Changing from delay() to "without delay()"

Other Hardware LEDs and Multiplexing
19

I'm at work, so I can't test this code. Someone tell me if there is anything wrong here. This should blink four LEDs asynchronously.

*/ Blink Four LEDs Without Delay
  Adapted from Blink Without Delay
  by Steven J Greenfield, aka Polymorph
  Use however you like
/*


// constants won't change. Used here to 
// set pin numbers:
const int ledPin0 =  2;      // the number of the LED0 pin
const int ledPin1 =  3;      // the number of the LED1 pin
const int ledPin2 =  4;      // the number of the LED2 pin
const int ledPin3 =  5;      // the number of the LED3 pin

// Variables will change:
int ledState0 = LOW;             // ledState used to set the LED0
int ledState1 = LOW;             // ledState used to set the LED1
int ledState2 = LOW;             // ledState used to set the LED2
int ledState3 = LOW;             // ledState used to set the LED3

unsigned long previousMillis0 = 0;        // will store last time LED0 was updated
unsigned long previousMillis1 = 0;        // will store last time LED1 was updated
unsigned long previousMillis2 = 0;        // will store last time LED2 was updated
unsigned long previousMillis3 = 0;        // will store last time LED3 was updated

// the follow variables is a long because the time, measured in milliseconds,
// will quickly become a bigger number than can be stored in an int.
unsigned long interval0 = 1000;           // interval at which to blink LED0 (milliseconds)
unsigned long interval1 = 457;           // interval at which to blink LED1 (milliseconds)
unsigned long interval2 = 1020;           // interval at which to blink LED2 (milliseconds)
unsigned long interval3 = 742;           // interval at which to blink LED3 (milliseconds)

void setup() {
  // set the digital pin as output:
  pinMode(ledPin0, OUTPUT);    
  pinMode(ledPin1, OUTPUT); 
  pinMode(ledPin2, OUTPUT); 
  pinMode(ledPin3, OUTPUT);   
}

void loop()
{
  // here is where you'd put code that needs to be running all the time.

  // check to see if it's time to blink the LED; that is, if the 
  // difference between the current time and last time you blinked 
  // the LED is bigger than the interval at which you want to 
  // blink the LED.

  // save the current time so it doesn't change during an operation
  unsigned long currentMillis = millis();

  // LED0 
  if(currentMillis - previousMillis0 > interval0) {
    // save the last time you blinked the LED0 
    previousMillis0 = currentMillis;   

    // if the LED is off turn it on and vice-versa:
    if (ledState0 == LOW)
      ledState0 = HIGH;
    else
      ledState0 = LOW;

  //LED1
  if(currentMillis - previousMillis1 > interval1) {
    // save the last time you blinked the LED0 
    previousMillis1 = currentMillis;   

    // if the LED is off turn it on and vice-versa:
    if (ledState1 == LOW)
      ledState1 = HIGH;
    else
      ledState1 = LOW;

  //LED2
  if(currentMillis - previousMillis2 > interval2) {
    // save the last time you blinked the LED0 
    previousMillis2 = currentMillis;   

    // if the LED is off turn it on and vice-versa:
    if (ledState2 == LOW)
      ledState2 = HIGH;
    else
      ledState2 = LOW;

  //LED3
  if(currentMillis - previousMillis3 > interval3) {
    // save the last time you blinked the LED0 
    previousMillis3 = currentMillis;   

    // if the LED is off turn it on and vice-versa:
    if (ledState3 == LOW)
      ledState3 = HIGH;
    else
      ledState3 = LOW;

    // set the LEDs with the ledStates of the variable:
    digitalWrite(ledPin0, ledState0);
    digitalWrite(ledPin1, ledState1);
    digitalWrite(ledPin2, ledState2);
    digitalWrite(ledPin3, ledState3);

  }
}