Binary Clock is clock for geeks. It displays the current time (hours, minutes. And seconds) in binary.

Impress all your friends, by buying a binary clock and standing it on the corner of your desk. It is impressive, and reads in two different modes commonly used to display time in binary. No matter which mode you might be faced with, you can now tell time following these simple steps. You also might want to buy a wrist watch, in binary mode and be one step ahead of most of your friends.

The idea of the binary clock is relatively simple. Instead of displaying numbers in base 10 (which most people are used to), it uses binary (base 2) which only uses 1s and 0s. Because there are only two digits, lights can be used in place of the digits. "On" signifies a 1 and "Off" means 0. Reading the clock is only a matter of converting the binary value to decimal.

• Decode each binary digit. The clock is divided into three sections, each containing two columns of lights. The first section displays hours, the second minutes, and the final section tells the seconds. The first column in each section represents the first digit (10's place) and the second column displays the second digit (or 1's place). Each column is composed of 2-4 lights, each representing a power of two. Starting at the bottom, the first light represents 2⁰(1), the second represents 2¹(2), the third is 2²(4), and the top light represents 2³(8). In the picture, you can easily see this by the numbers to the left of each row.
  Add the corresponding values of every light in the column that is lit to find the appropriate number. For example, if the bottom three lights are lit, the number is 4 (third row) + 2 (second row) + 1 (bottom row) = 7. (See the second digit of the minutes in the picture.)
• Read the hour by decoding the first section. In the picture, the bottom light (first row represents 1) in the first column is lit and the second column is blank (0). Combining the digits, you get 10 o'clock.
• Find the minutes using the same process as before. Again looking at the picture; in the middle section, the first two (bottom) lights in the first column are lit (second row represents 2 and the first row is 1; 2 + 1 = 3) and the first three in the second column are lit (third row represents 4, second 2, and first 1; 4 + 2 + 1 = 7), combining the two digits, we find it is 37 minutes past the hour.
• Decode the seconds. This can sometimes be tricky on an active clock because the seconds are ever changing. In the picture, the third light in the first column (third row represents 4) and the fourth and first light in the second column (fourth row is 8 and first is 1; 8 + 1 = 9) are lit, displaying 49 seconds. If you forget what number a light stands for, look at the number directly to the left of the row.
• Combine the numbers to read the time. (more)

• What is the Binary Clock?
• How to read a Binary Clock?