Density Based Traffic Signal with Remote Override in Emergency Project Title Density Based Traffic Signal with Remote Override in Emergency 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 MICROCONTROLLER (AT89S52/AT89C51) IR LED POWER SUPPLY BLOCK MICROCONTROLLER (AT89S52/AT89C51) 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

It is a smaller computer Has on-chip RAM, ROM, I/O ports... MICROCONTROLLER It is a smaller computer Has on-chip RAM, ROM, I/O ports... RAM ROM I/O Port Timer Serial COM Port Microcontroller CPU A single chip

INTERNAL STRUCTURE OF A MICRO CONTROLLER-AT89S52/51 CPU On-chip RAM On-chip ROM for program code 4 I/O Ports Timer 0 Serial Port OSC Interrupt Control External interrupts Timer 1 Timer/Counter Bus Control TxD RxD P0 P1 P2 P3 Address/Data Counter Inputs

Features of AT89S51/52 Compatible with MCS®-51 Products 8K Bytes of In-System Programmable (ISP) Flash Memory Endurance: 10,000 Write/Erase Cycles 4.0V to 5.5V Operating Range Fully Static Operation: 0 Hz to 33 MHz 256 x 8-bit Internal RAM 32 Programmable I/O Lines Three 16-bit Timer/Counters Eight Interrupt Sources Full Duplex UART Serial Channel Interrupt Recovery from Power-down Mode Watchdog Timer Dual Data Pointer

Pin Description

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   BC547

Schematic Diagram RX

Schematic Diagram TX

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.

RF transmitter connected at transmitter end with Sw1 to sw4 placed on the hand held unit are meant as to which direction the emergency vehicle is required to move. Thus based on the switch ,the corresponding LED glows to indicate the direction of override and the same is fed in form of 4 bit data to the HT12E the encoder IC that sends serially the data to the transmitter module. This data is received by the receiver as explained above to enable only one green traffic signal LED in a junction of 4 while all the rest 3 are kept in red. Thus the emergency vehicle gets green signal. After a preset time the junction returns to normal sequence time based traffic signal with density sensing as usual as explained earlier.

Soft ware Requirements Keil an ARM Company makes C compilers, macro assemblers, real- time kernels, debuggers, simulators, integrated environments, evaluation boards, and emulators for ARM7/ARM9/Cortex-M3, XC16x/C16x/ST10, 251, and 8051 MCU families. Compilers are programs used to convert a High Level Language to object code. Desktop compilers produce an output object code for the underlying microprocessor, but not for other microprocessors.

i.e the programs written in one of the HLL like ‘C’ will compile the code to run on the system for a particular processor like x86 (underlying microprocessor in the computer). For example compilers for Dos platform is different from the Compilers for Unix platform  So if one wants to define a compiler then compiler is a program that translates source code into object code.

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