Project 1.3.2: TWIN LIGHT

Description	This project shows how to control two LEDs using a push button with an Arduino Uno. When the button is pressed, both LEDs turn on at the same time. When the button is released, both LEDs turn off.
Use case	This project can be used as a simple signal system where two lights work together to show notifications or indicate someone's presence.

Components (Things You will need)

Building the circuit

Things Needed:

• Arduino Uno = 1
• Arduino USB cable = 1
• Resistor = 1
• Push button = 1
• LED = 2
• Red jumper wires = 1
• Black jumper wires = 1
• Yellow jumper wires = 1
• Blue jumper wires = 1

Mounting the component on the breadboard

Step 1: Place the two LEDs on the breadboard. The longer legs are the positive pins, while the shorter legs are the negative pins.

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Step 2: Connect the positive leg of the first LED to pin 9 on the Arduino through a 220Ω resistor.

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WIRING THE CIRCUIT

Things Needed:

• Red male-male-to-male jumper wires = 1
• Black male-to-male jumper wires = 1
• Yellow male-to-male jumper wires = 1
• Blue male-to-male jumper wires = 1
• White male-to-male jumper wires = 1
• Green male-to-male jumper wires = 1

Step 3: Connect the negative leg of the first LED to GND on the Arduino Uno.

Step 4: Connect the positive leg of the second LED to pin 7 on the Arduino through a 220Ω resistor.

Step 5: Connect the negative leg of the second LED to GND on the Arduino Uno.

Step 6: Place the push button on the breadboard.

Step 7: Connect one side of the push button to GND on the Arduino Uno.

Step 8: Connect the other side of the push button to pin 13 on the Arduino Uno.

Make sure to connect the Arduino USB blue cable to the Arduino board.

PROGRAMMING

Step 1: Open your Arduino IDE. See how to set up here: Getting Started.

Step 2: Type int ledPin1 = 9; as shown in the picture below.

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Step 3: Type const int LedPin2 = 7; as shown in the picture below.

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Step 4: Type int buttonPin = 13; as shown in the picture below.

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Step 5: Type int buttonState = 0; as shown in the picture below.

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Step 6: Inside the (void setup()) function, type pinMode (ledPin1, OUTPUT); as shown in the picture below.

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NB: pinMode will help the Arduino board to decide which port should be activated.

Step 7: Inside the (void setup()) Type pinMode (ledPin2, OUTPUT); as shown in the picture below.

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Step 8: Type pinMode (buttonPin, INPUT_PULLUP); as shown in the picture below.

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Step 9: Scroll down and click inside the void loop() function and Type buttonState = digitalRead (buttonPin); as shown in the picture below.

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Step 10: Type this conditional statement if (buttonState == LOW) { digitalWrite (LedPin1, HIGH); digitalWrite (ledPin2, HIGH); } as shown in the picture below.

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Step 11: Type else { digitalWrite (LedPin1, LOW); digitalWrite (ledPin2, LOW); } as shown in the picture below.

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Explanation

int ledPin1 = 9; stores the pin number for the first LED. int ledPin2 = 7; stores the pin number for the second LED. int buttonPin = 13; stores the push button pin number. int buttonState = 0; stores the current state of the push button. pinMode(ledPin1, OUTPUT); sets the first LED pin as an output pin. pinMode(ledPin2, OUTPUT); sets the second LED pin as an output pin. pinMode(buttonPin, INPUT_PULLUP); sets the push button pin as an input pin. digitalRead(buttonPin); reads the state of the push button. digitalWrite(ledPin1, HIGH); turns the first LED on. digitalWrite(ledPin2, HIGH); turns the second LED on. digitalWrite(ledPin1, LOW); turns the first LED off. digitalWrite(ledPin2, LOW); turns the second LED off.

CONCLUSION

This project helps learners understand how to control multiple LEDs using a push button with Arduino. It introduces input devices, output devices, and simple control logic in programming.