In this lesson, we’ll take our Blinky Light to the next level by adding a button to control the LED. Now, you’ll be able to turn the light on and off with a simple press!

Objective: Learn how to use a button to control an LED.

Materials:

• Arduino Uno board
• Breadboard
• LED (any color)
• 220-ohm resistor
• Push button
• Jumper wires
• Computer with Arduino IDE software installed

Step 1: Connecting the Button

1. Find the two legs of the push button: One is normally open (NO) and the other is normally closed (NC).
2. Connect the NO leg of the button to a digital input pin on the Arduino: We’ll use pin 2 in this lesson.
3. Connect the other leg of the button to a ground rail on the breadboard: This completes the button’s circuit.

Step 2: Connecting the LED and Resistor (Review)

1. Connect the LED and resistor as you did in Lesson 1: Make sure the LED’s longer leg is connected to a power rail and the resistor’s other leg is connected to the same row as the LED’s shorter leg.

Step 3: Connecting the Arduino (Review)

1. Connect the LED’s longer leg to digital pin 13 on the Arduino: This is the output pin for the LED.

Step 4: Programming the Arduino

1. Open the Arduino IDE.
2. Copy and paste the following code:

const int buttonPin = 2; // Button connected to pin 2
const int ledPin = 13;   // LED connected to pin 13

void setup() {
  pinMode(buttonPin, INPUT); // Set button pin as input
  pinMode(ledPin, OUTPUT); // Set LED pin as output
}

void loop() {
  if (digitalRead(buttonPin) == HIGH) { // Check if button is pressed
    digitalWrite(ledPin, HIGH); // Turn LED on
  } else {
    digitalWrite(ledPin, LOW); // Turn LED off
  }
}

1. Upload the code to the Arduino board.

Step 5: Testing the Circuit

1. Press the button: You should see the LED turn on.
2. Release the button: The LED should turn off.

Congratulations! You’ve created a button-controlled LED circuit!

Let’s Experiment:

• Add a delay: Try adding a delay in the loop() function to make the LED stay on for a short time after the button is pressed.
• Change the LED color: Try using a different colored LED.

Keep exploring and have fun with Arduino!