Binary clock

A binary clock is usually a clock which displays traditional sexagesimal time in a binary format. Originally, it showed each decimal digit of sexagesimal time as a binary value, but presently binary clocks also exist which display hours, minutes, and seconds as binary numbers. Most binary clocks are digital, although analog varieties exist. True binary clocks also exist, which indicate the time by successively halving the day. Thus these clocks do not use hours, minutes, or seconds. Similar clocks, based on Gray coded binary, also exist.

Binary-coded decimal clocks

Reading a BCD clock: Add the values of each column of LEDs to get six decimal digits. There are two columns each for hours, minutes and seconds.

As of 2008, the most common binary clocks sold are designed by Anelace Inc., and use six columns of LEDs to represent zeros and ones. Each column represents a single decimal digit, a format known as binary-coded decimal (BCD). The bottom row in each column represents 1 (or 2⁰), with each row above representing higher powers of two, up to 2³ (or 8).

To read each individual digit in the time, the user adds the values that each illuminated LED represents, then reads these from left to right. The first two columns represent the hour, the next two represent the minute and the last two represent the second. Since zero digits are not illuminated, the positions of each digit must be memorized if the clock is to be usable in the dark.

How to read binary

In binary:
0 -> 0
1 -> 1
2 -> 10
3 -> 11
4 -> 100
5 -> 101
6 -> 110
7 -> 111
8 -> 1000
9 -> 1001
10-> 1010
11-> 1011
12-> 1100
If numbers were displayed this way you could not tell the difference between 1, 2, 4, and 8, therefore all numbers are padded with leading zeros, so as to be four digits.
Thus:
0 -> 0000
1 -> 0001
2 -> 0010
3 -> 0011
4 -> 0100
5 -> 0101
6 -> 0110
7 -> 0111
8 -> 1000
9 -> 1001
(light = 1, dark = 0)

Binary Coded Sexagesimal

The latest version of the binary clock can also use binary coded sexagesimal (base 60) to give the time (one number each for hours, minutes, and seconds) rather than six numbers for the decimal digits of the time units. Numbers are then displayed horizontally:

Time Technology's Samui Moon binary coded sexagesimal wristwatch. 3:25 on this clock

	Hours	Minutes	Seconds
32		1	1
16		0	1
8	1	0	0
4	0	1	0
2	1	0	0
1	0	1	1
	10	37	49

A binary clock circuit displaying 13:49:37

The above display uses three binary number columns, one for each of the units (hours, minutes and seconds) of the conventional time system.

See also

• Hexadecimal time

External links

• Binary clock made in Flash
• Binary clocks as applications (for Windows)