View source for IDPL - 3: LED Blinking with Arduino Uno

== IDPL - 3: LED Blinking with Arduino Uno ==

=== Objective ===
To interface an LED with Arduino Uno and write a program to blink the LED at a fixed time interval.

=== Required Components ===

* Arduino Uno
* LED
* 220 Ω resistor
* Breadboard
* Jumper wires
* USB cable

=== Circuit Diagram ===

<!-- IMAGE PLACEHOLDER:
Suggested image: Circuit diagram showing Arduino Uno digital pin 8 connected to a 220 Ω resistor, then to the LED anode. LED cathode connected to GND.
Suggested filename: Arduino-LED-blinking-circuit.png
-->

=== Board Connections ===

<!-- IMAGE PLACEHOLDER:
Suggested image: Actual board connection photo showing Arduino Uno, breadboard, LED, 220 Ω resistor, and jumper wires with the LED connected to digital pin 8 and GND.
Suggested filename: Arduino-LED-blinking-board-connection.png
-->

=== Pin Connections ===

{| class="wikitable" style="text-align:center; width:100%;"
! Component
! Connection
|-
| LED Anode (+)
| Arduino Digital Pin 8 (through 220 Ω resistor which is already fitted on the kit)
|-
| LED Cathode (-)
| Arduino GND
|}

=== Working Principle ===

The Arduino sets digital pin 8 as an output. When the pin is set to '''HIGH''', approximately 5 V is applied to the LED through the resistor, causing the LED to glow.

When the pin is set to '''LOW''', the voltage is removed and the LED turns OFF.

The '''220 Ω resistor''' limits the current flowing through the LED and protects both the LED and Arduino output pin.

The program alternates between HIGH and LOW with a delay of 1 second, producing a continuous blinking effect.

=== Arduino Code ===

<pre>
// © 2026, Cognifront. Member of The IoT Kits Family.

// Experiment: LED Blinking with Arduino Uno

int ledPin = 8;

void setup() {
  // Set LED pin as an output
  pinMode(ledPin, OUTPUT);
}

void loop() {
  // Turn LED ON
  digitalWrite(ledPin, HIGH);
  delay(1000);

  // Turn LED OFF
  digitalWrite(ledPin, LOW);
  delay(1000);
}
</pre>

=== Observation ===

* The LED turns ON for 1 second.
* The LED turns OFF for 1 second.
* The ON/OFF cycle repeats continuously.
* The LED therefore appears to blink at a regular interval.

=== Result ===

The LED was successfully interfaced with Arduino Uno and programmed to blink continuously at a 1-second interval.

=== Conclusion ===

This experiment demonstrates basic digital output control using Arduino Uno. It introduces the use of '''pinMode()''', '''digitalWrite()''', and '''delay()''' functions for controlling an external electronic component.