31-07-2014, 11:04 AM
MICRO CONTROLLER BASED TRAFFIC LIGHT CONTROLLER
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ABSTRACT
Vehicular traffic at intersecting streets is typically controlled by traffic control lights.
The function of traffic lights requires sophisticated control and coordination to
ensure that traffic moves as smoothly and safely as possible.
In recent days electro-mechanical controllers are replaced by electronic circuits. The
accuracy & fault tolerant drive towards electronic circuits.
This project is developed to meet the requirements of solid state traffic light
controller by adopting microcontroller as the main controlling element, and led’s as the
indication of light. A micro controller is interfaced to led’s provide for centralized control
of the traffic signals. Microcontroller is programmed in such a way to adjust their timing
and phasing to meet changing traffic conditions. The circuit besides being reliable and
compact is also cost effective.
INTRODUCTION
congestion has been causing many critical problems and challenges in the major
and most populated cities. To travel to different places within the city is becoming more
difficult for the travelers in traffic. Due to these congestion problems, people lose time,
miss opportunities, and get frustrated. Traffic congestion directly impacts the
companies. Due to traffic congestions there is a loss in productivity from workers, trade
opportunities are lost, delivery gets delayed, and thereby the costs goes on increasing.
To solve these congestion problems, we have to build new facilities &
infrastructure but at the same time make it smart. The only disadvantage of making new
roads on facilities is that it makes the surroundings more congested. So for that reason
we need to change the system rather than making new infrastructure twice. Therefore
many countries are working to manage their existing transportation systems to improve
mobility, safety and traffic flows in order to reduce the demand of vehicle use.
The project uses simple Electronic components such as LED as TRAFFIC LIGHT
indicator and a MICROCONTROLLER for auto change of signal after a pre-specified
time interval.
Microcontroller AT89c51 is the brain of the project which initiates the traffic signal
at a junction. The led’s are automatically on and off by making the corresponding port
pin of the micro controller high. A seven segment display also connected to display the
timing of each signal. At a particular instant only one green light holds and other
TRANSFORMER
A transformer is a device which step-up (or) step-down the electrical quantities
according to the need. It adjusts the Ac level so that the appropriate Dc amplitude is
achieved. Its load handling capacity must be sufficient to supply the load and account
for the losses in the rectifier, filter and regulator. The turn’s ratio is determined by the
output level required relative to the ac input amplitude.
CONSTRUCTION
LEDs are usually built on an n-type substrate, with an electrode attached to the p-type
layer deposited on its surface. P-type substrates, while less common, occur as well. Many
commercial LEDs, especially GaN/InGaN, also use sapphire substrate. Most materials used for
LED production have very high refractive indices. Light extraction in LEDs is an important
aspect of LED production.
FUTURE SCOPE
This project can be enhanced in such away as to control automatically the
signals depending on the traffic density on the roads using sensors like IR
detector/receiver module extended with automatic turn off when no vehicles are
running on any side of the road which helps in power consumption saving.
This proximity detector using an infrared detector shown in fig.1 can be
used in various equipment like automatic door openers and burglar alarms. The
circuit primarily consists of an infrared transmitter and an infrared receiver. The
transmitter section consists of a 555 timer IC functioning in astable mode. It is
wired as shown in the fig. 2. The output from astable is fed to an infrared LED via
resistor R4, which limits its operating current. This circuit provides a frequency
output of 38 kHz at 50 per cent duty cycle, which is required for the infrared
detector/receiver module.
The receiver section comprises an infra