C programming a stepper motor

Rbolick · 2013-10-23 13:07

I am trying to teach students as how to connect a unipolar stepper motor (Mouser Part # 619-27964) to the Parallax Propeller Activity board using a ULN2003 darlington chip. Once connected in the breadboard I need help in programming it to step at various torques. The information on the torques are on the steppers data sheet, but I am not a very good C programmer.

Can someone help with a very simple C program( which libraries are needed and where to obtain them, and where to put then on my computer) that is documented so I can follow and make alterations in torques?
Thanks

NWCCTV · 2013-10-23 19:37

I think I have some really simple C code for stepper motors that I did some years ago. IIRC, I used the program to communicate to PBasic and a Stamp through C. I know for a fact I have this for VB. Give me a bit to search my Server database for my older archived projects. I can't guarantee that any of it is documented but it may be a start.

Edit: I am not sure if the attached project will help you out or not. It is in VC# and when I tried to build I got some usb errors. The file says it was created August of this year but I know that is wrong since it has been at least a couple years since I worked on it. I will try to find my notes on what I was doing and trying to accomplish so I can help you out more.

mnastasi · 2014-09-13 21:18

any progress on parallax or manufacturer release little step c code ? thanks for your help

dgately · 2014-09-14 09:19

mnastasi wrote: »

any progress on parallax or manufacturer release little step c code ? thanks for your help

Just for fun, I translated Parallax's example BS2 Stepper code (@: http://www.parallax.com/downloads/stepper-motor-basic-stamp-example-code) to C. It uses just the simple tools library in SimpleIDE. Not sure if this actually works, as I don't have the ULN chip but it's an example of BASIC to C translation for a stepper motor...

// C version of BS2 Stepper program
// =========================================================================
//
//   File...... Stepper_27964.BS2
//   Purpose... Simple Stepper Motor Demo
//   Author.... Parallax, Inc. (Copyright (c) 2004, All Rights Reserved)
//   E-mail.... support@parallax.com
//   Started...
//   Updated... 18 MAR 2004
//
//   {$STAMP BS2}
//   {$PBASIC 2.5}
//
// =========================================================================
// -----[ Program Description ]---------------------------------------------
//
// Simple stepper motor (Parallax #27964) demonstration rotates motor one
// full revolution clockwise, pauses, then rotates one full revolution
// counter-clockwise. After another short pause, the process repeats.
//
// Connections:
// -----------------------------------------------
// P4 -> ULN2003.1, ULN2003.16 -> Phase 1 (Black)
// P5 -> ULN2003.2, ULN2003.15 -> Phase 2 (Orange)
// P6 -> ULN2003.3, ULN2003.14 -> Phase 3 (Brown)
// P7 -> ULN2003.4, ULN2003.13 -> Phase 4 (Yellow)
//
// Note: Do NOT connect stepper motor wires directly to the BASIC Stamp.
//       See Parallax documentation for complete connection schematic.

#include "simpletools.h"

// -----[ Global Variables ]------------------------------------------------

int idx;           // loop counter
int stpIdx;        // step pointer
int stpDelay;      // delay for speed control

//Steps   DATA    %0011, %0110, %1100, %1001
char Steps[] = {0b0011, 0b0110, 0b1100, 0b1001};

void Step_Fwd();
void Step_Rev();
void Do_Step();

// -----[ Initialization ]--------------------------------------------------
void Setup()
{
  //DIRB = %1111                  // make P4..P7 outputs
  set_directions(7, 4, 16);       // make P4..P7 outputs
  stpDelay = 15;                  // set step delay, 15 msecs
}

// -----[ Program Code ]----------------------------------------------------
int main(void)
{
  Setup();
  
  while(1)                           // repeat forever
  {
    for (idx=1; idx < 49; idx++)     // one revolution
      Step_Fwd();                    // rotate clockwise


    pause(500);                      // wait 1/2 second


    for (idx=1; idx < 49; idx++)     // one revolution
      Step_Rev();                    // rotate counter-clockwise


    pause(500);                      // wait 1/2 second
  }  
}

// -----[ Functions ]-------------------------------------------------------

// Turn stepper clockwise one full step (7.5 degrees)
void Step_Fwd()
{
  stpIdx = stpIdx + 1 % 4;           // point to next step
  Do_Step();
}

// Turn stepper counter-clockwise one full step (7.5 degrees)
void Step_Rev()
{
  stpIdx = stpIdx + 3 % 4;           // point to previous step
  Do_Step();
}

// Read new step data and output to pins
void Do_Step()
{
  //READ (Steps + stpIdx), Phase     // output new phase data
  set_outputs(3, 0, Steps[stpIdx]);
  pause(stpDelay);                   // pause between steps
}

dgately

C programming a stepper motor

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