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12535Re: [SeattleRobotics] Re: Power Supply Tricks?

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  • Kipton Moravec
    Jan 1, 2003
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      I have one last thing for you to try. On the power supply to the
      microcontroller put a diode between the battery and the big capacitor on the
      input of that one power supply.

      If the motor is sucking up too much current, the capacitor will hold the
      voltage up for the processor since it will not be able to discharge because
      of the diode. Of course this assumes you have the head room for the .6 V
      diode.

      Finally another kluge you can try. Assuming you have at least 12V for your
      5V regulator, Put a diode between your main batteries and the input
      capacitor for the 5V regulator (as above). In parallel put a 9V transistor
      battery with a diode to the same input capacitor for the 5 V regulator
      capacitor. If the input voltage falls below about 8.4V, the 9V battery
      kicks in for the 50ms or so until the 12V battery recovers.

      Kip

      ----- Original Message -----
      From: <pjc30943@...>
      To: <SeattleRobotics@yahoogroups.com>
      Sent: Tuesday, December 31, 2002 6:42 PM
      Subject: [SeattleRobotics] Re: Power Supply Tricks?


      > Hi Paul,
      >
      > Thanks for the reply.
      > My driver is controlled by a serial stream.
      > Interesting thought about the switch. It led me to think about
      > whether the switch was arcing (significantly) as I closed it, causing
      > all sorts of interference. But I don't think that this is the case,
      > after more examination.
      >
      > But good idea, I'll keep it in mind for the future.
      > Thank you,
      > Paul
      >
      >
      > --- In SeattleRobotics@yahoogroups.com, "Paul Davis" <youhere@h...>
      > wrote:
      > > Do you have the appropriate pull up/down resistors on the control
      > lines to
      > > motor drivers? Maybe while the processors are in reset they are
      > floating or
      > > at the wrong value causing shorts and other whacky stuff, causing
      > the power
      > > to sag in the rest of the robot or at least drain those large caps
      > and
      > > causing the charging problem already mentioned.
      > >
      > > Paul Davis
      > >
      > > >After original powerup, even with motors running, there are no
      > resets.
      > > >Only when they are turned off and on again during operation (i.e.,
      > the
      > > >glitch occurs in the beginning before the micros are fully on, so
      > they
      > > >don't notice).
      > >
      > >
      > >
      > >
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