This document describes a traffic light control system that uses infrared sensors to detect vehicle traffic density and dynamically adjusts traffic light timing. It contains 3 zones of IR transmitter-receiver pairs that monitor vehicle presence. When vehicles block the IR light, the microcontroller detects lower traffic density and extends the green light time. The system is designed and simulated using codes to help build the hardware. It aims to reduce traffic congestion through time-based coordination of lights according to present traffic conditions.

1. TRAFFIC DENSITY SENSED
SIGNAL LIGHT SYSTEM
Submitted by:
Anky

2. The aim of the project is to solve traffic congestion, To solve the problem,
we have designed a framework for a traffic light sensed signal light control
system and developed a simulation model with codes to help building the
system on hardware. a
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.
ABSTARCT

3. PROJECT BLOCK DIAGRAM

4. HARDWARE COMPONENTS
POWER SUPPLY BLOCK
MICROCONTROLLER (AT89S52/AT89C51)
IR LED
PHOTODIODE
BC547
LED
1N4007
RESISTORS
CAPACITORS

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

6. 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

7. 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
Interrup
t
Control
External interrupts
Timer 1
Timer/Counter
Bus
Control
TxD RxDP0 P1 P2 P3
Address/Data
Counter
Inputs

8. 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

9. PIN DESCRIPTION

10. 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.

11. 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.

12. 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

13. 1N4007
Diodes are used to convert AC into DC these are used
as half wave rectifier or full wave rectifier. Three
points must he kept in mind while using any type of
diode.

14. LED
LEDs are semiconductor devices are made out of silicon
When current passes through the LED, it emits photons as a
byproduct. Normal light bulbs produce light by heating a metal
filament until its white hot
LEDs present many advantages over traditional light sources
including lower energy consumption, longer lifetime,
improved robustness, smaller size and faster switching

15. RESISTOR
 Resistor is a two terminal passive electrical component that
implements electrical resistance as a circuit element.
 Resistors limits or regulate the flow of electrical current in an
electronic circuit.
 Resistors are available in a range of different resistance values
which are used as per the requirement.

16. CAPACITOR
 capacitor is a two terminal passive electrical component used
to store the electrical energy electrostatically in an electrical
field
 Capacitors are two types electrolytic and ceramic.
 Ceramic capacitors are unpolarized. These capacitors have
negligible internal inductance or resistance.
 Electrolytic capacitors are polarized and if connected
backwards are likely to explode.

17. 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.

18. 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.

19.  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.