Full customization for time zones: You can change the offset for Daylight savings or Std (or none at all) and when it starts and stops.
Displays Hours, Minutes, Seconds, Tenths, Hundredths of seconds
Easy setup up: Press the setup button within 5 seconds of power-on to force into AP mode. Connect to ESP-CLOCK-XXXXX and go to http://192.168.4.1 to configure Wifi settings
Password protected: Unique to each ESP card, displayed on power on
Firmware updates: Can be updated by user remotely
Fine adjust: Can tune clock by seconds
Customization for NTP Server and sync interval (minimum of 60 seconds)
Displays signal strength, last sync, first sync times
Dim the display for night time
Can run off of a standard USB Charger power supply
Can change between 12 and 24 hour mode
Handles leap seconds
This clock uses the GPIO pins on the ESP8266-01 module to connect to 2 Adafruit 7 segment display backpacks. A momentary ON switch is also used to put the clock into program mode. A basic schematic includes a 3.3v regulator, the ESP8266, the two displays and the button. The clock can use a 5v input such as a USB charger.