Gwiot 7941E+ V1.1 125kHz RFID Reader Module with UART TTL Output

The 7941E+ V1.1 is a low-frequency RFID reader module manufactured by Gwiot, designed to read 125kHz EM4100-compatible cards and output the card identifier over a serial UART interface. It is a compact, read-only module that integrates the RFID radio circuit and antenna on a single board, making it a practical choice for access control, time and attendance systems, parking management, and Arduino-based RFID projects.

The module operates on a 5V DC supply and draws approximately 40mA, keeping power requirements modest for embedded installations. Card reading is performed at 125kHz, the standard low-frequency band used by EM4100 cards, and the detected card number is transmitted over a one-way UART TTL line at 9600bps. The board exposes VCC, GND, and a TX/D0 data pin, allowing direct connection to the hardware serial port of an Arduino, ESP32, STM32, or any microcontroller with a UART receiver. Detection range is specified at 3 to 5 centimeters on the product listing, and the module measures 47mm × 26mm × 5mm.

Because the 7941E+ V1.1 is a reader-only device, it cannot write data to cards or modify stored card information, which makes it suitable for security-focused applications where card data should remain immutable. The module is compatible with the Gwiot 7941E library ecosystem, and its UART data frame follows the standard Gwiot format: a start byte (0x02), length byte, card type byte, four card-number bytes, a BCC check byte, and an end byte (0x03). This predictable frame structure simplifies parsing on the host microcontroller. The module is commonly used in door access control, attendance terminals, parking gates, simple security systems, and educational electronics projects.