Subject:
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Re: Help!! Polaroid problem!!!
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Wed, 22 Apr 1998 13:18:00 GMT
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Original-From:
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Darkman <LROSKA@CYBERUS.antispamCA>
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Viewed:
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673 times
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The reason you don't need a pull up resistor for the Handy Board is because
the Handy Board has built in 47k pull up resistors on the digital inputs!
-----Original Message-----
From: MAR ERICSON <mar@cooper.edu>
To: Darkman <lroska@cyberus.ca>
Cc: crm0922@bu.edu <crm0922@bu.edu>; handyboard@media.mit.edu
<handyboard@media.mit.edu>
Date: Tuesday, April 21, 1998 10:09 PM
Subject: Re: Help!! Polaroid problem!!!
> Why does it seem like everyone except me needs a pullup resistor and
> perhaps a capacitor somewhere to operate the Polaroid? I've never had any
> problems without any of these components. ???
>
> The first time I connected the sensor, it worked perfectly.
> Maybe I my Handy Board happens to have better components? :-/
>
> -----------
> ericson mar
> Master of Engineering Candidate
> Project: Mobile Robotics
> mar@cooper.edu
> (212)353-4356
>
> Department of Mechanical Engineering
> The Cooper Union for the Advancement of Science and Art
> -------------------------------------------------------
>
> On Tue, 21 Apr 1998, Darkman wrote:
>
> > Are you using a pullup resistor on the ECHO pin? If not that is your
> > problem.
> > The ECHO output is an open collector driver which requires an 4.7 K • pull-up
> > resistor between the output and Vcc.
> > The pull-up is necessary for connecting the module to a digital input.
> >
> > I power mine with a 7805 voltage regulator and it seems to work fine but • i'm
> > not using it continiously.
> >
> > The clicking sound is normal.
> >
> > Another thing I noticed that if I ground the transducer it malfunctions.
> >
> > I hope that helps , Let me know!
> >
> >
> > -----Original Message-----
> > From: Chris Moylan <crm0922@rocketmail.com>
> > To: handyboard@media.mit.edu <handyboard@media.mit.edu>
> > Date: Tuesday, April 21, 1998 10:46 AM
> > Subject: Help!! Polaroid problem!!!
> >
> >
> > > I am trying to use one of the Polaroid 6500 kits from Wirz with my
> > > senior design project. It doesn't exactly use a handyboard, but our
> > > microcontroller is virtually identical at the lowest level. The problem
> > > is when we attach the device to the scope, we NEVER see any significant
> > > voltage on the ECHO pin. With the INIT pulsing 5V every second, we
> > > still get nothing but residual noise (kind of a lot, but at no more
> > > than .5V)and the remnants of the sixteen pulses from the ping. I hear
> > > a clicking sound too, which was unexpected and is quite annoying. Is
> > > this normal? How come I never have any voltage on ECHO? I am not
> > > using the blanking inhibit at all, and if I look at the noise at about
> > > a 200mv setting on the scope, I can see a shape in the noise that
> > > changes with an objects proximity to the transducer, but it is not
> > > anything like a logic level. I have tried a million different ways of
> > > hooking this thing up and have tried two different driver boards. I
> > > am going to buy another transducer tommorrow, but this is getting
> > > ridiculous. How does one go about testing the device? I am powering
> > > it with a HP E3631A Triple output DC power supply with the current
> > > limiter maxed at 5.0 Amps, which should be enough to cover the 2A
> > > pinging surge. Please help me figure out what is going on or a better
> > > way to test it. We connected it to the microcontroller as it connects
> > > to the handyboard, but that of course didn't work either. If you can
> > > respond via email, that would be best because I don't get this list
> > > regularly. Please respond soon so I don't fail senior design!! ;-)
> > > Take it easy,
> > >
> > > Chris
> >
> >
> >
>
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Message has 1 Reply:
 | | Re: Help!! Polaroid problem!!!
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| oh yeah? Well, what about the capcitor, huh? ;) ---...--- ericson mar Master of Engineering Candidate Project: Mobile Robotics mar@cooper.edu (212)353-4356 Department of Mechanical Engineering The Cooper Union for the Advancement of Science and Art (...) (27 years ago, 22-Apr-98, to lugnet.robotics.handyboard)
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