@Clarke: ...Do you have the voltage and current specs for each? I imagine they'll require more power than a microcontroller output could provide...
That's one of the problems in that you usually can't find any documentation for the meters. Also you often end up modifying them by removing shunt or series resistors. Also you have to be careful measuring the internal resistance -- in some cases you can "blow up" the meter using (trying to use) a multimeter to determine the resistance.
In some cases like a meter that's geared to to measuring say 10mA max, you could drive this directly from the MCU output -- but you also have to remember that the meter itself can generate negative voltages due to reverse/back EMF. Personally, I prefer to use the MCU output to drive a transistorm and have the transistor drive the meter -- all of this will be covered in my forthcoming blog.
Max, this is going to be an awesome project - one where I think everybody will get the juxtaposition of old and new tech.
I still think that making it "dead on" accurate using a GPS time source would be pretty cool - "I'll just sync my pocket watch with atomic clocks orbiting the earth, using my steam-punk analogue meter clock".
Maybe make the seconds tick inconsistently, but have it bang-on when the seconds hand goes from full scale back to zero.
Neat project! I've lived more in the digital realm than the analog, so I'm curious how you're planning to drive these meters. Do you have the voltage and current specs for each? I imagine they'll require more power than a microcontroller output could provide so I'll have to stay tuned for the next report to learn how you plan to do that.
How about doing the whole thing analog? Each meter can be driven from a timebase like an oscilloscope or analog computer. You can sync between them the same way the horizontal and vertical waveforms are synced in an analog TV, but with more stages. And then sync the whole thing to 50/60 Hz line frequency to keep accurate time.