How to Use EM-18 RFID READER MODULE: Examples, Pinouts, and Specs

The EM-18 RFID Reader Module is a compact and efficient device designed for reading RFID tags. Operating at a frequency of 125 kHz, it can detect and read RFID tags from a distance of up to 10 cm. The module outputs the tag data in a serial format, making it highly compatible with microcontrollers, such as Arduino, and other digital systems.

• Access control systems (e.g., door locks, attendance systems)
• Inventory management and tracking
• Payment systems
• Security and authentication systems
• Embedded systems requiring RFID functionality

Below are the key technical details and pin configuration for the EM-18 RFID Reader Module:

The EM-18 module has a total of 7 pins. The table below describes each pin:

1. Power the Module: Connect the VCC pin to a 5V DC power source and the GND pin to ground.
2. Connect to a Microcontroller:
   • Connect the TX pin of the EM-18 to the RX pin of the microcontroller (e.g., Arduino UNO).
   • Ensure the microcontroller's UART baud rate is set to 9600 bps to match the module's output.
3. Read RFID Tags:
   • When an RFID tag is brought within the module's range (up to 10 cm), the module reads the tag's unique ID.
   • The ID is transmitted via the TX pin in a serial format.
4. Optional Connections:
   • Use the BEEP pin to control an external buzzer for audible feedback.
   • Use the LED pin to control an external LED for visual feedback.

• Power Supply: Ensure a stable 5V DC power supply to avoid erratic behavior.
• Tag Compatibility: Use only 125 kHz passive RFID tags for proper operation.
• Interference: Avoid placing the module near metal objects or other electronic devices that may cause interference.
• Antenna Range: Ensure the RFID tag is within the specified range (up to 10 cm) for reliable reading.

Below is an example of how to connect and use the EM-18 RFID Reader Module with an Arduino UNO:

// EM-18 RFID Reader Module Example with Arduino UNO
// Connect EM-18 TX pin to Arduino D2 (SoftwareSerial RX)

#include <SoftwareSerial.h>

// Define SoftwareSerial pins for EM-18
SoftwareSerial RFID(2, 3); // RX = Pin 2, TX = Pin 3 (TX not used here)

void setup() {
  Serial.begin(9600);       // Initialize Serial Monitor at 9600 bps
  RFID.begin(9600);         // Initialize SoftwareSerial for EM-18 at 9600 bps
  Serial.println("EM-18 RFID Reader Ready");
}

void loop() {
  if (RFID.available()) {   // Check if data is available from EM-18
    String tagData = "";    // Variable to store RFID tag data
    while (RFID.available()) {
      char c = RFID.read(); // Read each character from EM-18
      tagData += c;         // Append character to tagData
    }
    Serial.print("RFID Tag ID: ");
    Serial.println(tagData); // Print the tag ID to Serial Monitor
  }
}

• Ensure the RFID tag is within range when testing.
• Use the Serial Monitor (set to 9600 baud) to view the tag ID.

1. Can the EM-18 read multiple tags simultaneously?

   • No, the EM-18 can only read one tag at a time.

2. What is the maximum range of the EM-18?

   • The maximum range is approximately 10 cm, depending on the tag and environmental conditions.

3. Can I use the EM-18 with a 3.3V microcontroller?

   • Yes, but you will need a level shifter to safely interface the 5V TX output with the 3.3V RX input of the microcontroller.

4. Does the module support 13.56 MHz RFID tags?

   • No, the EM-18 only supports 125 kHz passive RFID tags.

By following this documentation, you can effectively integrate the EM-18 RFID Reader Module into your projects for reliable RFID tag reading.