In this project an ESP8266 is used to emulate a DCF77 which might not work properly due to interferences or bad connection. The main project idea is from Elektor Magazine (DCF77 emulator with ESP8266) (original PDF article). The NTP client implementation was not working properly so I replaced it with a NTP client solution provided by ESP8266/ESP32 (Getting Current Date and Time with ESP8266 [...]) which is working more reliable and the code is slimmer.