Turn on LED indicator when arduino uno ON for 5 second

Using Arduino Project Guidance
1

hi there,i try to give external LED indicator for Arduino board when i give voltage input 5v on arduino ,my external LED turn ON for 5 second and then turn off.i try use millis.but it likes i use delay().but my External LED still blinking. because i dont want blinking my LED.

unsigned long interval=1000; // the time we need to wait
unsigned long previousMillis=0; // millis() returns an unsigned long.
  
bool ledState = false; // state variable for the LED
  
void setup() {
 pinMode(13, OUTPUT);
 digitalWrite(13, ledState);
}
  
void loop() {
 unsigned long currentMillis = millis(); // grab current time
  
 // check if "interval" time has passed (1000 milliseconds)
 if ((unsigned long)(currentMillis - previousMillis) >= interval) {
   
   ledState = !ledState; // "toggles" the state
   digitalWrite(13, ledState); // sets the LED based on ledState
   // save the "current" time
   previousMillis = millis();
 }
}
2

Instead of toggling the LED state using

    ledState = !ledState; // "toggles" the state

simply set it to the state that you require it to be at, either HIGH or LOW

3

thanks uncle!!!....GOD bless YOU!!!!

4

what you mean Sr, could you explain more please

5

Which part don't you understand ?

6

(simply set it to the state that you require it to be at, either HIGH or LOW)

this one sr

7

I change this.

bool ledState = false;

with this :

bool ledState = true;

and change this:

ledState = !ledState;

with this:

ledState = false;

and this is what i want...hheheeh

8

The current code changes the state of teh LED when the period ends, so the LED blinks
If instead of

ledState = !ledState; // "toggles" the state

the code did

ledState = HIGH; // set the state to HIGH

Then the LED would stay HIGH after the period ends

NOTE: this is not the best way to do what is required but is simple to change the code to do it

9

thanks alot

10

thanks Sr

11

A smarter way to do what @ridhoazhar313 says he/she wants to do

boolean timing = true;

void setup()
{
  pinMode(13, OUTPUT);
  digitalWrite(13, LOW); //start with LED off
}

void loop()
{
  if (timing && millis() >= 5000) //test whether 5 seconds has elapsed
  {
    digitalWrite(13, HIGH); //turn LED on
    timing = false; //no need to check again
  }
}
12

great!!!.....thanks uncle!!

13

I try your smartest code uncle,but my LED keeps ON and doesnt turn off. :slightly_smiling_face:

14

The built in LED should start off and remain off for 5 seconds then turn on and stay on

Is that what it is doing ?

Your topic title says

Turn on LED indicator when arduino uno ON for 5 second

In post #1 you say

One is the opposite of the other
Which do you want ?

Change the values in the digitalWrite() code lines to change what the code does

15

The sketch by @UKHeliBob from reply #11 in Wokwi with the led on for 5 seconds, then off:

16

ya,,,im sory..youre right..hahaha...thanks !!! :sweat_smile: :sweat_smile: :sweat_smile:

17

So which was it you wanted ?

18

its good,i have new knowladge to make simple code,and of course i need all...actually.Alhamdullillah!!!

19

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