What Is The Hour? It’s XVII O’ Clock

A glowing pocket watch with Roman numerals.

When live-action role playing, or LARPing, one must keep fully in tune with the intended era. That means no digital watches, and certainly no pulling out your fantastic rectangle from the future to find out if you’re late picking up the kid.

The guts of a pocket watch with glowing Roman numerals.So what do you do when you’re LARPing at 2 PM, but you gotta be back at the soccer practice field by 5 PM? Well, you fashion a period-appropriate timepiece like [mclien]’s 17 o’ Clock. Visually, it’s about as close to a pocket sundial as you can get. It’s deliberately non-connected, and its only function is to tell the time.

But how? If you visually divide the watch across the top and bottom, you get two sets of Roman numerals. The top half handles the hour, and the bottom half the minute. [mclien] started designing this in 2018 and picked it back up in the second half of 2024.

Back to the non-connected part. The only permanently-powered part of the project is a high-precision real-time clock (RTC). The rest uses a power latching circuit, which turns on the Adafruit Trinket M0 to show the time using a NeoPixel ring. Be sure to check out the awesome project logs with fantastic pictures throughout.

Looking for a smarter pocket watch? It’s time you built one yourself. And speaking of pocket sundials…

18 thoughts on “What Is The Hour? It’s XVII O’ Clock

  1. That’s period perfect alright, question is “What period?” It’s still an electronic watch. Why can’t I build a website with a similar display and access that with my phone? Alternatively I could burn a known length of rope and that would tell me when it’s time to leave. You’re already leaving! The LARP Police aren’t going to scoop you up.

    1. If it’s the classical roman period, then it should only have the hours for 1-12 because the night was not counted and zero was not used, and the length of an hour would change according to latitude and the day of the year. Night time was measured using water clocks, so the number of hours per night would change according to the length of the day – or they would adjust the rate of the clock depending on who was using it for what purpose. Either way it was nowhere constant. No minutes either. If it’s a 12 or 24 hour clock with minutes, then it’s already into modern horology and having a dial indicator clock with roman numerals would not be out of place.

    1. One could just get a cheap digital watch and put it in an old (or fabricated) pocket watch case. When it’s closed, it wouldn’t look modern, and it would only be open long enough for a glance.

      1. Yeah that’s what pretty much everybody does. But that is the point: you are still hiding it. This one is meant to be carried openly in a Tolkien like world setup to be a magical device with enhances your feeling for time.

    2. It’s not hard to get a real portable sundial, you want a ring dial. They come in fixed-latitude versions that are small enough to wear as a ring, but the universal and more accurate version is an equinoctal kind like this which has more adjustment. (It’s not my listing, just an example) https://www.ebay.com/itm/176642322009
      There’s better information available about a more expensive modern clone which might be a little smaller but is basically the same. https://www.pocket-sundial.com/products/kala-sundial

    1. Roman numbers don’t have “0”, which means at midnight you can’t say if it is midnight or your battery is empty. And as the LED ring has 18 LEDs the M lights up at 00:00.
      As for the custom PCB: It seemed just a bit to much for 1 piece at least when I fount the 18 LED ring.
      With a custom board of 17 LEDs I would perhaps use 24:00 at midnight and the 00:01 for the next minute to avoid the “no lights at 00:00”

        1. Nice one. Of course that engraving needs to be backlit so you can see it in the dark. :-) But it would be nice to have the engraving and only the “it’s midnight” part backlit…

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