010 (again) Flicker Sketch

This sketch shows the LED going on for 12 millseconds then off for 13 millisecond intervals. In ambient light, I can just see the flickering - I find this more distinguishable than when the light is on for 13 millseconds then off for 12 milliseconds:

/*
  Flicker
 
 Turns on an LED on for 12 millisecond, then off for 13 millisecond, repeatedly.
 
 The circuit:
 * LED connected from digital pin 13 to ground.
 
 * Note: On most Arduino boards, there is already an LED on the board
 connected to pin 13, so you don't need any extra components for this example.
 
 
 Created 5th March 2010
 By Mike Goodwin
 
 */

int ledPin =  13;    // LED connected to digital pin 13

// The setup() method runs once, when the sketch starts

void setup()   {                
  // initialize the digital pin as an output:
  pinMode(ledPin, OUTPUT);     
}

// the loop() method runs over and over again,
// as long as the Arduino has power

void loop()                     
{
  digitalWrite(ledPin, HIGH);   // set the LED on
  delay(12);                    // wait for 12 milliseconds
  digitalWrite(ledPin, LOW);    // set the LED off
  delay(13);                    // wait for 13 milliseconds
}