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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Tue, 21 Apr 1998 15:15:25 GMT
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Original-From:
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Darkman <lroska@cyberus.AVOIDSPAMca>
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Viewed:
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603 times
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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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| 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. (...) (26 years ago, 22-Apr-98, to lugnet.robotics.handyboard)
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