LED blinking with delay

Projects General Guidance
1 
void setup() {
  // put your setup code here, to run once:
  pinMode(13, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(13, LOW);
  delay(1000);
  digitalWrite(13, HIGH); 
}

I have doubt after delay i tshould have to turn ON for long right, but it's turn OFF, if any one knows explain

2

Put another delay after the

Otherwise the LED turns on and loop() starts over right away and turns the LED off.

3

i know for blinking we have to put delay, i have to know why it's in LOW state because it should be in high state right

1 Like
4

A LED can be turned on by either a LOW or HIGH, see the two circuits D1 and D2 in the schematic.

1224×1108 280 KB

5

I didn't understand what are you trying to say

6

Hello sureshkumar_123

Try and checked this simplified sketch.

void setup() {
  // put your setup code here, to run once:
  pinMode(13, OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(13,!digitalRead(13));
  delay(1000);
}
7

As mentioned, add a second delay( ).

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(13, LOW);
  delay(1000);
  digitalWrite(13, HIGH); 
  delay(1000);
}

In the schematic, look at the symbols of the LEDs.

In D1 circuit, the cathode goes to the Arduino pin.

In D2 circuit, the anode goes to the pin.

8

Don’t be too worried, this is the first mistake that almost every user encounters when they write their own first blink program !

9

What is the meaning of "Blinking a LED"?

1. Turn ON the LED.
2. Wait for a while so that the brightness of the LED is visible.
3. Turn OFF the LED.
4. Wait for a while so that the brightness of the LED is visible.
5. repeat from Step-1.

If you omit Step-4, you will not see that the LED is OFF though there is a code in Step-3 to turn OFF the LED. The control instantly goes to Step-1 and the LED is ON again.

1 Like
10

why it's instantly going to step 1

11

That’s the way it works.

12

If not instatntly, then it will take 1 or 2 cycle time (0.0625 us or 0.1250 us with 16 MHz UNO) to reach at Step-1.

13

Okay Thanks, now i understood its turning OFF the LED but we can't see that right.

14

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