Elegoo Arduino Uno R3 – Blink Without Delay


By: Prix Hixson, Journalist

Today I will  be demonstrating one of the most basic Arduino Uno kit projects, Blink without delay. It can be as easy as connecting a wire to an LED light from a breadboard, and a resistor from a breadboard as on the tinkercad website (virtual example.)

For this project you will need:

  • 170 pin breadboard
  • 5 mm LED: red
  • Arduino UNO
  • ¬†Jumper wires: generic
  • USB-A to a Mini- USB cable
  • Resistor 221 ohm

Here is the code for Blink without delay:

void setup() {
// set the digital pin as output:
pinMode(ledPin, 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.
unsigned long currentMillis = millis();

if (currentMillis – previousMillis >= interval) {
// save the last time you blinked the LED
previousMillis = currentMillis;

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

// set the LED with the ledState of the variable:
digitalWrite(ledPin, ledState);

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