To get started with RFID-based automatic vehicle parking system, the vehicle owner has to first register the vehicle with the parking owner and get the RFID tag. When the car has to be parked, the RFID tag is placed near the RFID reader, which is installed near the entry gate of the parking lot. As soon as the RFID tag is read by the reader, the system automatically deducts the specified amount from the RFID tag and the entry gate boomer opens to allow the car inside the parking area. At the same time, the parking counter increments by one. Similarly, the door is opened at the exit gate and the parking counter decremented.
The system also offers the facility to recharge the amount for each RFID tag. No manual processing is involved. In addition, the system provides security.
Connector CON1 ( See component layout for pcb), diodes D1 through D4, capacitor C1, and voltage regulator ICs 7805 (IC1) and 7812 (IC2) form the power supply section of the automatic vehicle parking system. CON1 is a three-pin connector that provides 15V AC or DC power supply to the circuit. In case of 15V AC, diodes D1 through D4 form a bridge rectifier to rectify the AC supply. Capacitor C1 filters out the ripples from the rectified output. ICs 7805 and 7812 provide regulated +5V and +12V, respectively, to the circuit. +5V is used to operate the microcontroller, LCD, RFID and IR sensor circuit and +12V operates the motor.
H-bridge DC motor driver L293D (IC5) operates the DC motors to open the door or barrier for entry into and exit from the parking lot. Two high-current motor drivers can be used in place of L293D and 12V DC motors to control the entry and exit gates, respectively.
Dual-operational amplifier LM358 (IC4) is used as a voltage comparator to compare the output of the IR sensors with a fixed threshold voltage in order to know whether the IR beam is interrupted or not.
Two IR transmitter-receiver pairs are used. The IR LEDs are connected in forward-biased condition to the +5V power supply through 220-ohm resistors. These emit IR light, which is interrupted when an object comes into its way to the IR receiver. The IR receiving photodiodes are connected in reverse-biased condition to +5V power supply through 1-mega-ohm resistors. When the IR light falls on the photodiodes, their resistance changes and so does their output. This output is compared with a fixed voltage to give a digital output to the microcontroller in order to judge the entry and exit of the vehicles.
LCD display. LCD1 is a two-line, 16-character, alpha-numeric liquid crystal display. Data lines D0 through D7 of the LCD are connected to port 2 of AT89S52 (IC3). Reset (pin no. 4 of LCD) and enable (pin no. 6 of LCD) control lines are connected to port pins pin no. 16 and pin no. 17 of microcontroller, respectively. Control lines control data flow from the microcontroller to LCD.
When power is switched on, LED1 glows to indicate the presence of power in the circuit and LED2 glows to indicate the presence of RFID reader. Simultaneously, the ‘Automatic RFID Car Parking’ message is displayed on LCD1 along with a short beep from piezobuzzer PZ1. Transistor BC547 drives the buzzer.
When a car crosses the IR LED1- IR D1 pair installed at the entry gate, the gate boomer does not open until an RFID tag is placed near the RFID reader. After the tag is placed near the reader, the gate boomer opens for three seconds and closes automatically. If the initial recharge amount was Rs 900, the LCD display shows ‘Vehicle1 Amount’ in the first line and ‘Deducted 100’ in the second line, followed by ‘Balance Amount’ in the first line and ‘800’ in the second line. It is then followed by display of ‘Number of Cars’ in the first line and ‘001’ in the second line. If the parking lot is full, the message “Parking is Full, Sorry for Inconvenience” is displayed on LCD.
When a car leaves the parking area and crosses the IR beam between IR LED2 and IR D2 at the exit gate, the vehicle count decreases by one. The LCD shows the number of cars in the parking lot along with “Thanks for Visiting” message.
Burn the hex code into the AT89S52 microcontroller using a suitable programmer and then mount the microcontroller on the PCB. Install IR LED1-IR D1 pair at the entry gate such that these face each other. Similarly, install IR LED2-IR D2 pair at the exit gate.
For testing, switch on the circuit, interrupt the infrared beam between IR LED1 and IR D1 with your hand or some other opaque object and then remove it, and place the tag near the reader. The LCD should show the message as described earlier in ‘How this vehicle parking system works’ section. An amount of Rs 100 should be deducted for every interruption of the IR beam. The card can be recharged by pressing the pushbutton switches (S2 and S3) provided in the circuit. Pressing switch S2 recharges the card with Rs 900 and pressing switch S3 recharges it with Rs 500.
Similarly, interrupt the IR beam at the exit gate. LCD1 should show the number of cars in the parking lot along with ‘Thanks for Visit’ message. No amount should be deducted at the time of exit.
To download the pcb layout, component layout and code for this project click on below button
The system also offers the facility to recharge the amount for each RFID tag. No manual processing is involved. In addition, the system provides security.
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| Block Diagram |
AT89S52 is a low-power, high-performance CMOS 8-bit microcontroller with 8kB Flash memory. It is compatible with the industry-standard 80C51 instruction set and pin-out. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional non-volatile memory programmer. Other features include 256 bytes of RAM, 32 input/output lines, watchdog timer, two data pointers, three 16-bit timers/counters, a six-vector two-level interrupt architecture, a full-duplex serial port, on-chip oscillator and clock circuitry.
CON2 and CON3 are two-pin connectors that connect the 12V DC motors to the circuit for controlling the entry and exit gate boomers. CON4( See component layout for pcb) is a ten-pin dual-in-line female connector that connects the RFID reader module to the circuit.
CON2 and CON3 are two-pin connectors that connect the 12V DC motors to the circuit for controlling the entry and exit gate boomers. CON4( See component layout for pcb) is a ten-pin dual-in-line female connector that connects the RFID reader module to the circuit.
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| Circuit Diagram |
Dual-operational amplifier LM358 (IC4) is used as a voltage comparator to compare the output of the IR sensors with a fixed threshold voltage in order to know whether the IR beam is interrupted or not.
Two IR transmitter-receiver pairs are used. The IR LEDs are connected in forward-biased condition to the +5V power supply through 220-ohm resistors. These emit IR light, which is interrupted when an object comes into its way to the IR receiver. The IR receiving photodiodes are connected in reverse-biased condition to +5V power supply through 1-mega-ohm resistors. When the IR light falls on the photodiodes, their resistance changes and so does their output. This output is compared with a fixed voltage to give a digital output to the microcontroller in order to judge the entry and exit of the vehicles.
LCD display. LCD1 is a two-line, 16-character, alpha-numeric liquid crystal display. Data lines D0 through D7 of the LCD are connected to port 2 of AT89S52 (IC3). Reset (pin no. 4 of LCD) and enable (pin no. 6 of LCD) control lines are connected to port pins pin no. 16 and pin no. 17 of microcontroller, respectively. Control lines control data flow from the microcontroller to LCD.
When power is switched on, LED1 glows to indicate the presence of power in the circuit and LED2 glows to indicate the presence of RFID reader. Simultaneously, the ‘Automatic RFID Car Parking’ message is displayed on LCD1 along with a short beep from piezobuzzer PZ1. Transistor BC547 drives the buzzer.
When a car crosses the IR LED1- IR D1 pair installed at the entry gate, the gate boomer does not open until an RFID tag is placed near the RFID reader. After the tag is placed near the reader, the gate boomer opens for three seconds and closes automatically. If the initial recharge amount was Rs 900, the LCD display shows ‘Vehicle1 Amount’ in the first line and ‘Deducted 100’ in the second line, followed by ‘Balance Amount’ in the first line and ‘800’ in the second line. It is then followed by display of ‘Number of Cars’ in the first line and ‘001’ in the second line. If the parking lot is full, the message “Parking is Full, Sorry for Inconvenience” is displayed on LCD.
When a car leaves the parking area and crosses the IR beam between IR LED2 and IR D2 at the exit gate, the vehicle count decreases by one. The LCD shows the number of cars in the parking lot along with “Thanks for Visiting” message.
Construction and testing
Burn the hex code into the AT89S52 microcontroller using a suitable programmer and then mount the microcontroller on the PCB. Install IR LED1-IR D1 pair at the entry gate such that these face each other. Similarly, install IR LED2-IR D2 pair at the exit gate.
For testing, switch on the circuit, interrupt the infrared beam between IR LED1 and IR D1 with your hand or some other opaque object and then remove it, and place the tag near the reader. The LCD should show the message as described earlier in ‘How this vehicle parking system works’ section. An amount of Rs 100 should be deducted for every interruption of the IR beam. The card can be recharged by pressing the pushbutton switches (S2 and S3) provided in the circuit. Pressing switch S2 recharges the card with Rs 900 and pressing switch S3 recharges it with Rs 500.
Similarly, interrupt the IR beam at the exit gate. LCD1 should show the number of cars in the parking lot along with ‘Thanks for Visit’ message. No amount should be deducted at the time of exit.
To download the pcb layout, component layout and code for this project click on below button