Traffic Light Controlled with Arduino Nano

In this project, I created a simple traffic light system using an Arduino Nano and three LEDs (red, yellow, and green) controlled by a button. The system simulates a basic traffic light sequence, with the green light as the default. When the button is pressed, the green light flashes three times before transitioning to yellow for 2.3 seconds, then red for 5 seconds, and finally both red and yellow for 2 seconds before returning to green. This project is a fun and practical way to learn about controlling LEDs and button inputs with Arduino.

This Arduino code controls three LEDs (red, yellow, and green) based on the state of a button connected to pin 2. Here’s a breakdown of the program:

Setup Function (void setup()):

• pinMode(2, INPUT);
  • Configures pin 2 as an input to read the button state.
• pinMode(3, OUTPUT);
  • Configures pin 3 as an output to control the red LED.
• pinMode(4, OUTPUT);
  • Configures pin 4 as an output to control the yellow LED.
• pinMode(5, OUTPUT);
  • Configures pin 5 as an output to control the green LED.

This sets up the necessary pin modes for reading the button and controlling the LEDs.

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Loop Function (void loop()):

The loop() function continuously runs and performs actions based on the state of the button (pressed or not pressed).

1. Reading the Button State:
   • bool buttonState = digitalRead(2);
     • Reads the state of pin 2 (button). The value is stored in the variable buttonState.
     • If the button is pressed, the state will be LOW (because it’s connected to ground when pressed).
     • If the button is not pressed, the state will be HIGH.

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2. When Button is Pressed (buttonState == LOW):
   • If the button is pressed (reads LOW), the following sequence happens:

   a. Flashing the Green Light (3 Times):

   • The green light (pin 5) will flash ON and OFF three times in the loop.
     for (int i = 0; i < 4; i++) {
digitalWrite(5, HIGH); // Green ON
delay(700); // Wait for 700 ms
digitalWrite(5, LOW); // Green OFF
delay(700); // Wait for 700 ms
}

     • The for loop repeats this ON/OFF cycle 4 times. For each cycle:
       • Green LED turns ON, waits for 700 ms.
       • Green LED turns OFF, waits for another 700 ms.

   b. Yellow Light ON for 2.3 Seconds:

   • After the green light flashes, the yellow light (pin 4) turns on for 2.3 seconds:
     digitalWrite(4, HIGH); // Yellow ON
delay(2300); // Wait for 2.3 seconds
digitalWrite(4, LOW); // Yellow OFF


   c. Red Light ON for 5 Seconds:

   • Next, the red light (pin 3) turns on for 5 seconds:
     digitalWrite(3, HIGH); // Red ON
delay(5000); // Wait for 5 seconds
digitalWrite(3, LOW); // Red OFF


   d. Red and Yellow Lights ON Together for 2 Seconds:

   • Both the red and yellow lights turn on together for 2 seconds, before switching back to the green light:
     digitalWrite(3, HIGH); // Red ON
digitalWrite(4, HIGH); // Yellow ON
delay(2000); // Wait for 2 seconds
digitalWrite(3, LOW); // Red OFF
digitalWrite(4, LOW); // Yellow OFF


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3. When Button is Not Pressed (else):
   • If the button is not pressed, the green light (pin 5) stays ON:
     digitalWrite(3, LOW); // Red OFF
digitalWrite(4, LOW); // Yellow OFF
digitalWrite(5, HIGH); // Green ON

   • Red and yellow lights remain OFF.

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Summary of the Code’s Behavior:

• Default state (no button press): Green light is ON.
• Button pressed: The green light flashes three times, followed by the yellow light for 2.3 seconds, the red light for 5 seconds, and both red and yellow lights for 2 seconds. Then it returns to the green light.