Microcontroller Based Vehicle Speed Control System

Published Date: 02 Nov 2017

Abstract–The goal of developing the system is to control the speed of vehicles and to avoid accidents. Using the system we can control and monitor speed. If the speed goes beyond first limit then alarm is generated to notify the driver and after that if the speed again is increased to the given limit than the vehicle is automatically switched off for fixed time interval.

The developed system will take input from Hall Effect sensor in the form of pulses. Hall Effect sensor is already present in the wheelsof vehicle. Thus, using the pulses generated by Hall Effect sensor the speed of the vehicle can be determined. System uses GSM modem for communication i.e. to send message to the owner of vehicle on mobile phone. Message will be sent only if the speed reaches the maximum limit and thus aware the driver of that vehicle by generating alarm in the form of beep

Keywords-Real time system, embedded system, Vehicle speed controls, 8051microcontroller, GSM modem RS232, Hall Effect sensor.

INTRODUCTION

It is known that road accidents are increasing day by day. Most of these road accidents are caused because the vehicles are driven at high speeds. It is also caused if the places have sharp turnings and junctions exist [1]. Running the vehicles even at those places is the main cause for the accidents. Reduction of number of such accidents is the prime step needed to be taken. Many systems have been developed to prevent these road accidents .One of them is CC i.e. Cruise control system [2] that is capable of maintaining speed defined by the driver and its another version ACC i.e. Adaptive Cruise Control [3] that keeps the vehicle at safer distance from the preceding vehicle. But these systems have no capability to detect the curved roads where the speeds of the automobiles have to be lowered to avoid the accidents. Later curve warning systems(CWS) have been developed to detect the curved roads by using Global Positioning System (GPS) and the digital maps obtained from the Geographical Information Systems (GIS) [4] to assess threat levels for driver if approaching the curved road quickly. But these maps need to be updated regularly and are not useful if there are unexpected road. In the current existing system, manually operated systems are used ,for example in public transport buses, a rod is welded below the accelerator and in some cases speed lockers are used in gear box so that the buses cannot cross certain limit. Speed Controller system is developed for Fiat Punto which is a four wheeler, but this system is not available for Two-wheelers. So we are developing a system which controls speed of the vehicle and sends an alert message to the owner, that vehicle has crossed maximum limit. The model thus developed will deal totally to control the speed of the vehicle. The model main aim is to develop a speedometer. And using this speedometer detects the speed of the vehicle by sensing the pulses generated by Hall Effect sensor present in the tyre of the vehicle. After determining the speed, if the speed goes beyond the fixed limit then alerts the driver of vehicle by an alarm and also using the GSM modem to send message to the owner of that vehicle. The alarm is generated for the first fixed speed limit, and if the speed limit is further exceeded to the maximum limits then slowing down the speed of the vehicle for fixed time.

2. HARDWARE REQUIRED

Figure1. Block diagram of the system

So, following are the hardware requirement for the system to be developed.

2.1 Microcontroller (89s52)

Figure2. Microcontroller 89s52

Microcontroller used is 89s52. It has 40 Pin I/O (P0.0-0.7 , P1.0-1.7 , P2.0-2.7 , P3.0-3.7). RESET Pin NO. 9. (Active High)CRYSTAL Pins AT 18 -19 Pin. Serial half duplex port at (P3.0 (RX.) – P3.1 (TX.)). Interrupts at (P3.2 (INT0)- P3.3 (INT1))2 and Timers at (P3.4 (T0)- P3.5 (T1))

2.2Hall Effect sensor

Figure3. Hall Effect sensor

The UGN3503LT Hall-effect sensors accurately track extremely small changes in magnetic flux density—changes generally too small to operate Hall- effect switches. HallEffect sensor is used to produce pulses.

2.3GSM modem

Figure4. GSM modem

The GSM modem used in the project is to send message. These GSM modem can accept any GSM network operator SIM card .Using these modem, we can use rs232 port to communicate.Applications like SMS Control,data transfer, remote control and loggingcan be developed easily..It can be used to send and receive SMS.

2.3Liquid Crystal Display

Figure4. Liquid Crystal Display

LCD is used in a project to visualize the output of the application. We have used 16x2 LCD which indicates 16 columns and 2 rows. So, we can write 16 characters in each line. So, total 32 characters we can display on 16x2 LCD.

LCD can also used in a project to check the output of different modules interfaced with the microcontroller. Thus LCD plays a vital role in a project to see the output and to debug the system module wise in case of system failure in order to rectify the problem.

Figure5. Power Supply

The basic step in the designing of any system is to design the power supply required for that system. The steps involved in the designing of the power supply are as follows.

1) Determine the total current that the system sinks FROM the supply.

2) Determine the voltage rating required for the different components.

3. CONCEPT OF VEHICLE SPEED CONTROL

Figure6. Interfacing of Microcontroller with GSM modem

In general, the speed of the vehicle is varied according to the accelerator pedal position. The concept used in developing the model is detecting the speed of the vehicle using microcontroller and controlling the speed by slowing down the speed and also generating alarm and sending message. The figure above shows the block diagram of model. It consists of microcontroller 8051, Hall Effect sensor, GSM modem, speedometer and alarm for making alarm sound. The speed of the vehicle is configurable. Device will operate using vehicle’s battery. Message will also be configurable.

The procedure to implement is, first we have to connect the device to the vehicle in such a way that two wires are connected to the battery and two wires to the speedometer. Set the speed limit. Drive the vehicle. Now, the microcontroller will sense the pulses from the Hall Effect sensor and check the speed limit.

Microcontroller is used has a hardware interface. It is used to take the input from Hall Effect sensor and used to determine speed of vehicle. This Hall Effect sensor is present in the wheels of a vehicle. The pulses produced by the Hall Effect sensor are sensed by microcontroller. Thus, microcontroller takes pulses as input and thus the speed produced is the output

(which is the actual speed of the vehicle).Working of hall effect sensor is that it generates a pulse each time the magnet comes near it, once every revolution of the shaft. Then the pulses are fed to counter, and count the number of pulses in specific time interval.eg 50 counted pulses in one sec time interval means the shaft is turning at :50rev/sec=3000rev/minute. Now the micro controller checks the speed of the vehicle. If the speed limit is exceeding then by using GSM modem, the message is send to the owner of the vehicle. So, GSM modem is used for communication and aware the owner about the speed. Alarm is also interfaced with microcontroller which is used to produce sound if the speed exceeds the fixed limit.

Figure7. RS232 Connections

The above figure represents the internal connection of pc to the system for configuration of speed. Sunrom 3 core cable is used for connection

4. ACTIVITY DIAGRAM

The figure below represents the activity diagram of system. It shows the process of flow of activities. Initially, we have to initialize the setup i.e. start the vehicle. After the vehicle starts, with the help of Hall Effect sensor record the speed of the vehicle on speedometer. In the beginning the speed limits are set. So, while driving if the speed passed the given speed limit then a message is sent to owner of vehicle using GSM modem and also alarm is turned ON. And after alerting the driver through alarm, if the speed is exceeded across the second fixed limit then automatically the switch is turn off for 30 sec. So that the speed is reduced. After that the switch is turned ON.

Figure8. Activity Diagram

5. CONCLUSIONS

In this paper we presented a new design to control thespeed of vehicles. A real time system is built using microcontroller 8051.. The microcontroller is interfaced with Hall Effect sensor to impose restriction on speed. By implementing alarm system a good safety measurement has been taken. Also the GSM modem is used for communication purpose i.e. to send message on mobile phones. This paper also concludes that system can impose restriction on speed, due to which safe driving is possible. It also provides high end security as speed is controlled. Rate of accidents can be minimized. Alert message is send to Owner and thus provides communication.