Callisto Digital VFD Tube Clock Uses an ESP32 to Automatically Sync Time

Hirito Kaku’s clock automatically adjusts to daylight savings time, dims itself based on lighting, and turns off at night.

Cabe Atwell
3 years agoClocks / Sensors / Internet of Things

There have been a number of interesting clock projects that made use of Nixie tubes, with their distinct orange or blue glow, but few have as many features as Hirito Kaku’s Callisto digital clock.

Kaku designed his clock with inspiration from Lady Ada’s Ice Tube and mcer12’s Flora-ESP826 timepieces, both of which pack vacuum fluorescent displays (VFDs) and modern cases. That said, Callisto was brought to life using a series of Russian IV-18 VFDs driven by an ESP32 microcontroller and housed inside a 3D-printed angled enclosure.

The clock can be configured via a web browser and automatically syncs time over a Wi-Fi connection. It also automatically switches to daylight savings time, auto-dims based on light conditions and powers down during the night to save power and extend tube life. A handy touchpad on the side of the case allows users to briefly see the time during evening hours and enter the configuration mode.

Kaku has uploaded all the necessary files on his GitHub page for those who would like to recreate Callisto and even included an extensive manual with operating instructions and troubleshooting features.

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