Two LEDs

In class it was asked how to go about blinking two LEDs on two different digital pins but at different speeds. What has to be done is that the time has to be broken down into segments. So for our example, the green led was to come on for 1 second and stay off for 1 second while the red LED fashes on and off 10 times in 1 second. This meant we had to turn on the red LED for 50ms and off for 50ms and do this 10 times. (50ms+50ms=100ms and 100ms x 10=1000ms or 1 second.) Instead of just turning on the green LED and delaying for 1 second, we run a for loop to flash the red LED for 1 second instead and then turn off the green LED, flash the red 10 times again and then start the loop all over again. Clear as mud, huh?

/*  This example was a way to blink one LED slowly

    while a second blinks quickly. Its important to think

    about the timing in a top down program.

*/

int redLED = 13;                 // LED on digital pin 13

int greenLED = 12;               // LED on digital pin 12

void setup()                     // run once

{

  pinMode(redLED, OUTPUT);       // sets pin 13 as output

  pinMode(greenLED, OUTPUT);     // sets pin 12 as output

}

void loop()                      // run over and over again

{

  digitalWrite(greenLED, HIGH);  // turns the green on

  for(int i=0; i<10; i++)        // blinks red 10 times

  {

    digitalWrite(redLED, HIGH);  // turns the red on

    delay(50);

    digitalWrite(redLED, LOW);   // turns the red off

    delay(50);

  }

  digitalWrite(greenLED, LOW);   // turns the green off

  for(int i=0; i<10; i++)        // blinks red 10 times

  {

    digitalWrite(redLED, HIGH);  // turns the red on

    delay(50);

    digitalWrite(redLED, LOW);   // turns the red off

    delay(50);

  }

}