VFD Tube Clock
This clock is an updated version of an older kit by Cambridgeshire-based Neon Things. The update isn’t to the VFD tubes, which are ancient bits of Soviet display kit now found on internet auction sites. The update is instead to the software that runs the clock. Whereas the previous version of this clock ran on an Arduino, this uses CircuitPython, making it considerably more user-friendly for anyone with Python as a first language.
Even better, thanks to I2C, you can connect this clock to anything you want, turn it into a temperature readout, stock price monitor, or anything else that uses four seven-segment displays.