ESP8266WiFi // Wemos D1 Mini // RFID reader


Have any of you done this project?

I’m having some issues compiling this sketch for the Wemos D1 Mini.
Not even the example card is working:

“Error compiling for board NodeMCU 1.0 (ESP-12E Module).”
“Error compiling for board LOLIN(WEMOS) D1 R2 & mini.”

Seems to compile just fine for me:

(however, I’m using PlatformIO and not the Arduino IDE)

What are the specific errors that you’re getting?

Arduino: 1.8.9 (Windows 7), Board: “LOLIN(WEMOS) D1 R2 & mini, 80 MHz, Flash, Disabled, All SSL ciphers (most compatible), 4M (no SPIFFS), v2 Lower Memory, Disabled, None, Only Sketch, 921600”

Build options changed, rebuilding all
In file included from C:\Users\ajn\Documents\Arduino\libraries\ESP8266WiFi\src/WiFiClientSecureBearSSL.h:29:0,

             from C:\Users\ajn\Documents\Arduino\libraries\ESP8266WiFi\src/WiFiClientSecure.h:41,

             from C:\Users\ajn\Documents\Arduino\libraries\ESP8266WiFi\src/WiFiServerSecure.h:20,

             from C:\Users\ajn\Documents\Arduino\libraries\ESP8266WiFi\src/ESP8266WiFi.h:41,

             from C:\Users\ajn\Documents\Arduino\Homey_RFID\Homey_RFID.ino:1:

C:\Users\ajn\Documents\Arduino\libraries\ESP8266WiFi\src/BearSSLHelpers.h:148:34: error: ‘virtual const unsigned char* BearSSL::HashSHA256::oid()’ marked override, but does not override

 virtual const unsigned char *oid() override;


Multiple libraries were found for “ESP8266WiFi.h”
Used: C:\Users\ajn\Documents\Arduino\libraries\ESP8266WiFi
Not used: C:\Users\ajn\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.5.2\libraries\ESP8266WiFi
exit status 1
Error compiling for board LOLIN(WEMOS) D1 R2 & mini.

This report would have more information with
“Show verbose output during compilation”
option enabled in File -> Preferences.

I think this is the problem: you have two versions of ESP8266WiFi installed, and they might be conflicting. Remove the first one (in C:\Users\ajn\Documents\Arduino\libraries\) and try again.