Trying to use an external interrupt as a stop button

Projects General Guidance
1

I have a relay that switches between two LEDs if I enter any value into the serial port.
My goal is to be able to start the loop by entering any key into the serial port, then when I press the button for the loop to stop, press the button again and the loop continues.

I made a simple loop, and if the interrupt pin receives a RISING signal it should go into a debounce function, then return to the loop.

I can get the loop to work by using the serial port, but as soon as the interrupt pin receives a signal it just starts the loop over again. If I press the button before I start the loop the LEDs will cycle as intended. I just need to reverse this essentially so that the button will cycle the LEDs then return to the loop.

Thanks for looking, any and all help is appreciated.

I made a little video to help explain what I'm trying to do:
https://drive.google.com/file/d/0B-RQblMzZ2qOdXcwUWRUd1Y5bDQ/view?usp=sharing

Here is my code:

int relay = 12; //sets relay to 12
int pause = 1500; //sets pause
const int buttonPin = 2; //sets button to 2
int relayState = HIGH; //sets the relay state to high
int buttonState; //the current reading of the button pin
int lastButtonState = LOW; //the previous reading from button pin
unsigned long lastDebounceTime = 0; //the last time the output pin was toggled
unsigned long debounceDelay = 50; //the deounce time;

void setup(){
Serial.begin(9600); //open serial port at 9600
Serial.println("Enter any key"); //takes the reading of any value
pinMode(relay,OUTPUT); //designates the relay pin as output
pinMode(buttonPin,INPUT); //designates the button pin as input
attachInterrupt(0,emrgcy,RISING); //sets pin 2 as the interrupt pin, if it recieves a high signal it will go into the emrgcy function

}

void loop() {
{ if(Serial.available()>0) //when the serial port receives a value greater than zero it will begin the
//loop to the relay
{
digitalWrite(relay,HIGH);
delay(pause);
digitalWrite(relay,LOW);
delay(pause);
}
}
}

void emrgcy(){
int reading = digitalRead(buttonPin); //read the state of the switch into a variable
digitalWrite(relay, relayState); //sets the relay to high

if (reading != lastButtonState){ //if the switch changed, due to noise or pressing;
lastDebounceTime = millis(); //reset the debouncing timer
}

if ((millis() - lastDebounceTime) > debounceDelay) { // whatever the reading is at, it's been there for longer
// than the debounce delay, so take it as the actual current state:
// if the button state has changed:
if (reading != buttonState){
buttonState = reading;

if(buttonState == HIGH){ //only toggle the LED if the new button state is high
relayState = !relayState;
}
}
}

digitalWrite(relay, relayState);
lastButtonState = reading;
}

2

Ditch the delay(1500); and you will not need to resort to interrupts - which just add another layer of complexity that will only confound you at this stage of the game.

Study and learn from the example sketch in the IDE called "Blink without delay", it will show you what you need to know using the internal clock system (which you already utilize in the debounce routine).

BTW, next, post your code using "code tags" (the </> icon) so your code looks like this:

int relay = 12;                      //sets relay to 12
int pause = 1500;                    //sets pause
const int buttonPin = 2;             //sets button to 2
int relayState = HIGH;               //sets the relay state to high
int buttonState;                     //the current reading of the button pin
int lastButtonState = LOW;           //the previous reading from button pin
unsigned long lastDebounceTime = 0;  //the last time the output pin was toggled
unsigned long debounceDelay = 50;    //the deounce time;

void setup() {
  Serial.begin(9600);                 //open serial port at 9600
  Serial.println("Enter any key");    //takes the reading of any value
  pinMode(relay, OUTPUT);             //designates the relay pin as output
  pinMode(buttonPin, INPUT);          //designates the button pin as input
  attachInterrupt(0, emrgcy, RISING); //sets pin 2 as the interrupt pin, if it recieves a high signal it will go into the emrgcy function

}

void loop() {
  { if (Serial.available() > 0)      //when the serial port receives a value greater than zero it will begin the
      //loop to the relay
    {
      digitalWrite(relay, HIGH);
      delay(pause);
      digitalWrite(relay, LOW);
      delay(pause);
    }
  }
}


void emrgcy() {
  int reading = digitalRead(buttonPin);    //read the state of the switch into a variable
  digitalWrite(relay, relayState);         //sets the relay to high

  if (reading != lastButtonState) {         //if the switch changed, due to noise or pressing;
    lastDebounceTime = millis();            //reset the debouncing timer
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {  // whatever the reading is at, it's been there for longer
    // than the debounce delay, so take it as the actual current state:
    // if the button state has changed:
    if (reading != buttonState) {
      buttonState = reading;

      if (buttonState == HIGH) {          //only toggle the LED if the new button state is high
        relayState = !relayState;
      }
    }
  }

  digitalWrite(relay, relayState);
  lastButtonState = reading;
}

and don't forget to auto-format it first in the IDE with "control-t".

Edit: You need to read the byte(s) out of the serial buffer before this program has a chance of working the way you intended. Look up "Serial.read" in the reference. Right now, after one character, the test is always true.