DENSITY BASED TRAFFIC LIGHT TIMING CONTROL Project Title DENSITY BASED TRAFFIC LIGHT TIMING CONTROL Under the Guidance of Submitted by

ABSTARCT The aim of the project is to solve traffic congestion, To solve the problem, we have designed a framework for a dynamic and automatic traffic light control system and developed a simulation model with codes to help building the system on hardware. It is possible to propose dynamic time-based coordination schemes where the green signal time of the traffic lights is assigned based on the present conditions of traffic. This is achieved by using 3 pair of IR sensors (Transmitter and Receiver) across the road to monitor a particular length / zone while vehicles on the same zone block the IR light falling on the IR receiver to assume low traffic density. As there are 3 zones only, it is immaterial if vehicles are parked side by side. As it crosses the zone, the green time automatically changes as programmed

PROJECT BLOCK DIAGRAM

HARDWARE COMPONENTS PIC MICROCONTROLLER (PIC16F877A) IR LED PHOTODIODE POWER SUPPLY BLOCK PIC MICROCONTROLLER (PIC16F877A) IR LED PHOTODIODE BC547 LED 1N4007 RESISTORS CAPACITORS

POWER SUPPLY Bridge rectifier 5v Regulator 230 V AC 50 Hz 5V DC Filter(470µf) 12V step down transformer

Pic Microcontroller(PIC16F877A) High-Performance RISC CPU: • Only 35 single-word instructions. • All single-cycle instructions except for program branches, which are two cycle. • Operating speed: DC – 20 MHz clock input DC – 200 ns instruction cycle • Up to 8K x 14 words of Flash Program Memory, Up to 368 x 8 bytes of Data Memory (RAM), Up to 256 x 8 bytes of EEPROM Data Memory. • Pin out compatible to other 28-pin or 40/44-pin, PIC16CXXX and PIC16FXXX microcontrollers.

Special Microcontroller Features: • 100,000 erase/write cycle Enhanced Flash program memory typical. • 1,000,000 erase/write cycle Data EEPROM memory typical. • Data EEPROM Retention > 40 years. • Self-reprogrammable under software control. • In-Circuit Serial Programming™ (ICSP™) via two pins. • Single-supply 5V In-Circuit Serial Programming. •Watchdog Timer (WDT) with its own on-chip RC oscillator for reliable operation. • Programmable code protection. • Power saving Sleep mode. • Selectable oscillator options. • In-Circuit Debug (ICD) via two pins.

Peripheral Features: • Timer0: 8-bit timer/counter with 8-bit prescaler. • Timer1: 16-bit timer/counter with prescaler, can be incremented during Sleep via external crystal/clock. • Timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler. • Two Capture, Compare, PWM modules - Capture is 16-bit, max. resolution is 12.5 ns - Compare is 16-bit, max. resolution is 200 ns - PWM max resolution is 10-bit • Synchronous Serial Port (SSP) with SPI™ (Master mode) and I2C™ (Master/Slave). • Universal Synchronous Asynchronous Receiver Transmitter (USART/SCI) with 9-bit address detection. • Parallel Slave Port (PSP) – 8 bits wide with external RD, WR and CS controls (40/44-pin only). • Brown-out detection circuitry for Brown-out Reset (BOR).

PIN DIAGRAM OF PIC16F877

IR LED An IR LED, also known as IR transmitter, is a special purpose LED that transmits infrared rays in the range of 760 nm wavelength. Such LEDs are usually made of gallium arsenide or aluminum gallium arsenide. They, along with IR receivers, are commonly used as sensors. The appearance is same as a common LED. Since the human eye cannot see the infrared radiations, it is not possible for a person to identify whether the IR LED is working or not, unlike a common LED. To overcome this problem, the camera on a cell phone can be used. The camera can show us the IR rays being emanated from the IR LED in a circuit.

PHOTO DIODE A photodiode is a type of photo detector capable of converting light into either current or voltage, depending upon the mode of operation. Photodiodes are similar to regular semiconductor diodes except that they may be either exposed (to detect vacuum UV or X-rays) or packaged with a window or optical fibred connection to allow light to reach the sensitive part of the device.

BC547 The BC547 transistor is an NPN Epitaxial Silicon Transistor. The BC547 transistor is a general-purpose transistor in small plastic packages. It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general-purpose transistors. Whenever base is high, then current starts flowing through base and emitter and after that only current will pass from collector to emitter  

Working of Project The project uses the IR interruption concept for generating logic states to the input of the MC. To achieve the same a number of IR diodes are used facings photodiodes. While the IR light falls on the photodiode the resistance of the photodiode falls increasing the bias voltage Logic high sensed by the MC input changes the green ON time to a higher value for allowing more vehicles to pass through. After sometime in case any other way gets more logic high, the sequential timing gets automatically increased for that way. Based on the IR interruption the green ON time increases, thus more the vehicle longer will be the green signal time. Thus dynamic time control is achieved based on the traffic density.

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