Binary Clock
Sooner or later I had to make one of these. A binary clock.
It can obtain its power from a USB port for convenience. Mobile phone AC adaptors are also suitable.
The slight "ghost glow" of the dark LEDs also enables the observer to identify the time in total darkness. If, for example, only one LED is on then it would not be possible to know which one it is if the other LEDs were not visible.
