11-04-2012, 10:42 AM
AUTOMATIC CAR PARKING SYSTEM USING 89C51 MICROCONTROLLER
AUTOMATIC CAR PARKING SYSTEM USING 89C51 MICROCONTROLLER.doc (Size: 610.5 KB / Downloads: 478)
The Project Automatic Car Parking System using 89C51 Microcontroller is an interesting project which uses 89C51 microcontroller as its brain. The project is designed for car parking.
The aim of this project is to atomize the car park for allowing the cars into the park. LCD is provided to display the information about the total number of cars that can be parked and the place free for parking. Two IR TX – RX pairs are used in this project to identify the entry or exit of the cars into/out of park. These two IR TX – RX pairs are arranged either side of the gate. The TX and RX are arranged face to face across the road so that the RX should get IR signal continuously.
Whenever the mains are switched on, the LCD displays the message “parking space for 10 vehicles”. The number indicates the maximum capacity of park in this project. Whenever a car comes in front of the gate, the IR signal gets disturbed and the microcontroller will open the gate by rotating the stepper motor. The gate will be closed only after the car leaves the second IR pair since the microcontroller should know whether the car left the gate or not. Now the microcontroller decrements the value of the count and displays it on LCD. In this way, the microcontroller decrements the count whenever the car leaves the park and displays it on LCD.
If the count reaches ‘0’, i.e. if the park is completely filled, the microcontroller will display “NO SPACE FOR PARKING” on LCD. And now if any vehicle tries to enter the park, the gate will not be opened since there is no space. If any vehicle leaves the park, the controller will increment the count and allows the other vehicles for parking.
This project uses regulated 5V, 500mA power supply. Unregulated 12V DC is used for relay. 7805 three terminal voltage regulator is used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac out put of secondary of 230/12V step down transformer.
DESCRIPTION
POWER SUPPLY:
The input to the circuit is applied from the regulated power supply. The a.c. input i.e., 230V from the mains supply is step down by the transformer to 12V and is fed to a rectifier. The output obtained from the rectifier is a pulsating d.c voltage. So in order to get a pure d.c voltage, the output voltage from the rectifier is fed to a filter to remove any a.c components present even after rectification. Now, this voltage is given to a voltage regulator to obtain a pure constant dc voltage.
Transformer:
Usually, DC voltages are required to operate various electronic equipment and these voltages are 5V, 9V or 12V. But these voltages cannot be obtained directly. Thus the a.c input available at the mains supply i.e., 230V is to be brought down to the required voltage level. This is done by a transformer. Thus, a step down transformer is employed to decrease the voltage to a required level.
Rectifier:
The output from the transformer is fed to the rectifier. It converts A.C. into pulsating D.C. The rectifier may be a half wave or a full wave rectifier. In this project, a bridge rectifier is used because of its merits like good stability and full wave rectification.
Filter:
Capacitive filter is used in this project. It removes the ripples from the output of rectifier and smoothens the D.C. Output received from this filter is constant until the mains voltage and load is maintained constant. However, if either of the two is varied, D.C. voltage received at this point changes. Therefore a regulator is applied at the output stage.
Voltage regulator:
As the name itself implies, it regulates the input applied to it. A voltage regulator is an electrical regulator designed to automatically maintain a constant voltage level. In this project, power supply of 5V and 12V are required. In order to obtain these voltage levels, 7805 and 7812 voltage regulators are to be used. The first number 78 represents positive supply and the numbers 05, 12 represent the required output voltage levels.
MICROCONTROLLERS:
Microprocessors and microcontrollers are widely used in embedded systems products. Microcontroller is a programmable device. A microcontroller has a CPU in addition to a fixed amount of RAM, ROM, I/O ports and a timer embedded all on a single chip. The fixed amount of on-chip ROM, RAM and number of I/O ports in microcontrollers makes them ideal for many applications in which cost and space are critical.
The Intel 8051 is a Harvard architecture, single chip microcontroller (µC) which was developed by Intel in 1980 for use in embedded systems. It was popular in the 1980s and early 1990s, but today it has largely been superseded by a vast range of enhanced devices with 8051-compatible processor cores that are manufactured by more than 20 independent manufacturers including Atmel, Infineon Technologies and Maxim Integrated Products.
8051 is an 8-bit processor, meaning that the CPU can work on only 8 bits of data at a time. Data larger than 8 bits has to be broken into 8-bit pieces to be processed by the CPU. 8051 is available in different memory types such as UV-EPROM, Flash and NV-RAM.
The microcontroller used in this project is AT89C51. Atmel Corporation introduced this 89C51 microcontroller. This microcontroller belongs to 8051 family. This microcontroller had 128 bytes of RAM, 4K bytes of on-chip ROM, two timers, one serial port and four ports (each 8-bits wide) all on a single chip. AT89C51 is Flash type 8051.
The present project is implemented on Keil Uvision. In order to program the device, Proload tool has been used to burn the program onto the microcontroller.
The features, pin description of the microcontroller and the software tools used are discussed in the following sections.