Interrupt code not working

columbus1231

Hello, I got this stepper motor running code and it works fine. However I am trying to write a code to enable me to pause it and turn on led on pin 13, when I press a button and then have it continue running where it left off when I release the button. I tried by attaching an interrupt but it didn’t work. The modifications I made are in bold. Anyone know what I did wrong? I’m using an Arduino mega 2560. Here is the code below. Any help will be appreciated.

//////////////////////////////////////////////////////////////////
//©2011 bildr
//Released under the MIT License - Please reuse change and share
//Using the easy stepper with your arduino
//use rotate and/or rotateDeg to controll stepper motor
//speed is any number from .01 -> 1 with 1 being fastest - 
//Slower Speed == Stronger movement
/////////////////////////////////////////////////////////////////
#include <avr/interrupt.h>

# define LED_PIN 13
# define SWITCH_PIN 5      // pin 18 for interrupt on Arduino mega 2560

#define DIR_PIN 2
#define STEP_PIN 3

void setup() { 
  pinMode(DIR_PIN, OUTPUT); 
  pinMode(STEP_PIN, OUTPUT); 
  pinMode(LED_PIN, OUTPUT);
  // switch input
  pinMode(18, INPUT);
  // attach the interrupt on pin 18
  attachInterrupt(SWITCH_PIN, light, LOW);
} 

void light() {
  digitalWrite(LED_PIN, HIGH);
}

void loop(){ 

  //rotate a specific number of degrees 
  rotateDeg(360, 1); 
  delay(1000);

  rotateDeg(-360, .1);  //reverse
  delay(1000); 


  //rotate a specific number of microsteps (8 microsteps per step)
  //a 200 step stepper would take 1600 micro steps for one full revolution
  rotate(1600, .5); 
  delay(1000); 

  rotate(-1600, .25); //reverse
  delay(1000); 
}



void rotate(int steps, float speed){ 
  //rotate a specific number of microsteps (8 microsteps per step) - (negitive for reverse movement)
  //speed is any number from .01 -> 1 with 1 being fastest - Slower is stronger
  int dir = (steps > 0)? HIGH:LOW;
  steps = abs(steps);

  digitalWrite(DIR_PIN,dir); 

  float usDelay = (1/speed) * 70;

  for(int i=0; i < steps; i++){ 
    digitalWrite(STEP_PIN, HIGH); 
    delayMicroseconds(usDelay); 

    digitalWrite(STEP_PIN, LOW); 
    delayMicroseconds(usDelay); 
  } 
} 

void rotateDeg(float deg, float speed){ 
  //rotate a specific number of degrees (negitive for reverse movement)
  //speed is any number from .01 -> 1 with 1 being fastest - Slower is stronger
  int dir = (deg > 0)? HIGH:LOW;
  digitalWrite(DIR_PIN,dir); 

  int steps = abs(deg)*(1/0.225);
  float usDelay = (1/speed) * 70;

  for(int i=0; i < steps; i++){ 
    digitalWrite(STEP_PIN, HIGH); 
    delayMicroseconds(usDelay); 

    digitalWrite(STEP_PIN, LOW); 
    delayMicroseconds(usDelay); 
  } 
}