I want my stepper motor to switch speed while traveling (not acceleration wise)

Question

I have this project I'm working on where I'll need the speed of the stepper motor to change set speed at a certain distance, I just can't figure out a way to do it. I'm using arduino and a stepper motor, this is the current code.

#include <AccelStepper.h>

AccelStepper stepper1(AccelStepper::FULL4WIRE, 0, 1, 2, 3);

void setup()
{  
    stepper1.setMaxSpeed(200.0);
    stepper1.setAcceleration(400.0);
    stepper1.moveTo(5000);

}

void loop()
{
    // Change direction at the limits
    if (stepper1.distanceToGo() == 0)
    stepper1.moveTo(-stepper1.currentPosition());
    stepper1.run();

What I want it to do basically is to first moveTo(2500) at the current speed 200 then after 2500 I want it to increase speed to 400. After it has moved 5000 it turns and moves back to position but that's implemented already.

Answer 1

For this task; increase speed when a certain distance is reached.

I would use encoders on the wheels which will workout the distance travelled and when the target distance is reached then increase speed.

Answer 2

You can do what yu want with the standard arduino "Stepper" library. You are using something called "accelsteper.h".

Using the standard one....

This c-like psudocode will run a motor at some speed for 2000 steps then run and some other speed for 4000 steps and then go back an do it again.

loop{ setspeed(speed1) step(2000) setspeed(speed2) step(4000) }

Look here for details on the standard stepper library http://arduino.cc/en/Reference/Stepper

Get this to work FIRST. then make it nicer if you need to. for example place a half way between speed in there like this "set speed((speed1+speed2)/2). and run a few steps.

Answer 3

#include <AccelStepper.h>

//AccelStepper Xaxis(1, 2, 5); // pin 2 = step, pin 5 = direction
AccelStepper Xaxis(1, 12, 6); // pin 3 = step, pin 6 = direction

void setup() 
{
  Xaxis.setMaxSpeed(4000);

  //Xaxis.setSpeed(10);
  pinMode (3, INPUT);
}

void loop() 
{  
   //Xaxis.runSpeed();
   if (digitalRead (3) == HIGH)
   {
     //Xaxis.stop();
     Xaxis.setSpeed(20);

     Xaxis.runSpeed();
   }

   if (digitalRead (3) == LOW)
   {
     Xaxis.runSpeed();
     Xaxis.setSpeed(-10);  // - sign change direction !!!!!
   }
}