Subject:
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RE: Motors spinning at startup
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Fri, 30 Jun 2000 17:18:54 GMT
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Original-From:
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Cutts, Patrick H <phc2@AVOIDSPAMpge.com>
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Viewed:
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819 times
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I also tried all sorts of capacitors, etc. in an attempt at solving this
problem. While the capacitors helped to minimize the length of time before
the motors calmed down, there was always a short period of motor craziness
that never went away.
I solved it on my handyboard in the following manner:
I cut the trace where we are told to cut it if we decide to put external
motor power to the board, and then I installed a jumper block with jumper
(like from a computer motherboard) across the cut trace. When I want to
power up the handyboard, I remove the jumper, turn on the handyboard, wait a
second for the handyboard to reset, and then supply power to the motors by
installing the jumper.
-p
-----Original Message-----
From: news-gateway@lugnet.com [mailto:news-gateway@lugnet.com]On Behalf
Of M. Belanger
Sent: Friday, June 30, 2000 9:44 AM
To: handyboard@media.mit.edu
Subject: Re: Motors spinning at startup
I have been having the same motors spinning on powerup "problem" with my
Handyboard. I tried various capacitor combinations on my modified servo
motors
to no effect. Fred M. finally provided the answer:
> > there's nothing that can be done about it, sorry. when the board is
> > first turned on, there's a 1/3 sec period when the motor output latch
> > has a random state. then the cpu comes out of reset and clears it.
In short, there is nothing wrong with your board or motors based on the
symptoms
you described. My solution is to just pick up the robot as I turn it on and
expect that the wheels will turn for an instant (this keeps me from dropping
it
when the spinning wheels startle me). The other option is to unplug the
motors
on powerup. I may switch to a single motor plug (with both of my motors on
one
6 place/4 pin connector) to simplify plugging and unplugging the motors.
MLB
In lugnet.robotics.handyboard, <Falinn@Ukmax.com> writes:
> Hi all,
> I have a problem with the motors connected to my handyboard. When I • first
> turn on the HB, the motors will spin randomly. This happens about every 2-3
> times I switch on. I know this problem has come up before on the list, but
> the post I found didn't answer all my questions.
> What type of caps should I use, non-polarised?
> Also what value capacitance should they have? (My motors are 12v [running
> from HB 9.6v] and draw about 100ma each [2 motors])
> The post also mentioned connecting the cap lead that goes to the negative • on
> the motor to the case of the motor, however my robot is differential drive
> so the +ve and -ve of the motor change depending on which way the robots
> going, what should I do?
> Thanks,
> Matt
>
> --------------
> "Sometimes I think that the surest sign that intelligent life exists
> elsewhere in the Universe is that none of it has ever tried to contact
> us.." -Calvin
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