In this tutorial, we’ll build the simplest Arduino project called blinking an LED.
Components Required
- Arduino Uno (or compatible board)
- 1 × LED
- 1 × 220Ω resistor
- Jumper wires
- USB cable
Understanding the LED Pins
Before wiring, check the LED:
- Long leg → Positive (Anode)
- Short leg → Negative (Cathode)
Circuit connection
Follow these steps:
- Connect the long leg to one end of the resistor
- Connect the other end of the resistor to pin 13 on Arduino
- Connect the short leg to GND of Arduino
Upload the code
void setup() {
pinMode(LED_BUILTIN, OUTPUT); // Set built-in LED pin as output
}
void loop() {
digitalWrite(LED_BUILTIN, HIGH); // Turn LED ON
delay(1000); // Wait 1 second
digitalWrite(LED_BUILTIN, LOW); // Turn LED OFF
delay(1000); // Wait 1 second
}Open Arduino IDE and paste the above code.
Then –
- Select the correct board (Arduino Uno)
- Select the correct COM port
- Click Upload
How this code works?
pinMode(13, OUTPUT)→ tells Arduino to control that pindigitalWrite(HIGH)→ sends voltage → LED ONdigitalWrite(LOW)→ no voltage → LED OFFdelay()→ controls timing
You can see the LED blinking and this simple project is the foundation of almost every embedded system. Once you understand this, you’re ready to build more meaningful electronics projects.