// comms
RC522 RFID
13.56 MHz RFID reader/writer
€2.00
avg eur
no image
I2C
SPI
UART
Pins
7
Specs
4
Libraries
1
Protocols
3
// wiring → esp32 devkit v1
3.3V
3V3
EN
GPIO36
VP
GPIO39
VN
GPIO34
GPIO35
GPIO32
GPIO33
GPIO25
GPIO26
GPIO27
GPIO14
GPIO12
GND
GND
GPIO13
ESP32
WROOM-32
devkit v1
USB
VIN
5V
GND
GPIO23
MOSI
GPIO22
SCL
RST
GPIO1
TX0
GPIO3
RX0
GPIO21
SDA
GPIO19
MISO
MISO
GPIO18
SCK
SCK
GPIO5
SS
SDA / SS
GPIO17
TX2
GPIO16
RX2
GPIO4
GPIO2
GPIO15
sensor pin (left)
sensor pin (right)
unused
// pinout → esp32
| Sensor Pin | ESP32 Connection |
|---|---|
| 3.3V | 3.3V |
| GND | GND |
| SCK | GPIO 18 |
| MOSI | GPIO 23 |
| MISO | GPIO 19 |
| SDA / SS | GPIO 5 |
| RST | GPIO 22 |
// technical specs
Frequency
13.56 MHz (MIFARE)
Range
~3 cm
Voltage
3.3V (NOT 5V tolerant)
Cards
MIFARE Classic 1K/4K, Ultralight
// github libraries
// notes & warnings
3.3V only — feeding 5V kills it. MIFARE Classic crypto is broken (Crapto1) — fine for hobby, never for security.