Subject:
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Re: Ultrasonic Radar
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Newsgroups:
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lugnet.robotics
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Date:
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Wed, 11 Nov 1998 17:45:13 GMT
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Original-From:
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Scott Furman <(fur@)ihatespam(netscape.com)>
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Viewed:
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2865 times
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Ben Houghton wrote:
> What was interesting was a pair of
> what appered to be ultrasonic Xmit/Receivers mounted on either side. They
> look like they might be standard units. Has anyone else seen the article, or
> maybe designed an interface for such a beasty that can be connected to the
> RCX?
Polaroid manufactures the 6500 series ultrasonic ranging system that can be
purchased in single quantities for less than $50 US, but it can't be directly
connected to the RCX. (See http://www.wirz.com for ordering. See
ftp://wirz.com/Polaroid_Sonar/6500.PDF for a data sheet.)
I'm currently looking at interfacing to one of these beasties. It has a trivial
digital interface and it could probably be mated to the RCX with virtually no
glue circuitry *if* I had straight access to a few unused H8 I/O pins and added
a small amount of additional code to the firmware. However, I would prefer a
solution that allowed use of the existing firmware and connectors.
Unfortunately, the RCX firmware does not have sufficient temporal resolution to
use the 6500's digital interface, i.e. a one-millisecond error in measuring
pulse width would correspond to a 1-foot ranging error. So, I'm imagining using
an integrator to convert the pulse width into an analog voltage and then feeding
that through an analog S&H to provide a clean signal for the RCX's A/D inputs.
Another problem will be the current consumption of the device, which may require
an external power supply. The ultrasonic transducer draws 2 amps when it
transmits its tone burst and the amplifier electronics requires 100mA while
idle. Running off the RCX power will require a honking large capacitor and
additional control logic so that the ranging system can be powered down most of
the time.
If anyone else is working on something like this, let me know.
-Scott
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Message has 1 Reply:
 | | Re: Ultrasonic Radar
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| I'm interested in the message you posted to the LUG news server about interfacing an ultrasonic range finder to the RCX. I have a project in mind that could use this, but I lack the time and skills to develop it myself. If you ever get one working, (...) (26 years ago, 4-Feb-99, to lugnet.robotics)
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Message is in Reply To:
| | Ultrasonic Radar
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| I just read an article in Computing (a UK publication) about Prof Warwick of Reading Uni. He is professor of cybernetics, and in the article there was a photo of a machine built using a RCX. What was interesting was a pair of what appered to be (...) (26 years ago, 10-Nov-98, to lugnet.robotics)
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