Millis Delay Example For Arduino

What is delay () ?

We all are familiar with delay() function in Arduino. For example delay(1000) will give a 1 second delay to the program code. The major disadvantage of this function is that it will pause the entire code from execution. The delay() function is known as 'Code Blocking'. What it does is pauses the code for a set amount of time. The time it pauses for is indicated within the brackets in milliseconds. Eg: delay(1000) will pause the code for 1 second. This will affect some large code execution when some sensors or LCDs are interfaced. 

Here comes the concept of millis delay function. The millis() function is nothing like delay(). It helps us time events without pausing the code. The Arduino Reference for millis() says it: Returns the number of milliseconds passed since the Arduino board began running the current program.

How To Use millis() Instead of delay()?

After reading above, we have covered why and when you should use millis(), and now we get to the all-important how. How to use millis() to time your events instead of using delay() to pause your events.

Instead of pausing your program, what you need to do is write a small equation to check if the correct amount of time has passed, if the correct amount of time has passed, do the event, or else keep looping.

Let's rewrite the 'Blink' project, and convert it from using delay() to using millis(). After this code, we will break down what is going on.

Here is one example which gives 1 second (1000 microseconds) delay using millis delay. Basically Pin number 13 of Arduino has connected an in built led. The programme blinks the above led. Please refer through the code. I have used millisDelay.h library to write the code. For more about the library and syntax, visit here.

Code :

#include <millisDelay.h>

int LedPin = 13;           //Inbuilt Led is assigned

millisDelay TimeDelay;

bool LedOn = false;

 

void setup(){

  Serial.begin(9600);

  TimeDelay.start(1000);   //Give 1 second delay

  pinMode(LedPin, OUTPUT); 

}

 

void loop(){

  if (TimeDelay.justFinished()) {

        TimeDelay.repeat();

        LedOn = !LedOn;

        if (LedOn) {

          digitalWrite(LedPin, HIGH);

  } else {

          digitalWrite(LedPin, LOW);

    }

  }

}