Kristjan Salev

# HOW TO DECODE A BINARY CLOCK

Updated: Jul 19, 2022

A binary clock is a clock that displays time in a binary format. It is also known as the powers of 2 clock, and was first introduced by electrical engineer Lyle Morris. This clock uses six columns of LEDs which represent zeros and ones. Reading this clock needs a little practice, but in reality, it is not difficult at all. But first, let’s examine what is binary number system and how to convert binary numbers to decimal equivalent. The number system is just a way to represent numbers. The decimal number system consists of 10 symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. A binary number system consists of only two symbols: 0 and 1. Decimal and binary number systems are positional number systems, which means every symbol in the number represents a different value depending on where that symbol is located in the number. The value of the position increases as we move from right to left in the number. If we have a decimal number system (we use 10 symbols to represent numbers), that value increases by 10 as we move from right to left. For example, numbers 1, 23, and 2345 can be interpreted as follows:

However, if we have a binary number (using only 2 symbols to represent numbers) and want to convert it to a more familiar decimal number, we use powers of 2 instead of powers of 10. For example, we can find decimal equivalents for the binary numbers 1, 101, and 11101 as follows:

Lets now look at the binary clock and see, how we can read it. The first two columns show the hours, the middle columns show the minutes and the right-hand columns show the seconds. 4 rows represent powers of 2.

Each illuminated LED represents powers of 2. To read each digit in the time, we only have to add the values that each illuminated LED represents. In our example clock reads 20 hours, 5 minutes, and 29 seconds.

Let's take another example:

In these two examples, we read the clock in binary coded decimal mode (BCD mode). It is also possible to read the clock in direct binary mode. In this mode, binary numbers are coded in rows. 6 columns represent powers of 2.

Now we again have to add the values that each illuminated LED represents. In doing so, we find that the clock shows: 16+4+2=22 hours, 32+4+2+1=39 minutes, and 16+8=24 seconds.

Can You tell now, what time the binary clock in the picture below shows in BCD mode?