There are 10 types of people in this world…those who understand binary and those who don’t.
People have different ideas of what a binary clock should look like. Some binary clocks are easier to read while others take better math skills to figure out in your head. Each clock type has varying degrees of geekyness to it and typically the harder it is to read the more geeky it is.
The BCD Clock
The BCD (Binary Coded Decimal) clock is one of the easier binary clocks to read. It consists of six columns of LEDs, one column for each decimal place. The first column represents the tens decimal place for hours. The second is the ones decimal place for hours. The same is true for minutes and seconds with two columns each; the tens and the ones column.
Each row on the BCD clock represents a different power of two; the top row is 23 (or 8), the 2nd row is 22 (or 4), the third row is 21 (or 2) and the bottom row represents 20 (or 1).
The LEDs represents either a binary 1 when the LED is on or a binary 0 when the LED is off.
To read the BCD clock you basically add up the columns. You add up the row values on the rows that the LEDs are turned on. For example if in the seconds ones column, LED 20 & 22 are turned on, you take the values 20 = 1 & 22 = 4 and add them together to get 1 + 4 = 5. So 5 would be the value of the seconds ones column. You repeat this for each column and then you have the military time in decimal format. Easy as 1-10-11.
| H | H | M | M | S | S | |
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| 22 (4) | |
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| 21 (2) | |
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| 20 (1) | |
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| Time: | 0 | 9 | 3 | 2 | 2 | 0 |
You can purchase BCD clocks for your desk to impress your friends.
The BCD Clock is good for wannabe geeks…but the real geeks need something more…
Horizontal Binary Clock
The BCD Clock is very easy to read. Something a bit more geeky is the horizontal binary clock. Instead of separating each decimal digit the horizontal binary clock separates the hours, minutes & seconds into individual bytes; the first byte being hours, the second minutes and the third seconds. Once you understand binary this clock becomes easy to read also.
| Hours (0 to 23) | Minutes (0 to 59) | Seconds (0 to 59) | |||||||||||||||||||||||
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| 09 | 32 | 20 | |||||||||||||||||||||||
True Binary Clock
The problem with the BCD Clock and the Horizontal Clock is that they both represent time in the traditional 12:60:60 format. The format is not dirived from binary therefore they are not true binary clocks. They are just traditional-binary hybrid clocks. To get a true binary clock you must design a clock that is based off of the number 2.
The True Binary Clock is 2-based. We start off by dividing the 24 hour day into two 12 hour parts. The most significant bit on the left represents 12 hours. When this LED is off that means the time is before 12 (noon) and when it is on the time is after noon. We then divide 12 into two 6 hour parts. The second LED represents 6 hours. So in the morning if the 2nd LED is on the time is after 6am. In the afternoon if it is on it is after 6pm (18:00 24hr clock). The third LED represents 3, the forth is 1.5 or 90 minutes, the fifth is 45 minutes and so on.
At midnight the clock is reset so all LEDs are off. It then starts counting up and at about 11:59pm all the LEDs will be turned on just before it rolls over to the next day where the clock is then reset again.
| Byte 2 | Byte 1 | Byte 0 | |||||||||||||||||||||||
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| 0 | 1 | 1 | 0 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | ||
True Binary Calendar
Taking the True Binary Clock one step further we now have the True Binary Calendar. This binary calendar represents the entire year. At midnight on New Years day the calendar is set so all LEDs are turned off. It then counts up throughout the year until New Years Eve when all the LEDs will be turned on. You can test this by setting your computer clock to December 31 @ 11:59pm.
The most significant LED on the left represents approximately six months and the least significant LED on the right represents about 1.8797 seconds. An interesting fact is during leap year the clock will run slightly slower since there is an extra day that year.
| Byte 2 | Byte 1 | Byte 0 | |||||||||||||||||||||||
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| 0 | 1 | 1 | 0 | 0 | 1 | 0 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | ||