It works like anything does in metric, with days as the base unit.
It can show decidays, centidays, millidays, and microdays.
For reference, 864 seconds are in a milliday.
Again for reference, six in the morning is 2:5:0:000, noon in 5:0:0:000, and 6 in the evening is 7:5:0:000.
I personally believe that a metric clock would simplify time-keeping, and should be use instead of the current system. A metric clock would make sense, as opposed to what is in place now.
Changes since the first version:
Not in binary
On an LCD
Can show microdays
Can be set without a computer
Step 1: Supplies
1 LCD (must be compatible with Hitachi HD44780 driver)
1 10k potentiometer
2 10k resistors
1 Arduino (or clone)
Lots of wire