There’s no doubt that the 7-segment display is a gold standard for displaying lighted digits. But what about a throwback to an older system of displaying numbers — Cistercian? With thirty-one 0805 LEDs, [Josue Alejandro] made a simple module displaying a single Cistercian digit (any from 0-9999).
The first iteration used castellated edges and required a significant number of GPIO, so on the next rev, he switched to a serial-to-parallel converted from Lumissil (IS31FL3726A). A diffuser and spacer were printed from PLA and made for an incredibly snazzy-looking package.
Of course, it couldn’t stop there, and a third revision was made that uses SK6812 Neopixels, allowing full RGB capability. All the design documents, layout files, and incredibly detailed drawings are available on GitHub. What makes this incredibly handy is having a module you can easily add to a project. Perhaps even as a component in an escape room in a box that would allow you to flash multiple numbers. Or perhaps as a stylish clock. We’d even go so far as to challenge someone to create a calculator by combining several of these modules with this keypad.
Don’t feel bad if you don’t know what Cistercian numbers are. Unless you’re a monk of the Order of Cistercia, there’s really no reason for you to learn the cipher that stretches back to the 13th-century. But then again, there’s no reason not to use the number system to make this medieval-cool computer number pad.
If you haven’t been introduced to the Cistercian number system, it’s actually pretty clever. There are several forms of it, but the vertical form used here by [Tauno Erik] is based on a vertical stave with nine glyphs that can be attached to or adjacent to it. Each glyph stands for one of the nine numerals — one through nine only; there’s no need for a zero glyph. There are four quadrants around the stave — upper right, upper left, lower right, and lower left — and where the glyph lies determines the multiplier for the glyph. So, if you wanted to write the number “1234”, you’d overlay the following glyphs into a single symbol as shown.
[Tauno]’s Cistercian keypad, admittedly more of an art and history piece than a useful peripheral, somehow manages to look like it might have been on the desk of [Theodoric of York, Medieval Accountant]. Its case is laser-cut birch plywood, containing a custom PCB for the 20 keyboard switches and the Xiao RP2040 MCU that runs the show. Keycaps are custom made from what looks like oak combined with a 3D-printed part, similar to his previous wooden keycap macro pad. Each of the nine Cistercian glyphs is hand-carved into the keycaps, plus an imaginary glyph for zero, which wasn’t part of the system, as well as operators and symbols that might have baffled the medieval monks.
The native Cistercian system is limited to numbers between 1 and 9,999, so we’ll guess that the keypad just outputs the Arabic numeral corresponding to the Cistercian key pressed and doesn’t actually compose full Cistercian numbers. But the code to do that would be pretty easy, and the results pretty cool, if a bit confusing for users. Even if it’s just for looks, it’s still a cool project, and we doff the hood of our monkish robe to [Tauno] for this one.
It’s rare for the fields of the engineer and the mediaevalist to coincide, but there’s a clock project bringing the two fields together. The Cistercian monastic order used an intriguing number system from the 13th century onwards that could represent any four-digit number as a series of radicals expressed in the four corners of a single composite symbol, and it’s this number system that’s used by the clock to render the full range of 24 hour time on a large 5×7 LED matrix mounted on a wooden base.
Every numeral has a line down the middle, and the system uses the four quadrants of space around it to display the ones, tens, hundreds, and thousands positions starting in the upper right corner.
[andrei] adapted the system to show time by assigning tens of hours to the thousands quadrant in the bottom left, hours to the hundreds quadrant in the bottom right, tens of minutes in the upper left, and minutes in the top right. The tricky part is that the system has no zero, but [andrei] just darkens the appropriate quadrant to represent zero.
The timekeeping is done with an ESP-01, and there are a total of 31 RGB LEDs including the middle bit, which blinks like a proper digital clock and doubles as a second hand. As usual, [andrei] has provided everything you’d need to build one of these for yourself. We admit that the system would take a little time to learn, but even if you never bothered to learn, this would make a nice conversation piece or focal point for sitting and staring. Take a minute to check it out in action after the break.