EM-18 RFID READER MODULE 

The EM-18 RFID Reader Module is a compact and easy-to-use contactless RFID reader designed to read 125 kHz low-frequency (LF) RFID cards and tags. It is widely used in access control systems, attendance machines, door authentication systems, security solutions, and embedded electronics projects.

The module works by generating a 125 kHz electromagnetic field through its internal antenna. When a compatible RFID card or tag enters this field, it is powered inductively and transmits its unique identification number back to the reader. The EM-18 decodes this data and outputs it via a UART (TTL serial) interface or Wiegand format (depending on the model), allowing seamless integration with microcontrollers such as Arduino, ESP32, ESP8266 (with level shifting), and PLC systems.

Operating at 5 V DC, the EM-18 can read cards at distances up to 8–10 cm, depending on the tag type. The module outputs data in ASCII format, making it easy for microcontrollers to process and use for authentication or tracking purposes. Its internal antenna design simplifies wiring and reduces external component requirements, enabling plug-and-play deployment.

Applications include RFID-based access control and security systems, employee attendance tracking, door lock and authentication systems, smart identification solutions, IoT and embedded projects, and educational electronics experiments. Its reliable performance, simple interface, and compact form factor make the EM-18 a popular choice for both professional and DIY RFID applications.