Creating a Cistercian Numeral Watch Face: A Step-by-Step Guide to the 15th Century Monastic Numerals

I recently discovered Cistercian numerals which can display the numbers 0-9,999 in a single image:

Examples from Wikipedia

My plan was to make a watch face displaying the time using these numerals, with the bottom line being the hours and the top line being the minutes.

Hubert Sablonnière’s: A clock based on Cistercian numerals

Programmer Hubert Sablonnière has an article A clock based on Cistercian numerals linked from the Wikipedia article that displays the Hours, Minutes and Seconds on seconds as separate symbols:

Time displayed in Cistercian Numerals with added colour scheme

I planned to do the same but displaying just the Hours and Minutes on one symbol on a digital wristwatch.

Choosing the hardware

Initially, I thought about building the hardware for a watch using an ESP32 or Pico board with an OLED display (I might still do this sometime to make a desk clock).

Then I discovered there is an Open Source watch called PineTime:

The PineTime smartwatch by Pine64

Coding a custom watch face

Perfect! The operating system is InfiniTime written c++. (there is also an alternative WaspOS written in Python). There is even a simulator so you can program the watch without having the watch. I’ve not really programmed much in c++ so it was a steep learning curve (with lots of advice and questions answered on the Pine64 discord). But eventually, I had a watch face displaying the time:

Next, I will order a physical watch and work out to compile the code to put it on a real device.

Also, I have to work out where and how to store my code (as a branch) so it doesn’t get over-written by any update to InfiniTime.

To be continued…