Why I made this

My main reasons for this project were to add a choice of hand movement styles—particularly Swiss railway-style Hold&Start—and automatic daylight-saving changes with selectable time zones.

The Chouchin-CH899 already has capable hardware. I wanted to build on that, making the clock more flexible and easier to configure without replacing the movement.

What the upgrade adds

• Selectable hand movement: Sweep, Burst or railway-style Hold&Start, where the second hand pauses at 12 before starting the next minute.
• Selectable time zones and automatic DST: choose the appropriate time zone and let the clock handle seasonal changes automatically.
• Second-hand battery saving: normal operation, overnight parking or continuous parking while the hour and minute hands keep time.
• Two configurable NTP servers: a fallback server provides another option when the first does not respond.
• Configurable daily synchronisation: choose the clock’s daily Wi-Fi wake time.
• Local web settings: configure the clock from a phone or computer without rebuilding the firmware.

Installing the firmware

Both chips need their respective firmware. The GitHub repository contains prepared downloads, wiring diagrams and separate flashing instructions for the HC32 and Wi-Fi chips.

A guided Windows launcher helps with flashing the TXW813 Wi-Fi chip, including file selection and connection checks.

Check your movement before starting: this project supports the HC32L130/TXW813 revision, not the older MM32/ESP8285 version. Follow the wiring and power instructions carefully.

Get the firmware and installation guides

Testing and feedback

Development and longer-term testing are ongoing. If you experience a bug or unexpected behaviour, please let me know through GitHub Issues.

Include your firmware versions, settings and a description of what happened. If the clock stops, the hand positions and LED behaviour are particularly useful.