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Agreed, those are infrared sensors. This pic is pretty clear:
<a class="moz-txt-link-freetext"
href="http://www.k2.t.u-tokyo.ac.jp/perception/HapticRadar/IMG_1452s.jpg">http://www.k2.t.u-tokyo.ac.jp/perception/HapticRadar/IMG_1452s.jpg</a><br>
<br>
This is a Sharp infrared sensor:<br>
<a class="moz-txt-link-freetext" href="http://www.societyofrobots.com/sensors_sharpirrange.shtml">http://www.societyofrobots.com/sensors_sharpirrange.shtml</a><br>
<a class="moz-txt-link-freetext" href="http://www.acroname.com/robotics/info/articles/sharp/sharp.html">http://www.acroname.com/robotics/info/articles/sharp/sharp.html</a><br>
<br>
Given the narrow beamspread of infrared distance sensors, I would think
ultrasound would work better in the same application. The wider
beamspread of ultrasound should mean fewer transmitters & receivers
to fully cover 360 degrees: probably just four pairs would be fine with
ultrasound. The ultrasound transmitters I've been working with have a
90 degree, -6dB beamspread. Infrared is basically blind outside about
a 25 degree angle.<br>
<br>
Ultrasound tx & rx would pick up bounces off the
huge targets they use in the video, no problem. Driving an ultrasound
transmitter also takes much less power
then infrared, but of course both would be dwarfed by the power of
running a pager motor.<br>
<br>
Tom<br>
<br>
On 3/31/2010 9:04 PM, Adam Skory wrote:
<blockquote
cite="mid:s2m2ec3b38e1003312104y2dca26e4h8a449b08938a0541@mail.gmail.com"
type="cite">
<div class="gmail_quote">On Wed, Mar 31, 2010 at 6:32 PM, Nick
Burrows <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:shamrockman@shamrockman.net">shamrockman@shamrockman.net</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><br>
<div>If they were ultrasonic, they would be stepping on each other,
and echos and other artifacts are more prevalent. Also ultrasonic
equipment tends to be bulkier than equivalent IR gear.<br>
<div>
<div><br>
<br>
</div>
</div>
</div>
</blockquote>
<div><br>
I agree that they look like the IR sensors I've messed with, and
nothing like the ultrasound ones. Although I will say that there are
plenty of ultrasound sensors about that size or smaller.<br>
<br>
Also, there are ways to overcome the ultrasonic sensors interfering
with each other by using fancy timing routines. Our brains' sampling
rate, and not to mention the speed of motors to spin up and down, is
much slower than the time needed for several pulse-echo sequences, so
you really only need to run one sensor at a time. This does NOT
however, help the problems with their super crappy range :( ... and
you're right that there are probably lots of other artifacts to worry
about.<br>
<br>
-Skory<br>
</div>
</div>
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