The Linear Quaternary LED Desk Clock You’ve Been Clamoring For

You almost certainly think in a decimal (base 10) numeral system, because that’s what the entire world uses in most situations. But that was a largely arbitrary decision on the part of humanity and the prevailing theory is that we chose it because we have 10 fingers. Sometimes other systems make sense, like binary and hexadecimal in computing. However, you’ve probably never seen a quaternary (base 4) numeral system in use, which is part of what makes Andrei Erdei’s linear LED clock so interesting.

Aesthetically, this clock is all about triangles and so you might assume that it uses a ternary (base 3) numeral system. But each triangle represents a single unit and they’re grouped in threes. If all three are off, that is 0. Then each lit triangle adds one to the count, for a total of four (0-3) when all are lit.

But this isn’t a true quaternary clock because each quaternary count only represents a single decimal digit of the time, rather than the actual total value. Though to be clear, Erdei never claimed that this was a quaternary clock.

If this were really quaternary, the time “12:42” would be displayed as three groups of fully lit triangles in one color, followed by 10 groups of fully lit triangles and another group with one lit triangle in another color.

That would be really hard for our decimal brains to decipher, so Erdei chose a system where each set of triangle groups (distinguished by color) only represents one digit of the decimal time. So “12:42” would be one yellow triangle, two red triangles, four green triangles, and two blue triangles. This is easier and faster for most people to figure out without a piece of paper and a pencil.

The hardware necessary for this to work is much simpler than the concept. A Wemos D1 Mini ESP8266 development board controls the process, connecting to a local WiFi network to pull the time via NTP (Network Time Protocol). It then illuminates the proper positions with the correct colors on a strip of WS2812B individually addressable RGB LEDs. There are a total of 35 LEDs, but some will never come on when displaying the time and are only there to simplify construction and coding. They’re also part of the animation that occurs at startup.

Those components fit into a 3D-printable frame that looks a bit like a backgammon board. Erdei sized it to fit nicely on a desk. That’s the perfect place for it as your coworkers attempt to unravel its mysteries.