// vim:ft=arduino
/*
  CribCandle
  version 0.1  October 18, 2012
  Author : Michel Baily
  
  Try to simulate random lighting of a wood fire for Christmas Crib illumination
  
  For that purpose, we use 3 LEDs (2 Yellow, 1 Red) blinking randomly
 */
 
 #define LED_COUNT 3
 
 // Define power excusion. 
 // Half excursion allows to have a possible négative random value...
 #define HALF_POWER_EXCURSION 40
 #define POWER_EXCURSION (HALF_POWER_EXCURSION*2)
 
 // Define analogWrite range...
 #define MIN_VALUE 10
 #define MAX_VALUE 240
 #define INITIAL_VALUE 125
 
 #define DELAY 70
 
 //Array containing led pin numbers
 int ledPins[LED_COUNT] = {9,10,11};
 //Array containing led current values
 int ledValues[LED_COUNT] = {INITIAL_VALUE, INITIAL_VALUE, INITIAL_VALUE};


//Initial setup...
void setup() {                
  // initialize the led pins as output.
  for(int i=0;i<LED_COUNT;i++) { pinMode(ledPins[i], OUTPUT); }
}

//Main loop
void loop() {
  for(int i=0; i<LED_COUNT; i++) 
  {
    //Compute the new value as the previous one + random number
    ledValues[i] += random(POWER_EXCURSION) - HALF_POWER_EXCURSION;
    
    //ensure we stay in acceptable range
    ledValues[i] = max( min(ledValues[i], MAX_VALUE), MIN_VALUE);
    
    //Update Led value
    analogWrite( ledPins[i], ledValues[i] );
  } 
  delay(DELAY);              // wait for a few
}