Traffic Light Control System Using ATmega328P

Table of Contents

• Project Overview
• Project Objectives
• Prerequisites
• Project Steps
  • 1. Set Up the Circuit
  • 2. Configure the Microcontroller
  • 3. Write and Upload Code
  • 4. Test the Traffic Light System
  • 5. Enable Maintenance Mode
  • 6. Document and Submit
• Expected Deliverables
• Getting Started
• License
• Contact

Project Overview

This project simulates a basic traffic light system using an ATmega328P microcontroller. The system uses three LEDs (red, yellow, and green), with each light turning on sequentially every 3 seconds. It also includes a maintenance switch to turn off the entire system when needed.

The project is ideal for beginners in embedded systems and microcontroller programming, offering real-world traffic system behavior in a simple and understandable form.

Project Objectives

Simulate a real-world traffic light system using ATmega328P.

Use a physical switch to toggle the system for maintenance purposes.

Ensure only one LED is on at a time for accurate simulation.

Practice programming in embedded C using AVR-GCC or Atmel Studio.

Prerequisites

ATmega328P microcontroller

Basic knowledge of C programming for microcontrollers

Breadboard and jumper wires

3x LEDs (Red, Yellow, Green)

3x 100Ω resistors

1x Pushbutton switch

5V power supply or USBasp programmer

(Optional) Proteus simulation software

Project Steps

1. Set Up the Circuit

Connect:

PB2 → Red LED (with resistor)

PB3 → Yellow LED (with resistor)

PB4 → Green LED (with resistor)

PD2 → Pushbutton switch (with pull-up)

Use a pull-up resistor or enable internal pull-up via software.

2. Configure the Microcontroller

Set PB2, PB3, PB4 as output pins for LEDs.

Set PD2 as input pin with internal pull-up for the maintenance switch.

3. Write and Upload Code

c Copy Edit #include <avr/io.h> #include <util/delay.h> #define F_CPU 1000000UL

int main(void) { DDRB |= (1<<PB2) | (1<<PB3) | (1<<PB4); // LEDs as output DDRD &= ~(1<<PD2); // Switch as input PORTD |= (1<<PD2); // Enable pull-up on PD2

while (1)
{
    if (PIND & (1<<PD2))
    {
        PORTB = (1<<PB2); // RED
        _delay_ms(3000);
        PORTB = (1<<PB3); // YELLOW
        _delay_ms(3000);
        PORTB = (1<<PB4); // GREEN
        _delay_ms(3000);
    }
    else
    {
        PORTB &= ~((1<<PB2) | (1<<PB3) | (1<<PB4)); // All OFF
    }
}

}

4. Test the Traffic Light System

Power on the circuit.

LEDs should:

Red → 3s

Yellow → 3s

Green → 3s

Repeat

5. Enable Maintenance Mode

Press the switch connected to PD2.

All LEDs should turn off immediately.

Releasing the switch resumes normal operation.

6. Document and Submit

Include:

Schematic diagram (PNG or Proteus file)

Code file (main.c)

Explanation of system behavior

Screenshots (if simulated)

Expected Deliverables

Fully working traffic light system on hardware or simulation

Source code with comments

Circuit diagram (Proteus or drawn)

Optional: short video demo of the working project

Getting Started

To get started, ensure you have:

AVR-GCC or Atmel Studio installed

A way to flash code to ATmega328P (e.g., USBasp)

Proteus for simulation (optional)

Clone or download the repository and upload main.c to your microcontroller.

License

This project is licensed under the MIT License — feel free to use, modify, and share it!

Contact

For questions or collaboration opportunities, reach out:

📧 Email: thato6216@gmail.com 🔗 LinkedIn: https://www.linkedin.com/in/thatomaelane/