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1021Re: [ScorbotUserGroup] Re: Arduino Control of Scorbot

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  • Walker Archer
    Jan 4, 2014
      I see what you're saying now.  I very much underestimated the number of ports I'm going to need.  The L298N board needs one PWM port for the enable pin and two digital ports for the input pins.  So 3 ports per motor... a total of 15 ports just for the motors.  That almost leaves nothing left to read the limit switches and encoders.  I'll have to build this with a Mega.
      From: KM6VV <KM6VV@...>
      To: ScorbotUserGroup@yahoogroups.com
      Sent: Thursday, January 2, 2014 5:47 PM
      Subject: Re: [ScorbotUserGroup] Re: Arduino Control of Scorbot
      You can use Pololulu PWM bridges to drive each motor, or a shield.
      Maybe get two motors per UNO? There are two interrupt lines, you might
      be able to get by with a single interrupt line per encoder. Add a
      little logic to "OR" the lines and get an edge, and read two bits from
      each encoder. Motor controller board takes a few lines.

      Alan KM6VV

      On 1/2/2014 2:21 PM, Walker Archer wrote:
      > Multiple UNO's might very well be an option. I wouldn't be at all
      > suprised to find some reason that I can't use all of the ports on the
      > UNO... although I can't think of any right now.
      > *From:* KM6VV <KM6VV@...>
      > *To:* ScorbotUserGroup@yahoogroups.com
      > *Sent:* Thursday, January 2, 2014 5:12 PM
      > *Subject:* Re: [ScorbotUserGroup] Re: Arduino Control of Scorbot
      > I'd consider multiple UNO boards, or a Mega.
      > Alan KM6VV
      > On 1/2/2014 1:50 PM, Walker Archer wrote:
      > >
      > >
      > > Looks kind of pricey. The controllers I see on Pololu only handle two
      > > motors at a time... and the 5amp model goes for $70. For that kind of
      > > money I'd rather try to process the encoders using the Arduino
      > > processor. Granted there is a chance that I might find that encoder
      > > events get lost once the UNO is fully processing all of the inputs. I
      > > might have to opt for a Mega, or Due to get enough processing power. Or
      > > maybe I will have to find a chip that can give me interrupt capability
      > > on those digital signals.
      > >
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