Help required in design & implementation of a simple ROBOT project using steperMotors

Discussion in 'The Projects Forum' started by Tanveer, Nov 14, 2008.

  1. Tanveer

    Thread Starter New Member

    Nov 14, 2008
    4
    0
    Hello Friends,

    I require urgent help in getting a setup through which we can control 4 stepper Motors using USB port on my PC.

    The components I have currently are:

    1. USB to RS232 (Serial) Convertor Card.
    2. A3982 IC - 4 Nos.
    3. 4 Stepper Motors.

    Stepper Motor Specifications
    Dimensions: 35mm x 35mm x 26mm
    Shaft diameter: 3mm
    Shaft length: 8.5mm
    Step angle: 1.8 Degrees
    Drive sequence: Bi polar
    Rated current 0.6Amps
    Resistance 3 Ohms
    Holding torque: 347gm/cm or 34mNm
    Inductance: 3.2mH
    Rotor inertia: 5g.cm2
    Weight: 105 Gms.

    4. My Laptop, where I intend to run a program to control the 4 Stepper Motors.

    I am completely novice in this field, but a strong enthusiast and hobbyist.
    I also require your suggestions / help in writing C code for this. Some sample programs on how to write & read from USB port would be sufficient, as I am quite good at C. This is intended to run on a XP OS.

    Please help me in making my idea a reality.

    Thanks In Advance.
    Tanveer
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Post up the schematic for the external circuit and the code you intend to use to operate those steppers, and we can get started.

    By the way, what will your robot look like and be able to do?
     
  3. Tanveer

    Thread Starter New Member

    Nov 14, 2008
    4
    0
    I am not good at Circuit Diagrams. Of late I have been longing to do electronics projects. This is my first attempt to it. I am hereby attaching the rough diagram how it is intended to look like ( step_motor.jpg ). Another attachment is taken from internet ( plotter.jpg ), which is how I want it look like.


    Basically, I am trying to plot the X & Y Axes on a Plane ( floor, where an object is kept ). Using these Axes, I will have to decide co-ordinates to hold the object etc..

    The idea is to have a Light Emitter on 1 motor & reciever on another motor. we will move the motors until the Reciever doesnt recieve the emitted light. PC would count the steps the motor moved. This marks X Axis. Similar procedure would be followed to determine the Y Axis.


    Sorry, If I am not upto the mark with the Circuit Diagrams. I am taking help from this forum to learn the same.

    Planning to write the code to drive this circuitry once I am completely done with the hardware.

    Thanks In Advance.

    Thanks & Regards,
    Tanveer
     
    Last edited: Nov 14, 2008
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Just a couple of observations:
    1) It looks like two stepper motors were used in that project for both the X and Y axis. I'm not certain why they elected to do that, but it certainly increases the complexity of the design, construction and programming of the project.

    It might be simplified a great deal if the motors on the far ends of the X and Y axis were replaced by idler pulleys.

    2) The precision in locating the object/target will be limited by the number of steps/revolution of your stepper motor in conjunction with the radius of the pulley. 1.8°/step means that you will have 200 steps per 1 complete revolution. If your pulley has a 1/4" radius (1/2" diameter), then each full step will (optimistically) move the belt 2 x pi x radius/200 = 0.007853975". Since the driver IC has half-step mode, you could get "roughly" twice that resolution.
     
  5. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
    1,438
    368
    I don't see why 2 motors per axis should increase complexity as both motors operate in unison and therefore can be connected in parallel. I suppose the advantage of 2 motors is twice the torque so less chance of missing a step.
     
  6. Tanveer

    Thread Starter New Member

    Nov 14, 2008
    4
    0
    using a belt.
     
    Last edited: Nov 14, 2008
  7. beenthere

    Retired Moderator

    Apr 20, 2004
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    A sensible addition to the design is some means of lifting the pen/pencil. That resolves the Etch a Sketch problem where all lines are connected.
     
  8. Tanveer

    Thread Starter New Member

    Nov 14, 2008
    4
    0
    I didnt get you..
     
    Last edited: Nov 14, 2008
  9. beenthere

    Retired Moderator

    Apr 20, 2004
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    Lifting the pen off the paper lets you draw individual lines. Leaving the pen on the paper means that all the lines are connected.
     
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