Auto Speed Controller of Automobiles



The project is designed to control the traffic on the highways.

In this project lane system of roads is also considered. In this project we have taken three lanes as an example.

First lane is of speed limit 40KmPh, second lane is of 60KmPh and third one is of 80KmPh.

All the three lanes are equipped with IR receivers which transmits the details of the lane.

For this project, increase in voltage is considered as increase in speed.

All the three receivers are connected with a microcontroller, PIC16F73, since this is an analog to digital converter. This microcontroller keeps the record of the lanes.

On each vehicle a transmitter is connected with different voltage supply, say for 40kmph, it is 4V, and so on.

Whenever any vehicle passes over the RX of the controller unit, it transmits its details to the controller, which checks about the limit of the vehicle on that particular lane.

If the limit is correct and prominent to that of the described one, than its ok but if it is different than controller displays a message on the screen of the vehicle that ‘you are exceeding the limit of speed please change lane’. Simultaneously it transmits the data to the control tower too, where computer keeps an eye on the entire highway.

If the vehicle does not change its lane after receiving the warning three times than, control tower sends an instruction to the patrolling police that this particular vehicle is exceeding the limit and is not changing the lane too.

After which police take an appropriate action against the driver


Working of the entire mechanism is illustrated with the help of following steps:

  1. Each lane has a line of IR LED’s, connected with an IR Encoder IC, which transmits the lane information continuously to the passing vehicles on the highway.
  2. Each Encoder has a particular address bit connected with the ground for transferring this information.
  3. The Transmitted information is received at the IR RX section of the Vehicle which is then connected with the IR Decoder IC.
  4. This IC will transfer the code to the PIC, microcontroller, which has been programmed to read the track or lane information.
  5. After reading the lane information microcontroller transfer a message to the LCD, n starts reading the speed of the vehicle.
  6. Speed is calculated on the basis of current produced on the motor connected on the vehicle.
  7. This speed is also displayed on the LCD; with this it also matches the speed with the displayed speed limit.
  8. If this speed exceeds the limit, LCD displays a message as ‘you have exceeded the limit one Time’.
  9. After three such messages PIC transmits a data bit to the server location through an encoder IC and an IR TX.
  10. On the server location a microcontroller is connected with a Decoder IC and an IR RX.
  11. This microcontroller displays the message on LCD as ‘vehicle one has exceeded the limit’.


Construction of the project is illustrated by the following steps:

  1. Three lanes with different speed limits are constructed; speed limit is decided and controlled by an encoder IC AO20E, with IR LED.
  2. For transmitting the data bits IR LED are fixed at the regular distances on each lane.
  3. An IR RX module is connected on the vehicle’s base, with one decoder IC AO20D and a PIC16F73 Microcontroller. We used a PIC because of its inbuilt Analog to digital converter.
  4. Similarly another Encoder IC is connected at one of the other port of the PIC to transmit the data to the server mainframe.
  5. A LCD is connected to display the messages of the corresponding changes.
  6. This entire system is mounted on the vehicle itself.
  7. On the sever end a simple decoder IC is connected to the Microcontroller 89C2051, with a LCD and a buzzer.


  • higher safety
  • speed control
  • avoid accidents
  • give us position of real traffic
  • etc


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