/*
 * randomly flickering LEDs
 */

int ledPin[] = {
  5, 6, 9, 10, 11};              // pwm pins only
int ledState[5];                 // last state of each led
long randNumber;

void setup() {
  for (int i=0; i<=4; i++){      // set each led pin as an output
    pinMode(ledPin[i], OUTPUT);	 
  }
  randomSeed(analogRead(0));     // seed the rnd generator with noise from unused pin

  for (int i=0; i<=4; i++){      // init each led with a random value
    ledState[i] = random(20, 201);
  }
}

void loop(){ 
  for (int i=0; i<=4; i++){                  // for each led:
    analogWrite(ledPin[i], ledState[i]);     // set the pwm value of that pin determined previously
    randNumber = random(-40, 41);            // generate new random number and add that to the current value
    ledState[i] += randNumber;               // that range can be tweaked to change the intensity of the flickering
    if (ledState[i] > 200) {                 // clamp the limits of the pwm values so it remains within
      ledState[i] = 200;                     // a pleasing range as well as the pwm range
    }
    if (ledState[i] < 10) {
      ledState[i] = 10;
    }
  }
  delay(100);    // the delay between changes
}