[Barzok] has a very minimal clock build. It takes a handful of LED arrays with an integrated driver, an Arduino Nano, a real-time clock module, and a voltage regulator.

If you have ever wanted to build your very own binary Nixie Clock you may be interested to know that a kit is available with optional housing and Arduino board priced from $69. “All SMD ...

Check out this smart shelving system driven by an Arduino and using LEDs, which serves as a clock.

The clock part works as you probably expect — an Elegoo Nano fetches the time from a real-time clock module and displays it on the WS2812B LED strips arranged in 7-segment formations.