control stepper with potentiometer threw motor shield

Projects Programming
1

I'm working on a project that uses a 12 volt stepper motor and I need some way to control it, not the speed but the direction. I'm using an arduino uno with a arduino motor shield attached to it. I've been messing with using a potentiometer, but I'm open to any ideas. I'm stuck on working with the code to this project and need help or suggestions any thing would be helpful.

2

I presume you've tried the MotorKnob example sketch?

3

yes, I was hoping on changing that code to make it use the same pins as the motor shield and other slight changes but the motor steps wildly with out any inputs from the potentiometer.

4

jiokl:
yes, I was hoping on changing that code to make it use the same pins as the motor shield and other slight changes but the motor steps wildly with out any inputs from the potentiometer.

Did you figure this out?

I have an Arduino Uno, with a Seeed Motor Shield on top. I've got my 12v power source and my stepper motor running using Seeed StepperMotorDemo. Code below.

I want to add on two switches and a potentiometer.

One switch would control direction
One switch would control on and off
The Potentiometer would control speed of the stepper motor.

Can anyone point me in the right direction? Does my Motor Shield have enough inputs/outputs to do this?

Please help

//  Demo function:The application method to drive the stepper motor.
//  Hareware:Stepper motor - 24BYJ48,Seeed's Motor Shield v2.0
//  Author:Frankie.Chu
//  Date:20 November, 2012
#define MOTOR_CLOCKWISE      0
#define MOTOR_ANTICLOCKWISE  1
/******Pins definitions*************/
#define MOTORSHIELD_IN1 8
#define MOTORSHIELD_IN2 11
#define MOTORSHIELD_IN3 12
#define MOTORSHIELD_IN4 13
#define CTRLPIN_A 9
#define CTRLPIN_B 10

const unsigned char stepper_ctrl[]={0x27,0x36,0x1e,0x0f};
struct MotorStruct
{
int8_t speed;
uint8_t direction;
};
MotorStruct stepperMotor;
unsigned int number_of_steps = 200;
/**********************************************************************/
/*Function: Get the stepper motor rotate                               */
/*Parameter:-int steps,the total steps and the direction the motor rotates.*/
/* if steps > 0,rotates anticlockwise,     */
/* if steps < 0,rotates clockwise.             */
/*Return: void                            */
void step(int steps)
{
int steps_left = abs(steps)*4;
int step_number;
int millis_delay = 60L * 1000L /number_of_steps/(stepperMotor.speed + 50);
if (steps > 0) 
{
stepperMotor.direction= MOTOR_ANTICLOCKWISE;
step_number = 0; 
}
   else if (steps < 0) 
{
stepperMotor.direction= MOTOR_CLOCKWISE;
step_number = number_of_steps;
}
else return;
while(steps_left > 0) 
{
PORTB = stepper_ctrl[step_number%4];
delay(millis_delay);
if(stepperMotor.direction== MOTOR_ANTICLOCKWISE)
{
step_number++;
   if (step_number == number_of_steps)
    step_number = 0;
}
else 
{
step_number--;
   if (step_number == 0)
    step_number = number_of_steps;
}
steps_left --;

}
}
void initialize()
{
pinMode(MOTORSHIELD_IN1,OUTPUT);
pinMode(MOTORSHIELD_IN2,OUTPUT);
pinMode(MOTORSHIELD_IN3,OUTPUT);
pinMode(MOTORSHIELD_IN4,OUTPUT);
pinMode(CTRLPIN_A,OUTPUT);
pinMode(CTRLPIN_B,OUTPUT);
stop();
stepperMotor.speed = 25;
stepperMotor.direction = MOTOR_CLOCKWISE;
}
/*******************************************/
void stop()
{
/*Unenble the pin, to stop the motor. */
digitalWrite(CTRLPIN_A,LOW);
   digitalWrite(CTRLPIN_B,LOW);
}

void setup()
{
initialize();//Initialization for the stepper motor.
}

void loop()
{
step(200);//Stepper motors rotate anticlockwise 200 steps.
delay(1000);
step(-200);//Stepper motors rotate clockwise 200 steps.
delay(1000);
}