Subject:
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Re: Pull Up Resistor
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Thu, 6 Aug 1998 16:34:32 GMT
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Original-From:
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Sheridan Edward Ethier <SEETHIER@stopspammersZEUS.UWATERLOO.CA>
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Viewed:
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1186 times
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I checked the ECHO signal and found it to be at 2.0V when plugged into
TIC3 on the HB. I also applied a pull-up resitor which did send ECHO
to 5V when not pinging. However, in both cases, I still had seemingly
random positive and negative values returned from the sonar.
Any insight would be appreciated.
Thanks,
Sheridan
On Wed, 5 Aug 1998, Rick Moll wrote:
> Sheridan Edward Ethier wrote:
>
> > The polaroid documentation mentions that a 4.7K resistor should be placed
> > between ECHO and Vcc. Should this be done when interfacing to the HB?
>
> The sensor connectors on the HB already have pullup resistors on the signal
> inputs (as I recall they were 47K), so you shouldn't need to add an
> additional pullup. If you want to make sure, just check the signal
> connection with a voltmeter to verify that it's close to 5V when the sonar is
> not being pinged.
>
> Rick
>
>
>
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Message has 1 Reply:
 | | Re: Pull Up Resistor
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| (...) I just checked my copy of the Polaroid Sonar Module documentation, and it does in deed state that the module can sink up to 0.1 mA when ECHO is pulled high. It sounds like your module is drawing around 0.064 mA = ((5V - 2V)/47Kohms), so it is (...) (26 years ago, 6-Aug-98, to lugnet.robotics.handyboard)
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Message is in Reply To:
| | Re: Pull Up Resistor
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| (...) The sensor connectors on the HB already have pullup resistors on the signal inputs (as I recall they were 47K), so you shouldn't need to add an additional pullup. If you want to make sure, just check the signal connection with a voltmeter to (...) (26 years ago, 5-Aug-98, to lugnet.robotics.handyboard)
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