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Motors, controls, and an IR question for micromouse

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  • Ben Estroff
    Hello, again. I ve done what I can to figure things out with my team, but I ve reached a point where I m a bit too outside my knowledge to provide sufficient
    Message 1 of 41 , Mar 8, 2007
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      Hello, again.

      I've done what I can to figure things out with my team, but I've
      reached a point where I'm a bit too outside my knowledge to provide
      sufficient answers. The design has reached a point where we need to
      start testing and characterizing the components, and I'm at a loss for
      how to do so safely.

      Motors:
      We have acquired a pair of RC car motors, INSANE 370 MLST. I can't
      find any information on their current requirements/tolerances, just a
      suggestion that they not exceed 7.2 V driving voltage.

      What would be a good way to determine their limits without damaging them?

      Batteries:

      The batteries we plan to use are 6V Ni-MH rechargables rated for
      600mAh(150) and I'm not entirely sure about what that means as far as
      maximum sourcable current goes. For powering the motors, I've gotten a
      MC78XX 5v Voltage regulator (1 Amp max), and will be using some caps
      to limit the noise, as well as having a common ground but seperate
      v-regs for the controls and the motor circuitry. Since the batteries
      shouldn't supply 1 A at any point, I think this regulator should be
      sufficient, but I'd like to know if I'm making an error in judgement.


      Motor controls:
      We are going to use the PIC18F4431 as our controller, which is
      designed for PWM. I don't think it will be able to adequately source
      the current we'll need, so I'm looking for H-bridge ICs for the
      Motors. Would TI's SN754410 controller suit our needs?

      IR:
      Is the 38 kHz receiver module that Radioshack sells a good choice for
      a distance sensor, or are there other modules that would be better
      suited to that task?


      Thanks in advance,
      Ben Estroff
    • Peter Harrison
      ... My apologies - I rather thought you had dropped a zero. have you looked here: http://micromouse.cannock.ac.uk/motors/index.htm
      Message 41 of 41 , Mar 13, 2007
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        Ben Estroff wrote:
        > We are, of course, going to use gearings that will make our 35-36
        > mm diameter wheels rotate at an appropriate rate.

        My apologies - I rather thought you had dropped a zero.

        have you looked here:
        <shameless self promotion>
        http://micromouse.cannock.ac.uk/motors/index.htm
        </shameless self promotion>

        Pete

        >
        > On 13 Mar 2007 12:43:27 -0700, Peter Harrison <peter.harrison@...>
        > wrote:
        >> Ben Estroff wrote:
        >>> I believe we'll be using three Sharp GPD120 IR range sensors.
        >>>
        >>> And, are these motor specs acceptable? We're hoping to have a maximum
        >>> velocity of 1.6 m/sec.
        >>> **
        >>> *MO-201 GEARBOX WITH MOTOR REVERSIBLE 12V 70RPM *
        >>> Torque 2.1kg/cm
        >>> Rated Voltage 12.0V
        >>> Operating 4.5 - 18V max
        >>> Current - No load 30mA
        >>> Current - Full load 390mA
        >>> Gear Ratio 82:1
        >>> Shaft Speed 70RPM
        >>>
        >>> I'm not sure of the dimensions, but this gearhead motor should fit
        >> inside
        >>> our desired footprint, and be much better in terms of power consumption.
        >>>
        >> I am sure you can do the sums as well as me but...
        >>
        >> To get 1.6m/s with wheels doing 70rpm you will need wheels that are
        >> 436mm diameter.
        >>
        >> Pete Harrison
        >>
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