The Original Crap Clock

After all this time it is finally here, the Crap Clock. Albeit a simplified version that is cheaper to build and doesn’t have the added bloat of a battery charger, boost circuitry and a zero voltage on/off switch. It still maintains the main functions though. Beware, I have not printed this variety so cannot 100% guarantee you won’t need a bodge wire or two. It comes with no license, do what you like with it, but if you can give me credit please do. Also, a lot of YouTube viewers helped me with this so it is as much theirs as it is mine, so give something back to the community where you can.

It is my great pleasure to present to you the Original Crap Clock.



The Crap Clock is a clock running from a ATMEGA328 which drives 82  LEDs via a 74HC595 driving the rows and a TLC5940 sinking the current across the columns. As DS3231 keeps the time and can be kept running with the battery input terminals. The clock has several ‘modes’ to view the time, date, year, temperature and mirror modes for setting the time and date with the two buttons. The LEDs can be dimmed with the TLC5940 and the seconds display (Pink LEDs above) can be used to display a contextual letter alongside the mode the clock is in.

There are a couple of features I have not used or have taken out of the PCB. There are still pins for the inbuilt DS3231 alarm INT/SQW pin and a buzzer pin from the ATMEGA. Pin 10 is broken out for general use and there is also an analog pin available for a feature like a LDR to alter brightness.


Wanna see how I got here, this is a playlist of all the videos where I can remember talking about or designing the Crap Clock.

Eagle Files (includes Bill of materials) – Crap Clock Simplified – 110KB

Here is the Bill of materials – Google Sheet


It isn’t very good, nor is it all that pretty, basically perfect for the Crap Clock.

STL Files – Crap Clock Case – 56KB


It isn’t great of course but it is working and easy to modify, no idea how to make a library so this is all a bit of a train wreck.

Crap_Clock_v3 – 4KB Just normal code really but I wrote it in the Arduino IDE and used some libraries 🙂

You will need to upload this with a programmer, I used and Arduino as ISP.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.