Subject:
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Re: Mobile Robot Question
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 21 Apr 1999 17:33:06 GMT
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Original-From:
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Curt Mills, WE7U <[hacker@tc.fluke.]StopSpam[com]>
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Viewed:
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963 times
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On Tue, 20 Apr 1999, Andre Philippi wrote:
> I'm building a mobile robot using an R/C car with an Electronic Speed
> Controller (ESC) as the mobile platform, the Handyboard for sensorial data
> aquisition, and servo control; and a Linux "box" for GPS, videoconferencing,
> wireless communications, high level autonomous behavior, and remote control...
>
> My question is...
>
> How much are the GPS, the ultrasound radar, the electronic compass, the
> stepper motor (that holds and rotates a "turret" containing the ultrasound
> transducer, the video camera, some IR sensors, and eventually a Laser
> range-finder), the servo motors (that control the car), the video camera (I'm
> NOT using a wireless video transmitter), the ESC, and the packet modem going
> to cause electromagnetic interference to each other? Should I expect any
> other type of interference ? Which devices are not gonna be affected or cause
> any type of interference ? Which devices generate interference, and what are
> my options accessing the problem ?
>
> Wow! If someone is able to answer all that, we should post the answers in some
> FAQ...:)
Can anyone answer all that? I think the answer is "it depends".
Unfortunately it depends on so many variables that you'll just have to
implement one system at a time, checking each thoroughly and modifying as
you go. Make sure to go back and re-verify each previous system as best
you can each time you implement something new. I suspect it'll be a long
process.
The GPS shouldn't get much interference from anything else unless it gets
something coming in on its power lines. Keep the GPS away from your
motors though. If you use a DGPS receiver (300Khz), expect great amounts
of interference from your other equipment on that radio. Depending on how
the ESC is designed, it may throw out a lot of noise which could affect
your wireless comm link or some of your sensors. Any motors and some
metals can affect your compass. You comm-link could be affected
drastically by all of the other noise sources.
If (when?) you start having troubles, look at power-supply filtering for
each system, and try locating them in different orientations and at
different distances to try to determine which system is affecting which.
GPS is running the 1.5GHz range, Ultrasonics around 40KHz, Comm link ??
(probably low KHz if anything), DGPS around 300KHz, ESC could be in the
KHz range if it is a chopper, Linux box would generate multiple
frequencies, Handyboard 8MHz and many frequencies below, packet modem
(separate unit from comm radio?) could generate lots of frequencies.
Servos, steppers, and motors in the video camera possibly? can generate a
wide range of frequencies.
I had a packet modem (TNC) interfering with the radio it was attached to
at 144.99 MHz at one point. It threw a spur up right on that frequency.
The packet modem had a Z80 processor in it. Gives you a clue as to what
you might expect.
Have I scared you enough yet? ;-)
Good luck. Wish I had the time and money to do that. Sounds like fun.
Curt Mills, WE7U hacker.NO_*SPAM@tc.fluke.com
Senior Methods Engineer/SysAdmin
"Lotto: A tax on people who are bad at math." -- unknown
"Windows: Microsoft's tax on computer illiterates." -- WE7U
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Message has 1 Reply:
 | | handyboard clock speed
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| Ive checked the mailing list archives and i cant find a simple answer to the following question: Is it possible to run the HB at >2Mhz? That is, can I run a different version of the 6811 perhaps and get 8Mhz? What are the advantages/disadvantages? (...) (25 years ago, 22-Apr-99, to lugnet.robotics.handyboard)
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Message is in Reply To:
| | Mobile Robot Question
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| Hi, I'm building a mobile robot using an R/C car with an Electronic Speed Controller (ESC) as the mobile platform, the Handyboard for sensorial data aquisition, and servo control; and a Linux "box" for GPS, videoconferencing, wireless (...) (25 years ago, 20-Apr-99, to lugnet.robotics.handyboard)
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