Although [Serokoy] is not thrilled with the outcome of his
Nipkow disk clock (translated), but we really enjoy it. It uses
the Persistence of Vision concept to create a light display from
a rotating disk. We’ve come across a lot of rotating disk
clocks. Several were based off of the platters of a hard drive,
using a slit, or series of slits to make up the display. This
Nipkow disk uses a similar technique but in a more general way.
The series of holes arranged in a spiral pattern allows a grid
of concentric rings to be used as pixels when the disk is
spinning. The bottom portion of the disk is used as the display
area. Each pixel is illuminated at just the right time by LEDs
below in order to freeze that pixel in the viewer’s eye. The
demo is a bit rough, and [Serokoy] mentions that the precision
of the hole layout makes all the difference. He drilled these by
hand in a CD which was spray painted matte black. Even though he
used a computer to lay out and print a template, it took four
tries to get a suitable