Those last two digits are the XOR of the tag number. First 10 bits are RFID tag number, which is the unique ID and last two digits are used for error testing. The UART output provides 12-bit ASCII data. In few cases, the UART pin of the 3.3V microcontroller is often 5V tolerant. We could use another microcontroller which uses a lower logic level, but in such cases, the additional logic level converter is required. One thing needs to be kept in mind that the output of EM-18 reader uses 5V logic level. This module also has additional power option. Here is the RFID board module we are using with pin names. We are using a module which is easily available in the market and has complete circuitry with a buzzer, led, and an additional RS232 port. When a Valid frequency tag is brought into the magnetic field of the EM-18 reader, the BC557 transistor gets on and the buzzer will start beeping, it also glows the LED. The module uses UART communication protocol in 9600 Baud rate. If we see the datasheet ( ) of EM-18 Module we could see the backside of the module and the application circuit: Here are the RFID card and tags we are using for this project. We will use 125Khz Passive RFID cards which holds the unique ID data. Few of them use different frequency for communication purpose. Different kind of RFID tags with a different kind of shapes and sizes are available in the market. There are three types of RFID tags available, Passive, Active or Battery-assisted passive. EM-18 module use Oscillator, demodulator and data decoder to read data from a passive card. EM-18 RFID module use 125 KHz RF frequency to read passive 125 KHz RFID tags. In this project, we chose EM-18 RFID module, which is small-sized, low cost, and power efficient module.

We will simply read the unique identification no. Here we are using PIC Microcontroller PIC16F877A for interfacing RFID. If we select a microcontroller without UART, we need to implement software UART.

To read the Passive RFID cards and tag, we need a microcontroller with UART hardware. RFID is very convenient and easy technology. RFID module can read or write small amount of data into a Passive RFID tag, which can be used in identification process in various systems like Attendance system, security system, voting system etc. RFID stands for Radio Frequency Identification.

Em18 rfid reader library for proteus