Mick decided to build Vetinari’s clock based on WaitingForFridays project. Lord Vetinari, from the Discworld book series, has a clock in his office that is designed to make his visitors feel uncomfortable by having the second hand move at irregular intervals while still keeping exact time.
The erratic second hand in Mick’s project is driven by microcontroller that bypasses the quartz crystal signal. Check out a video of the original project below.
Via the forum.
Tiny heads-up – the YouTube link is a bit broken (it got appended to the post’s URL).
The Youtube link is broken. It is missing the http:// part so the browser thinks it is part of dangerousprototypes.com
Interesting build and idea. A future modification or enhancement would be to see if you could get it to run off the 1.5V AA that the clock normally uses. TI have an app note for using a charge pump IC to get 3V from 1.5V. The app note is for their MSP430 uCs but the circuit is applicable for all uCs as there is just a single GPIO required to toggle a low power mode. You can actually completely ignore the low power mode signal pin if you don’t mind the time lag due to the charge pump needing to detect that you need more current for a specific task.
TI, Maxim, and Linear all have a variety of charge pump chips to make this easy, and Mouser seems to carry them. The MAX1797 will run from as little as 0.7 V input, although it does require an inductor.
Thanks for the heads up, fixed now
or use an MSP430L092
Nice!