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4 Phase Step Motor

Table of Contents

  1. The motor:
  2. Schematic
  3. Program and Library

I there, this is my first contribution for mbed platform.

Both program and library where made for working with a 4 Phase stepper motor like 28BYJ-48 that you can get on ebay for $5

Firsts thing first,

The motor:

/media/uploads/XtaticO/stepper01.jpg

as you can see the motor comes with an ULN2003 (like H-Bridge) control board...it's very helpful for setting things up.

How it works

/media/uploads/XtaticO/28byj48_01.jpg

2 sets of 2 serial coils , when activated in a determinate sequence they make the motor turn.

Table of Sequences

/media/uploads/XtaticO/28byj48_02.jpg

As you can see in the table, you just have to activate the coils in binary order.

Schematic

/media/uploads/XtaticO/4phase_schem.png

Program and Library

Program here

Import programStepper_4

Working with a 4 Phase Step Motor like 28BYJ-45 or others

Last commit 14 Jun 2012 by Nuno Sarmento

Library

http://mbed.org/users/XtaticO/libraries/sMotor/mblwtm

Here's the test code:

/*
############################################
##           sMotor v0.1 Test Program     ##
##          created by Samuel Matildes    ##
############################################
        ---- sam.naeec@gmail.com -----
This library was made for 4-Phase Stepper Motors
I don't take any resposability for the damage caused to your equipment.

*/

#include "mbed.h"
#include "sMotor.h"


Serial pc(USBTX, USBRX);
sMotor motor(p9, p10, p11, p12); // creates new stepper motor: IN1, IN2, IN3, IN4

int step_speed = 1200 ; // set default motor speed
int numstep = 512 ; // defines full turn of 360 degree
//you might want to calibrate this value according to your motor


int main() {

    //Credits
    printf("4 Phase Stepper Motor v0.1 - Test Program\r\n");
    printf("developed by Samuel Matildes\r\n");
    printf("\n\r");

    // Screen Menu
    printf("Default Speed: %d\n\r",step_speed);
    printf("1- 360 degree clockwise step\n\r");
    printf("2- 360 degree anticlockwise step\n\r");
    printf("3- 180 degree clockwise step\n\r");
    printf("4- 180 degree anticlockwise step\n\r");
    printf("5- Change Speed\n\r");

    while (1) {

        if (pc.readable()) { // checks for serial

            if (pc.getc()=='1')
                motor.step(numstep,0,step_speed); // number of steps, direction, speed

            if (pc.getc()=='2')
                motor.step(numstep,1,step_speed);

            if (pc.getc()=='3')
                motor.step(numstep/2,0,step_speed);

            if (pc.getc()=='4')
                motor.step(numstep/2,1,step_speed);

            if (pc.getc()=='5') {
                printf("Current Speed: %d\n\r", step_speed);
                printf("New speed: \n\r");
                pc.scanf("%d",&step_speed); // sets new speed
            }
        }
    }
}

I Hope it's useful for the community ;)

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