💡 2. Project Title: Turn LED ON using Push Button (Arduino)

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🧠 Project Description

This simple project demonstrates how to use a push button to control an LED.
When you press the button, the LED connected to pin 8 will turn ON; when you release it, the LED will turn OFF.

This teaches you the concept of digital input (button) and digital output (LED) — the base of all Arduino-controlled devices.

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⚙️ Components Required

Component	Quantity	Description
Arduino UNO / Nano	1	Main microcontroller board
LED	1	Output device
220Ω Resistor	1	Protects the LED from high current
Push Button	1	Used as input switch
Breadboard	1	For circuit setup
Jumper Wires	Few	For connections

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🔌 Circuit Connections (Based on Your Wiring)

Component	Arduino Pin	Other Connection
LED (Anode +)	D8	Through 220Ω resistor
LED (Cathode −)	GND	—
Push Button	D7	One end connected to D7
Push Button	5V	Other end connected to +5V
Internal Pull-Down	GND	Managed via software logic

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⚙️ Circuit Explanation

• When the push button is not pressed, the input pin (D7) reads LOW (0).
• When you press the button, it connects 5V to pin D7, making it HIGH (1).
• The Arduino detects this HIGH signal and turns the LED ON by sending a HIGH output to pin D8.
• Once released, the pin returns LOW, and the LED turns OFF.

🧩 You are using the Arduino’s INPUT_PULLDOWN logic manually (since the button connects to 5V).
If your board doesn’t have a physical pulldown resistor, you can use software logic or wire one (optional).

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💻 Arduino Code

// Turn LED ON using Push Button
int ledPin = 8;      // LED connected to pin 8
int buttonPin = 7;   // Push button connected to pin 7
int buttonState = 0; // Variable to store button state

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

void loop() {
  buttonState = digitalRead(buttonPin); // Read button input

  if (buttonState == HIGH) {
    digitalWrite(ledPin, HIGH); // Turn LED ON
  } else {
    digitalWrite(ledPin, LOW);  // Turn LED OFF
  }
}

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🧠 Code Explanation

Line	Description
int ledPin = 8;	LED connected to digital pin 8
int buttonPin = 7;	Push button connected to pin 7
pinMode(buttonPin, INPUT);	Reads signal from the button
digitalRead(buttonPin);	Checks if the button is pressed (HIGH) or not (LOW)
digitalWrite(ledPin, HIGH);	Turns LED ON when button is pressed
digitalWrite(ledPin, LOW);	Turns LED OFF when button is released

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⚡ Working Principle

• The push button acts as a switch.
• When pressed, current flows from 5V → button → pin 7, signaling Arduino to light up the LED.
• When released, pin 7 goes LOW, and the LED turns OFF.

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🧪 Experiment Ideas

• Modify the code so the LED stays ON even after releasing the button (toggle effect).
• Use two buttons — one for turning ON, another for turning OFF.
• Add a buzzer along with LED for feedback.

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✅ Learning Outcome

After completing this project, you’ll understand:

• How to read digital inputs from a button.
• How to control outputs based on input signals.
• The concept of HIGH and LOW logic in Arduino.

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Would you like me to make a circuit diagram (with Arduino, button, LED, and resistor) for your exact pin setup (LED on D8, button on D7 → 5V)?