Intelligent Traffic Light Control System Using 8051 Microcontroller

Our project aims to Eliminate the delay on Roads by reducing Traffic on road automatically using Smart Systems. It determines traffic on each road by using sensors. Using that traffic information we can manage the signal time and handle the traffic on road. On each road we place IR sensors which detect the vehicle and give current traffic information on each road. The timing of signal is adjusted according to traffic level on each road. The road which has level more than other road then this road assign green signal and for others have red is assign. It also provides the additional functionality of release the emergency vehicle on its occurrence that means when emergency vehicle is seen. In our project we focus on optimization of traffic light controller in a city using IR sensor and developed system using microcontroller AT89s52. We present this paper because to reduce traffic jamming which results in long waiting times to turn signal green, loss of fuel and money. For national development it is necessary to reduce traffic congestion on the major roads.


Microcontroller AT89s52 Development Board:

The heart of the system is microcontroller AT89s52. This microcontroller fall under, 8051 microcontroller including chip ROM which is in form of flash memory. After some time flash memory can be erased which provide fast process. We are selecting this Microcontroller Development Board of AT89c52 because it is easy of programming, sufficient number of input output lines, manageable size of RAM and ROM and simple architecture. System program and application program are stored using RAM and ROM. The block diagram of ITLCS consists of the microcontroller, input switching matrix, Real Time Clock 1307, Clock circuit, Relay Driver ULN2003, LED interfacing circuit.

IR Sensor:

This IR sensor detects Vehicle and also detect the Emergency Vehicle. Thermal Radiation is emitted by all the objects in the Infrared Spectrum. The Infrared Sensor detects this type of radiation which is not visible to human eye.



  • Easy for interfacing
  • Readily available in market


The basic idea is to make use of IR LEDs to send the infrared waves to the object. Another IR diode of the same type is to be used to detect the reflected wave from the object. For example, when emergency vehicle come like ambulance, police etc is come which have already set sensor that time sensor detects this emergency vehicle and sender, receiver sensor send signals to each other. When IR receiver is used to infrared light, a voltage difference is produced. At less voltage which is produced can be hardly detected and therefore operational amplifiers are used to detect low voltages accurately. The signals generate from sensor will be applied to input switching circuit. These input signals which generate from sensors will be in the form of digital signals that indicate the presence or absence of a vehicle. These digital signals from each road will be given to the input port of microcontroller, where the microcontroller will determine the length of vehicle at each road and counts the length of each road and decide to on which road which signal is glow. This information is the input to microcontroller to determine the various timing signals where the ON and OFF time of the four junctions will be calculated by microcontroller, in order to keep the waiting time minimum and these signals will be applied to two relay drivers which consist of ULN2003.


Steps to handle system:

  • Log into System.
  • Select control type.
  • If Automatic mode select then go to step 4th else go to step 8.
  • If Automatic control activated.
  • Assign time period for green, yellow signal.
  • If emergency vehicle is over then go to step 4.
  • If rally come then go to step 8.
  • Manual control activated.
  • Assign time period for green, yellow signal according to that particular road.
  • If emergency over then go to step 4.

Expected Outcome

The Expected Outcome of our system is to solve congestion problem on junction without human in automatic mode and with human interaction in manual mode. Our system provides control on traffic using automatic and manual mode (for example if any rally comes then set manual mode by setting time). So even if any emergency vehicle is detected by sensor then give path to these vehicle and set traffic system as it is. So traffic problem is easily solved by using Intelligent Traffic Light Control System.

8051 Development Board

RoboMart Team