RDM6300 125 kHz RFID reader with ESP32

Supply 5 V Bus GPIO

Pins and ESP32 wiring

Pin	Role	ESP32 pin	Notes
TX	Output (the part drives it)	D25	UART 9600 baud at 5 V level: use a voltage divider to an ESP32 RX pin
RX	Not wired to the ESP32	—	Not used
NC	Not wired to the ESP32	—	Not connected
GND	Ground	GND
5V	Power	VIN	5 V only
ANT1	Not wired to the ESP32	—	Antenna coil
ANT2	Not wired to the ESP32	—	Antenna coil
LED	Not wired to the ESP32	—	Card indicator output, optional
VCC2	Not wired to the ESP32	—	Second 5 V pin (same as 5V)
GND2	Ground	GND

Suggested wiring for the 30-pin ESP32 DevKit, avoiding flash, input-only and strapping pins. BoardPilot checks it for you as you wire.

This module is sold for 5 V. Its outputs may be 5 V: use a level shifter or a voltage divider on ESP32 inputs.

void setup() {
  Serial.begin(115200);
  pinMode(25, INPUT);  // TX
}

void loop() {
  Serial.println(digitalRead(25));
  delay(100);
}

Seeed RDM6300 125 kHz card reader module datasheet, P1: TX, RX, NC, GND, +5V; P2: antenna; P3: LED, +5V, GND; UART 9600 8N1

Part data: CC BY 4.0, free to reuse with credit to BoardPilot.