/* irSwitch

This program reads an infrared detector and controls a relay on/off when an object is 
present near the IR sensor.

Parts of this code were inspire by examples in "Getting Started with Arduino"
By Massimo Banzi (Make:Books / O'Reilly Media, 2009)

Licensed under Creative Commons (BY-NC-SA). 
*/

//set variables
int switchPin = 3;
int irPin = A0;
int irVal = 0;
int state = 0;
int lastVal = 0;

void setup() {
  Serial.begin(9600);      //this is only necessary for troubleshooting or code tweaking.
  analogWrite(switchPin, 0);
}

void loop() {
 
  irVal = analogRead(irPin);      //set val to IR value
  
  // if the currtent value is below x, but it was previously higher than x: 
  if ((irVal <= 850) && (lastVal >= 850)) {           
   state = 1 - state;            // toggle state 
}  

//energize relay
if (state == 1) {            
 analogWrite(switchPin, 255);
 Serial.print("ON: ");
 Serial.println(irVal);
 Serial.println(state);

 
}
//de-energize relay
if (state == 0) {
  analogWrite(switchPin, 0);
  Serial.print("OFF: ");
 Serial.println(irVal);

}

lastVal = irVal;    // update last value to current value
delay(300);        // pause briefly so light flickers don't cause false triggers (like light between open fingers)


  /* test code- this prints info to the serial monitor during setup/testing.
  
  int sensor = analogRead(A0);
 // Serial.println(sensor);
 // delay(250);
 
//digitalWrite(3,  HIGH);
analogWrite(3, 255);
 Serial.println("ON");
 delay(1000);
//digitalWrite(3, LOW);
analogWrite(3, 0);
 Serial.println("OFF");
  delay(2000);
  */
}