NTP clock on 4 OLED displays

    I wanted to created a special clock as a vintage clock with VFD display, so I realised ca easiest way is to use an i2c expander as TCA9584A chip/module.

   I used info from article Guide for TCA9548A I2C Multiplexer: ESP32, ESP8266, Arduino

   I used this schematic:

and I tested Santos's sketch:

   For a real NTP clock with DST selector (winter/summer time) I used this schematic and NTP_clock_TCA9548A_4OLEDs_1.ino sketch:

so combined schematic

   For DST=1 (summer time):

and for DST=0 (winter time)

  I uploaded 2 movies:

- NTP clock on 4 OLED displays

- NTP clock on 4 OLED displays (2)

After than I added the feature to see clock as VFD display, as in article 

Ceas NTP cu cifre din 7-segmente pe 4 afisaje OLED using my original sketch NTP_clock_TCA9584A_4OLEDs_3.ino

so you find how clock is in this video:

- NTP clock with 7-segment numbers on 4 OLED displays

- NTP clock with 7-segment numbers on 4 OLED displays (2)

   I moved the project from breafboard to a classical PCB (sandwich) with 2 PCBs):

so you can see the 2 other videos:

- NTP clock with 7-segment numbers on 4 OLED displays (3)

- NTP clock with 7-segment numbers on 4 OLED displays (4)

Bibliography:

- Ceas NTP pe 4 afisaje OLED

- Reproducere numere si caractere din 7 segmente pe afisaj OLED

- Ceas NTP cu cifre din 7-segmente pe 4 afisaje OLED