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esp8266 (OLED) and RFID-RC522

1 min read
electronics arduino

Board Wiring

Use following wiring if you have ESP8266 with 0.96 OLED screen from IdeaSpark. I got mine for cheap on AliExpress1.

RC522 ESP8266
SCK D5
MISO D6
MOSI D7
SDA D2
RST D1
3V3 3V
GND G

This is the board i got:

2026-02-18_17-09-14_screenshot.png

Code

It's a bit different than wireing standard 8266, because it has OLED screen, which takes pins D5 and D6 for itself, and there's no other alternatives but to reuse them and disable OLED. This scheme and bunch of other useful info could be found at manualplus2. 

#define RST_PIN D1
#define SS_PIN D2

Simple code to test reading

#include <SPI.h>
#include <MFRC522.h>

#define RST_PIN D1
#define SS_PIN D2

MFRC522 mfrc522(SS_PIN, RST_PIN);

void setup() {
  Serial.begin(9600);
  delay(3000);
  SPI.begin();
  mfrc522.PCD_Init();
  Serial.println(mfrc522.PCD_PerformSelfTest() ? "RC522 OK" : "RC522 FAIL");
  Serial.println("Scan a card...");
}

void loop() {
  if (!mfrc522.PICC_IsNewCardPresent()) return;
  if (!mfrc522.PICC_ReadCardSerial()) return;
  Serial.print("UID: ");
  for (byte i = 0; i < mfrc522.uid.size; i++) {
    Serial.print(mfrc522.uid.uidByte[i], HEX);
    Serial.print(" ");
  }
  Serial.println();
}

Footnotes:

1

IdeaSpark esp8266 with 0.96 OLED Screen - https://www.aliexpress.com/item/1005005242283189.html

2

Manual for 8266 - https://manuals.plus/ae/1005005242283189