around the world, around the world

A project log for clock in hardware

as I work with people all over the globe, I need a simple way to tell their local time without hanging lots of clocks on my wall

rawerawe 08/06/2014 at 10:260 Comments

the clockwork consists of the drive (coil and small gear with attached magnet on the right) and the clockwork itself on the left:

The three main gears are connected with two additional gears. Divider factor is "60" for each step, resulting in seconds, minutes (runs at 1/60 speed of the seconds pointer) and hours (runs at 1/60 speed of the minutes pointer):

the drive mechanism is really simple: 32kHz quartz, electromagnet, "logic" blob:

Which of the quartz pins is XTAL in and out can be figured out by probing with an oscilloscope: The pin with strong signal is XTAL out, the other one with a weak (or no signal) is XTAL in (input impedance of scope stops the oscillator).

Test driving the circuit with a function generator works best with AC coupled clock signal (there is already an internal resistor which drags the input to threshold between hi/lo logic levels:

With a bit of modification...

...and glue, the "world" fits on the hours pointer:


Around the world, around the world
Around the world, around the world
Around the world, around the world
Around the world, around the world 
(daft punk)

I'll leave it like this for now, maybe the outer ring will go on the white plastic frame later. It is possible to use standard acrylic paint for this (tested on another RUSH clock):

This clock stuff is a perfect excuse to upgrade my test gear and order an EEVBlog µCurrent GOLD, lets see how long the shipping to Germany takes...