1.Introduction:

Automatic multistoried car parking system helps to minimize the car parking area. In the modern world, where parking-space has become a very big problem and in the era of miniaturization, it is become a very crucial necessity to avoid the wastage of space in modern, big companies and apartments etc. In places where more than 100 cars need to be parked, this system proves to be useful in reducing wastage of space. This Automatic Car Parking System enables the parking of vehicles, floor after floor and thus reducing the space used. Here any number of cars can be parked according to the requirement. This makes the system modernized and even a space-saving one. This idea is developed using 8051 Microcontroller. Here program is written according to this idea using 8051.

2. Basic idea:

A display is provided at the ground floor which is basically a counter that displays number of cars in each floor. It informs whether the floors are fully filled with the cars or is it having place in a particular floor or not. There is facility of lift to carry the car to up and down. Movement of Lift is controlled by stepper motor. An indicator with a green and red LED is kept in all the floors to indicate whether the lift is busy or is it ready to take the car up or down. If the red LED glows that means the lift is already engaged and the person has to wait for the green LED to glow. In this project we have provided three floors of a building for car parking. Maximum storage capacity of each floor is given as ten. Storage capacity can be changed according to the requirement.

Any one can enter to first or second floor. The third floor in this model is for VIP’s only. Therefore when VIP’s are to be entering they are expected to enter their password and they will be taken to the third reserved floor. The password will be of 4 digits. The processor checks for the password entered and if it is found to be wrong, a siren is heard. In this particular model 10 passwords are stored. So when a password is entered, the processor checks for it and it is compared with 10 passwords. It indicates whether it is the correct one or not.

When the car enters the lift, the LDR detects its presence and sends a signal to glow RED LED indicating that the lift is busy. It also sends a signal to motor which makes the motor to rotate. After RED LED glows the lift will take the person and the car up to the floor where the space for parking is available. (For VIP it will be the third floor). When the lift reaches the first floor, the processor compares  the filled amount to that of the already fed capacity of that floor, and if it finds that the first floor is fully filled , it goes to the second floor and thus the procedure stops here. As soon as a car is placed in a particular floor, the display counter at the ground floor increments as to indicate the floor capacity has decreased by one. After the lift places the car in a particular floor, it comes back to its normal position and that time, the motor that drives it , also stops. Now processor sends signal to glow GREEN LED indicating that lift is free.

When a person needs to come down from a particular floor to ground floor, he is expected to focus the headlight onto the LDR placed in that floor. Now sensor section sends signal to motor that the lift has to be send back to that particular floor and sends a signal to glow RED LED indicating that the lift is busy. As soon as the lift reaches that particular floor car should come inside the lift, the display counter at the ground floor decrements by one as to indicate the floor capacity has increased by one. Lift comes back to its normal position and that time, the motor that drives it, also stops. Now processor sends signal to glow GREEN LED indicating that lift is free.

If there no parking taking place, the processor carries out the job according to the following priority:-

1. It checks whether any password is entered.
2. It checks whether any car is entered to lift.
3. It checks whether any car headlight is pressed in front of  LDR placed in each floor.

It is like a round robin system.

3. Hardware description:

Introduction to 8051 Microcontroller:

The first task faced when learning to use a new computer is to become familiar with the capability of the machine. The features of the computer best learned by studying the internal hardware design, also called the architecture of the device, to determine the type, number, and size of the registers and other circuitry.

The hardware is manipulated by an accompanying set of program instructions, or software. One familiar with hardware and software, the system designer can then apply the microcontroller to the problems at hand. In this project we make use of microcontroller.

The 8051 microcontroller generic part number actually includes a whole family of microcontrollers that have numbers ranging from 8031 to 8751.The block diagram of the 8051 shows all of the features unique to microcontrollers:

1. Internal ROM and RAM
2. I/O ports with programmable pins
3. Timers and counters
4. Serial data communication

The block diagram also shows the usual CPU components program counter, ALU, working registers, and the clock circuits.

The 8051 architecture consists of these specific features:

1. 8 bit CPU with registers A and B
2. 16 bit PC &data pointer (DPTR)
3. 8 bit program status word (PSW)
4. 8 bit stack pointer(SP)
5. Internal ROM or EPROM (8751)of 0(8031)to 4k(8051)
6. Internal RAM of 128 bytes.
7. 4 register banks , each containing 8 registers
8. 80 bits of general purpose data memory
9. 32 input/output pins arranged as four 8 bit ports:P0-P3
10. Two 16 bit timer/counters:T0-T1
11. Two external and three internal interrupt sources
12. Oscillator and clock circuits

A pin out of the 8051 packaged in a 40 pin DIP is shown below.

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Vcc, Vss, and VEE:

While Vcc and Vss  provide  +5V and ground, respectively, VEE  is used for controlling LCD contrast.

RS – register select:

There are two very important registers inside the LCD. The RS pin is used for their selection as follows. If RS = 0, the instruction command code register is selected, allowing the user to send a command such as clear display, cursor at home, etc. If  RS = 1 the data register is selected, allowing the user to send data to be displayed on the LCD.

R/W – read/write:

R/W input allows the user to write information to the LCD or read information from it. R/W = 1 when reading; R/W =0 when writing.

E – enable:

The enable pin is used by the LCD to latch information presented to its data pins. When data is supplied to data pins, a high to low pulse must be applied to this pin in order for the LCD to latch in the data present at the data pins. This pulse must be a minimum of 450 ns wide.

D0 – D7:

The 8 bit data pins, D0 – D7, are used to send information to the LCD or read the contents of the LCD’s internal registers.

To display letters and numbers, we send ASCII codes for the letters A – Z, a – z, and numbers 0 – 9 to these pins while making RS = 1.

There are also instructions command codes that can be sent to the LCD to clear the display or force the cursor to the home position or blink the cursor. Table below lists the instruction command codes.

We also use RS = 0 to check the busy flag bit to see if the LCD is ready to receive information. The busy flag is D7 and can be read when R/W =1 and RS = 0, as follows: if R/W =1, RS =0. When D7 = 1(busy flag = 1), the LCD busy taking care of  internal operations and will not accept any new information. When D7 = 0, the LCD is ready to receive new information. Note: It is recommended to check the busy flag before writing any data to the LCD.

Example programs are given in the next page.

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A Brief Description:

This a simple project with efficient hacking prevention from Brute Force etc. The basic user lock is of 5 Digits and Master Lock is of 10 digits so its not easy for an intruder to break the lock unless you keep the code simple.

The input is taken from a 4×3 Keypad (please see the schematic for more information) and Display the user input on a 2×16 LCD. A pin is assigned as output for activating and deactivating the lock. For demonstration i have connected an LED to that pin.

From user side:
The user has two options either he/she can use its own 5 digit code or use the default 5 digit code. If user has to do setup his own code, then he has to enter “12345” and press ‘#’. After this.. controller will ask for 10 Digit master password which is preprogrammed in the controller. Entering master lock, user can enter the new 5 digit code for the lock and press ‘#’ to save it.

Using the Keypad:
Keypad has 12 keys (4×3) starting from 1,2,3,4,5,6,7,8,9,*,0,# (please see the schematic for layout). Numeric keys are used for entering numbers. ‘*’ is used as the Cancel key and ‘#’ is used as the Enter key.

Circuit Diagram:

Download File Information:

1. LCD.C – 4-Bit LCD Drivers
2. LCD.H – LCD function prototypes and other declerations
3. Lock.C – code for lock functioning
4. LOCK.H – lock function declarations
5. KEYPAD.C – Keypad drivers
6. KEYPAD.H – Function declarations
7. DELAY.C – Delay Functions
8. DELAY.H – Function Prototypes only
9. MAIN.C – Main function!
10. Digital Code Lock Schematic – PDF file of orcad schematic

Download the source codes by clicking here

By Ajay Bhargav
http://rickeyworld.info

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