It is important to note that the SIM800L module requires a stable power supply of at least 2A, it is strongly recommended to use an external power supply to power the SIM800L module. The SIM800L's VCC ...

Arduino-ESP8266-Accurate-NTP-Clock An accurate NTP Clock for Arduino or ESP8266 using a DS3231 or similar RTC module A.N.T. Accurate Ntp Time A Proof Of Concept attempt to get accurate (ish) time from ...