Introduction

This documentation provides an overview of a Traffic Light Control System implemented using an 8051 microcontroller. The system is designed to control a set of traffic lights and pedestrian lights at an intersection. It also includes a feature to adjust the intensity of streetlights based on the ambient light level sensed by a Light Dependent Resistor (LDR).

Schematic Diagram

Hardware Components

The project makes use of several essential hardware components to ensure its functionality. These components include:

• 8051 Microcontroller Development Board: This development board acts as the brain of the project, providing the necessary processing power and control over various aspects of the system.
• AT89S52 Microcontroller: The AT89S52 microcontroller is a key component that works in conjunction with the development board to execute commands and facilitate communication between different parts of the project.
• 10mm LEDs for Traffic Lights & Pedestrian Signals: To provide clear and visible indications for traffic lights and pedestrian signals, 10mm LEDs are integrated into the project. These LEDs emit bright and vibrant light, ensuring that the signals are easily visible to both drivers and pedestrians.
• Light Dependent Resistor (LDR): The inclusion of a light-dependent resistor in the project allows it to adapt and respond to changes in ambient light conditions. This enables the system to adjust the intensity of the LEDs based on the surrounding environment, ensuring optimal visibility and energy efficiency.
• Resistors: Resistors play a crucial role in regulating the flow of electrical current within the project. By carefully selecting and incorporating resistors of appropriate values, the system achieves the desired functionality and prevents any potential damage to the components.
• Jumper Cables: Jumper cables serve as the physical connections that link different components together, ensuring a seamless flow of data and power throughout the project. These cables provide flexibility and ease of assembly, allowing for efficient and reliable connections between the various hardware components.

By utilizing these carefully selected hardware components, the project is able to function effectively and deliver the desired results in a reliable and efficient manner.

Pin Connections

LEDs for Traffic Lights

LEDs for Pedestrian Signals

Light Sensor and Output

Code Structure

#include <reg51.h>	// Standard 8051 defines

sbit T1_R = P1^2;
sbit T1_Y = P1^1;
sbit T1_G = P1^0;

sbit T2_R = P1^5;
sbit T2_Y = P1^4;
sbit T2_G = P1^3;

sbit T3_R = P3^0;
sbit T3_Y = P1^7;
sbit T3_G = P1^6;

sbit T4_R = P3^3;
sbit T4_Y = P3^2;
sbit T4_G = P3^1;

sbit T5_R = P3^5;
sbit T5_G = P3^4;

sbit P1_R = P3^6;
sbit P1_G = P3^7;

sbit P2_R = P0^0;
sbit P2_G = P0^1;

sbit LDR = P0^2;
sbit LED = P0^3;
// Define Signal pins

// Initialize functions
void delay(unsigned int);
void streetlight();

void main()
{	
	// Initialize traffic light states
  T1_R = T2_R = T3_R = T4_R = T5_R = 0;
  T1_Y = T2_Y = T3_Y = T4_Y = 0;
  T1_G = T2_G = T3_G = T4_G = T5_G = 0;
	P1_R = P2_R = 0;
	P1_G = P2_G = 0;
  delay(1000);
	T1_R = T2_R = T3_R = T4_R = T5_R = 0;
  T1_Y = T2_Y = T3_Y = T4_Y = 1;
  T1_G = T2_G = T3_G = T4_G = T5_G = 1;
	P1_R = P2_R = 1;
	P1_G = P2_G = 0;
	delay(1000);
	while(1)
		{
			T1_R = T5_R = P1_G = 1;
			T1_G = T5_G = P1_R = 0;
			streetlight();
			delay(5000);
			T1_G = 1;
			T1_Y = 0;
			streetlight();
			delay(3000);
			T1_Y = 1;
			T5_G = P1_R = 1;
			T1_R = T5_R = P1_G = 0;
			
			T2_R = 1;
			T2_G = 0;
			streetlight();
			delay(5000);
			T2_G = 1;
			T2_Y = 0;
			streetlight();
			delay(3000);
			T2_Y = 1;
			T2_R = 0;
			
			T3_R = 1;
			T3_G = 0;
			streetlight();
			delay(5000);
			T3_G = 1;
			T3_Y = 0;
			streetlight();
			delay(3000);
			T3_Y = 1;
			T3_R = 0;
		
			T4_R = P2_G = 1;
			T4_G = P2_R = 0;
			streetlight();
			delay(5000);
			T4_G = 1;
			T4_Y = 0;
			streetlight();
			delay(3000);
			T4_Y = P2_R = 1;
			T4_R = P2_G = 0;
		}
}

void delay(unsigned int a)
{
	unsigned int i,j;
	for(i=0;i<a;i++)
	{
		for(j=0;j<1275;j++)
		{
			streetlight();
		}
	}
}

void streetlight()
{
	if (LDR == 0)
	{
		LED = 0;
	}
	else
	{
		LED = 1;
	}
}

Header Files