>
> Sorry, this question is not related to real-time, but I was
> wondering if anybody out there knows of manufacturers of laser
> range scanners, specially for mobile robots. Any name, URL, etc.
> is highly appreciated.
>
> Thanks,
>
> gnd
>
>
>
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