New 303WIFILC01 firmware

This is repository is my development of new firmware for a 7-segment clock I bought on AliExpress. The default firmware uses NTP, which i found pretty neat, but it seems to be hardcoded to CST (China Standard Time), which is not neat at all.

Acknowledgement

This project would never have begun without finding the work by Maartin Pennings, who have a repository at: https://github.com/maarten-pennings/303WIFILC01. Some good documentation on the NTP services in the ESP8266 can be found at: https://werner.rothschopf.net/202011_arduino_esp8266_ntp_en.htm and https://werner.rothschopf.net/microcontroller/202112_arduino_esp_ntp_rtc_en.htm and a really helpful thread at: https://forum.arduino.cc/t/getting-time-from-ntp-service-using-nodemcu-1-0-esp-12e/702333.

Time sources

The clock is using the RTC and the NTP to keep the clock current.

• When the clock initialises it starts running from the RTC
• If a connection to the internet is established it updates the RTC from NTP
• The RTC will continue to update from NTP every 12 hours
• RTC runs on UTC

Configuration

The clock has a built-in web server to configure:

• WiFi access configuration (SSID & PSK)
• The NTP server to use
• The time zone

Y2K38

At the time this code was written, the ESP8266 time_t value uses signed 32 bit. That means that the esp8266 time functions will suffer from the the Y2K38 problem: https://en.wikipedia.org/wiki/Year_2038_problem. This means that the esp8266 time library code will malfunction starting 03:14:07 on Tuesday, 19 January 2038 GMT.

To do

As always write more documentation.

• Initial things to study
  • Write or find some example code for the RTC (DS1302).
  • Write or find some example code for the display chip (TM1650).
  • Write or find some example code for using NTP.
• Code design
  • Decide how to tie the RTC in with NTP.
  • Decide how much should be configurable via HTTP
  • Decide how to use the flash memory.
• Write code
  • Time display
  • RTC code
  • NTP code
  • Make use of the LED on the back og the board.
  • Put WiFi to sleep when unused
  • Update the display via timer interrupt
  • Web server code
  • Websocket server code
  • Remember 12 hour mode
  • Rechargeable battery support for the RTC
  • Save config as JSON file in the FS
  • mDNS
  • Web page for configuration
    • Configuration from web page to and from clock
    • Set AP mode when no WiFi connection could be established
    • Get time-zone from browser