Cistercian Monk's cypher digital clock.

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The Cistercians, a Monk order from the 13th century, created a number cypher that was able to map from 0 to 9999 using a single digit.
This clock uses a 5x7 LED display to represent the Cistercian numbers to show the time using either the hh:mm format (00:00 to 23:59) or decimal time (0000 to 9999 intervals, work in progress).
The clock is also capable of representing the current day and month using a distinct pattern of dots on the matrix.

From Wikipedia article  The Cypher of the Monks:

The Cistercian numeral system, a numeral system that was used by the Cistercian order of monks in the 13th to 15th centuries of the Middle Ages, and has been used sporadically since then. It allowed writing numbers from 1 to 9999 as single compound characters.

The Cistercian numbers can be represented in a 5x7 dot matrix display, thus providing 4 digits to represent the time on a digital clock.

The Day and month can be represented using a distinguishable dot pattern

  • 1 × Arduino Nano Microcontroller board
  • 1 × DS3231 Clock and Timer ICs / Real-Time Clocks
  • 1 × SBM 4057 ASR 4 inch 5x7 led matrix, common cathode
  • 5 × 33 Ohms THT resistor, 1/4 Watt
  • 2 × B3F-4000 Switches and Relays / Switches

View all 6 components

  • Redesigning the code

    danjovic12/15/2022 at 11:45 0 comments

    Started to redesign the code using some of the lessons learned on the #Paganini Clock , specially the button de-bouncing and the state machine.

  • New buffered board

    danjovic08/07/2022 at 00:07 0 comments

    The single sided board present a problem to solder the display pins, as the solder side is under the display. That can be worked around with extra pads to solder bare wires that can be wrapped in the display pins.

    Nevertheless I planned to order the boards from a PCB shop then I have added a second possibility for assembling an ATMega328 directly on the PCB, instead of an Arduino nano, on the TOP layer. 

    The boards arrived recently

  • Buffered driver

    danjovic04/06/2022 at 00:33 0 comments

    Working on buffered display to boost the light level and allow the Monklock to be read comfortably under brighter environment. Also added an LDR to allow automatic brightness control.

    PCB is still single sided.

  • 07:07 AM

    danjovic07/09/2021 at 14:11 0 comments

    I woke up early today., 07:07 AM. One of the best features of this clock is that I can read the time on the other side of my bedroom without having to wear glasses.

    The multiplexing scheme used lits 1 led at a time. It is not appropriate for direct sunlight reading, but is perfectly adequate for interior lighting and glows awesomely when the lights are off.

    I have failed miserably to render a pair of images to represent the daylight readability, but I liked the result anyway, here you are!

  • Wooden base

    danjovic04/23/2021 at 15:14 0 comments

    Made a wooden base using dense wood upcycled from a scrapped bed.

    A hole and a groove were carved to provide enough room for the USB cable to bend. The hole is slightly out of center. Next time I should drill a guide hole first.

  • PCBs arrived

    danjovic04/17/2021 at 14:52 0 comments

    The PCBs acquired on a local manufacturer have arrived.

    The ground needed to be change to hatch and the layer Tdocu was unfortunately silk screened on the board which required me to scratch the paint over some pads on the RTC chip and resistors.

    I have tried out the components on the top layer, and they are ok.

    Can not say the same about the RTC library. That's one lesson we have to learn again and again: never trust 3rd party libraries - do a tryout first. At least it was possible to mount the module on the board despite the slant mounting headers.

    Rear view of the board

  • Setup mode demonstration

    danjovic03/08/2021 at 00:39 0 comments

    A short video demonstrating the setup mode.

  • First Working Version

    danjovic03/08/2021 at 00:01 0 comments

    First complete working version, can show the time, day, month and year.

    It can detect when the RTC is not preset or not responding (SDA was disconnected to take the picture)

View all 8 project logs

  • 1
    Modify the RTC module

    Change the 90 degree pin headers of the RTC module to straight pin headers, and solder them on the battery side.

View all instructions

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[this comment has been deleted]

danjovic wrote 03/25/2023 at 03:57 point


  Are you sure? yes | no

Darrell wrote 06/27/2021 at 07:51 point

This is a very cool project.  I had to write a Python program to convert 4 digit decimal numbers to Cistercian format.   dateTime() generates 3 cistercian numbers.  hhmm, mmdd, yyyy
The formatting is wrecked in this comment box but you can see what the console output looks like.

    o o o o o          o   o          o o o   
           o   o          o   o           o     
     o o o         o o o   o     o o o     
          o                o                 o     
   o o o   o           o   o     o o o     
        o o              o   o            o     
        o                 o   o            o

You can view/copy/share my Python code here.

  Are you sure? yes | no

danjovic wrote 07/09/2021 at 13:32 point

Awesome!! Thank you Darrel!!

  Are you sure? yes | no

Ken Yap wrote 03/08/2021 at 01:31 point

Wow, that representation is so compact and arcane. 👍 Would make a good random alarm clock. Will be certainly be awake by the time one has worked it out. 😺

  Are you sure? yes | no

danjovic wrote 03/09/2021 at 20:42 point

Like the Einstein clock right? But doesn't take too long to start to reading the numbers naturally and indeed that was something that amazed me on the Cistercian numbering system.

  Are you sure? yes | no

Ken Yap wrote 03/09/2021 at 21:57 point

If you rotate the display 180° you would be able to read it from MSD to LSD, R to L though. Is that considered a blasphemous modification?

  Are you sure? yes | no

danjovic wrote 03/21/2021 at 02:12 point

Yes, rotating the display would turn me into an heretic, lol!

  Are you sure? yes | no

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