SolderingIronBOff.ino

/*
  Button / SolderingIronBOff 
  Automatically turns off soldering station.
 
 Turns on the power switch tail (also the LED) 
 connected to digital pin 1.6, 
 when pressing a pushbutton attached to pin 2. 
 
 Automatically times out when it reaches a threshold.
 
 Pressing it again resets the timer.
 
 A warning LED on Pin 1.0 is lit when 
 we have < 20% time left.
 
 created 2005
 by DojoDave <http://www.0j0.org>
 modified 30 Aug 2011
 by Tom Igoe
 modified Apr 27 2012
 by Robert Wessels
 modified Apr 12 2016
 by Huan Truong
 
 This example code is in the public domain.
 
 http://www.arduino.cc/en/Tutorial/Button
 */

// constants won't change. They're used here to 
// set pin numbers:
const int buttonPin = PUSH2;     // the number of the pushbutton pin
const int powerSwitchPin =  GREEN_LED;      // the number of the pwer switch tail
const int warningLedPin =  RED_LED;      // the number of the warning LED

const unsigned long maxTimeOut = 1000UL * 60UL * 15UL;
const unsigned long warningMaxTimeOut = maxTimeOut / 10UL * 8UL;

volatile int buttonState;             // the current reading from the input pin
volatile int lastButtonState = LOW;   // the previous reading from the input pin

// the following variables are long's because the time, measured in miliseconds,
// will quickly become a bigger number than can be stored in an int.
volatile unsigned long lastDebounceTime = 0;  // the last time the output pin was toggled
volatile unsigned long debounceDelay = 5;    // the debounce time; increase if the output flickers

volatile unsigned long timeOut = 0;
volatile unsigned long warningTimeOut = 0;

void setup() {
  // initialize the LED pin as an output:
  pinMode(powerSwitchPin, OUTPUT);      
  digitalWrite(powerSwitchPin, LOW);  
  pinMode(warningLedPin, OUTPUT);    
  digitalWrite(warningLedPin, LOW);  
  // initialize the pushbutton pin as an input:
  pinMode(buttonPin, INPUT_PULLUP);     
  //Serial.begin(9600);
  //Serial.println("Soldering station auto-off 1.0 - Written by Huan Truong 2016");
}

void loop(){
  // read the state of the switch into a local variable:
  int reading = digitalRead(buttonPin);

  // check to see if you just pressed the button 
  // (i.e. the input went from HIGH to LOW),  and you've waited 
  // long enough since the last press to ignore any noise:  

  // If the switch changed, due to noise or pressing:
  
  if (reading != lastButtonState) {
    // reset the debouncing timer
    lastDebounceTime = millis();
  } 
  
  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:
    buttonState = reading;
    
    // check if the pushbutton is pressed.
    // if it is, the buttonState is LOW
    if (buttonState == LOW) {     
      // turn LED on:    
      digitalWrite(powerSwitchPin, HIGH); 
      digitalWrite(warningLedPin , LOW); 
      // set the timeout to be a point in future
      timeOut = millis() + maxTimeOut;
      warningTimeOut = millis() + warningMaxTimeOut;
      //Serial.println("Turned the soldering station on!");
    }
    
  }


  if (millis() > timeOut) {
    // Turn station off if timeout  
    digitalWrite(powerSwitchPin, LOW); 
    digitalWrite(warningLedPin , LOW);
  } else if (millis() > warningTimeOut) {
    // Turn warning LED off if we have less than 20% remaining time.
    digitalWrite(warningLedPin , HIGH);
  }
  
  lastButtonState = reading;
  
  //Serial.print("Time left: ");
  //Serial.println(timeOut);
}