Binary Clock · Reading and design
How to read
This face encodes each decimal digit separately, rather than converting the entire hour or minute into one binary number. Read two hour columns followed by two minute columns; enabling seconds adds two more columns on the right.
Within each column, the weights are 8, 4, 2 and 1 from top to bottom. Add the lit values: the bottom dot alone is 1, 4 plus 2 is 6, and 8 plus 1 is 9. An entirely dark column means zero.
A worked example
For 08:25, the four columns are dark, 8, 2, and 4 + 1. Decode them as 0, 8, 2, 5 before grouping hours and minutes. Cover the digits below to practice, then check your answer. Changing between 12-hour and 24-hour time changes the encoded digits too.