We know in offices, shopping malls and in many other places where only the person with authorization card is allowed to enter the room. These systems use RFID communication system. RFID is used in shopping malls to stop theft as the products are tagged with RFID chip and when a person leaves the building with the RFID chip an alarm is raised automatically. The RFID tag is designed as small as part of sand. The RFID authentication systems are easy to design and are cheap in cost. Some schools and colleges nowadays use RFID based attendance systems.
In this project we are going to design a RFID based toll collection system for security purposes. So this system open gates and allow people only with the authorized RFID tags. The authorized tags holder ID’s are programmed in to the ATMEGA Microcontroller and only those holders are allowed to leave or enter the premises.
Hardware: ATmega32 microcontroller, power supply (5v), AVR-ISP Programmer, JHD_162ALCD (16×2 LCD module), 100uF capacitor (connected across power supply), button, 10KΩ resistor, 100nF capacitor, LED (two pieces), EM-18 (RFID reader module), L293D motor driver IC, 5V DC motor.
Software: Atmel studio 6.1, progisp or flash magic.
In the RFID toll collection system circuit shown above, PORTA of ATMEGA32 is connected to data port of LCD. Here we should remember to disable the JTAG communication in PORTC to ATMEGA by changing the fuse bytes, if we wans to use the PORTC as a normal communication port. In 16×2 LCD, there are 16 pins over all if there is a back light, if there is no back light there will be 14 pins. We can power or leave the back light pins. Now in the 14 pins there are 8 data pins (7-14 or D0-D7), 2 power supply pins (1&2 or VSS & VDD or gnd & +5v), 3rd pin for contrast control (VEE-controls how thick the characters should be shown), 3 control pins (RS & RW & E).
In the circuit, you can observe that I have only took two control pins. This gives the flexibility of better understanding. The contrast bit and READ/WRITE are not often used so they can be shorted to ground. This puts LCD in highest contrast and read mode. We just need to control ENABLE and RS pins to send characters and data accordingly.
Read More: RFID Based Toll Collection System