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Motor speed control with R/C speed controller — Parallax Forums

Motor speed control with R/C speed controller

glasoglaso Posts: 38
edited 2004-10-31 04:27 in BASIC Stamp
Does anybody tried a R/C motor speed control device (like GWS ICS 300) to control motors with a basic stamp?

I trying to find information about the connections, the current draw (if I can use the stamp regulated output as source for the controller), maximum voltage of the motors source, etc.

Comments

  • Vern GranerVern Graner Posts: 337
    edited 2004-10-28 20:31
    Glaso:

    To control a motor from the basic stamp, the simplest method is to use a serial speed controller such as this:

    http://www.parallax.com/detail.asp?product_id=30001

    I looked at the GWS ICS 300 and it appears to take a PWM servo control signal and covert it to PWM DC motor speed control....? I assume to be used to allow you to "throttle" a DC motor in a model plane? The basic stamp can create a PWM signal that is acceptable to servo's so I would assume it would be able to provide a controlling signal to the GWS ICS 300. I don't know if I understand the point of your question though. The Basic Stamp has an on-board 5v regulator, but it produces very little amperage beyond what is required to run the stamp itself. I would certainly NOT use the stamp's on board 5v regulator to provide power for the GWS-ICS-300, as that module seems abole to draw in excess of 8 AMPS.

    Hope this helps.. smile.gif

    Vern
  • allanlane5allanlane5 Posts: 3,815
    edited 2004-10-28 21:20
    Typically you use the BS2 "PULSOUT" command to generate an R/C compatible Servo control signal.
    A normally low, with a 1 to 2 mSec pulse high, repeated every 20 mSec to 50 mSec controls the servo.· 1.5 mSec is the 'center' or 'stopped' position.· Less than 1.5 mSec goes 'backwards'.· More than 1.5 mSec goes 'forwards'.

    The Motor Mind C ($55) accepts two of these signals, and drives two attached brushed DC motors up to 24 volts, up to 4 Amps.

    The GWS ICS 300 ($10) takes one of these signals, and drives an attached brushed DC motor, up to 8 amps, (5 to 8 cells is 4.5 to 12 volts).

    Either one of these seems a nice way to use the BS2 PULSOUT command to drive DC motors.
    Note you *must* have a separate 'motor' drive power supply, as well as a +5 VDC BS2 supply (I suppose you could use a regulator on the 'motor' supply to get the BS2 supply. Use a big capacitor on the BS2 side -- 47 to 1000 uF)

    Note also the BS2 control output current will be minimal -- the 'Module' uses the BS2 TTL signal to switch the separate supply high-current to the motor. Note also you *must* connect the motor ground, the BS2 ground, the BS2 supply ground, and the Motor supply ground if this is going to work.

    Note also, if you are building a robot with this, you *must* have a 'kill' switch on your robot.· With 12 volts and 8 amps, your BS2 will be controlling 100 watts of motor torque.· It's one thing if your little 20 oz Servo motor gets away from you, you can just pick it up.· With this much power, your robot can do some damage to itself or others before you can stop it unless you have a 'kill' switch.


    Post Edited (allanlane5) : 10/28/2004 9:24:55 PM GMT
  • cabojoecabojoe Posts: 72
    edited 2004-10-29 08:10
    The Motormind C is a nice option, but it's power handling capability is not great. I prefer to drive electronic speed controllers thru a servo controller. Since the Stamp can only do one thing at a time, if you don't use a servo controller the motors can't be driven while the stamp is processing sensor information. Using a servo controller solves this, as you can set the motors running and then go on to do more sensing while they run. The ESC you mention might only run in one direction, so beware of this if that's what you are wanting to get. By using a servo controller to control the ESC, you reduce the commands down to a simple SEROUT command, and it only takes one serial line from the stamp to control several motors.··
  • glasoglaso Posts: 38
    edited 2004-10-29 16:13
    I have a Pololu serial motor controller but I'm having problems to drive two small motors. After a while it begin to have strage response. I think that the termal protection i shutting down the controller.

    That's why I'm looking for other ways to control the motors like the R/C Speed controller. The man problem of the GWS ICS 300 is that it have only one direction.

    Does anyone have some tips to make the Pololu motor controller work better. I think that my motors are to far of drawing 2A of current.
  • cabojoecabojoe Posts: 72
    edited 2004-10-30 02:36
    Do your motors have their own dedicated power supply? Make sure you aren't trying to run the motors from the stamp's supply.
  • glasoglaso Posts: 38
    edited 2004-10-30 18:42
    YES, they have their own 6V power supply (4 AA batteries). I am using this motors with gearbox:

    http://www.pololu.com/products/tamiya/0061/
  • MatthewMatthew Posts: 200
    edited 2004-10-31 04:27
    glaso said...
    (That's why I'm looking for other ways to control the motors like the R/C Speed controller. The man problem of the GWS ICS 300 is that it have only one direction.)
    Check out this auction:

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=19168&item=5929612467&rd=1

    Analog foward and reverse. But beware, it is NOT made by Futaba, nor are the components. Handles up to 200 amps foward, and 100 amps in reverse!

    ·
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