As others have said, there is a problem with the minimum usable frequency to
make the motor turn, and there is a problem with inertia, which precludes using
separate sine periods to effect small turns. So the best answer is to run the
motor using normal AC, for 6 minutes every hour (or for 1 minute every 10
minutes). The infrequent starts and stops should minimize errors due to slip and
inertia. You may have to program some kind of offset into the code to account
for 'slip' when starting and stopping. The device may count too much or too
little depending on the mechanical damping of the inner parts (and this may
change over time as oil dries out etc).

I saw on your site that you implemented a clock using d'Arsonval analog meters,
and the wandering laser spot clock. Your web page does not say if you used a 
stepper or something else as a motor for the spot. I have these references from 
that time:

  http://www.piclist.com/techref/postbot.asp?
  by=time&id=piclist/2005/12/20/142136a&tgt=_top&key=25uA+and+pwm+&from=

  http://petertodd.ca/art/meter-clock/

(interestingly, your meter clock predates my idea in that thread by almost a
year ...)

Anyway, the source code for these projects is available on your site. Do you
plan to make the totalizer code available too ?

Peter P.


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