The Ghost in the Machine

Posted on September 30, 2014 by Gary Carruthers

Clink Street, London, 30th September 2014

More agonizing about power.

If you replace a watch battery, the watch forgets the time.  So you have to set it again.  Like all watchmakers, we try to make that as painless as possible.  But it would be nice to eliminate the problem entirely.

We accidentally found a solution.  Our watches have Bluetooth radios in them, and at top transmit, they need a hell of a lot of power in a short space of time. More than coin cell chemistry can generate.  So we put in a mighty big capacitor - we call it the flux capacitor - to be there when the circuit needed it.

Then technical Director Mike Plevey said something strange.  "That's spooky.  When I disconnect the battery, the watch keeps ticking for six or seven seconds." 

"That'll be the flux capacitor," I said.  But that night I couldn't sleep.  How long could you keep the timekeeping core going on that flux capacitor, if you really tried?  We measured it.  About a minute, as long as you suspend the hand movements until the battery is replaced.  Maybe two or three minutes in future models.

Take the back off one of our movements and you'll find a little push-button at the 3 or 9 o'clock position.  Press it, and the hands will stop, though it will continue to keep time.  Then change the battery.  If you do so within a minute, the hands will catch up and it will continue as if nothing had ever happened.  Correct time, perpetual calendar, daylight saving, leap seconds, the works.

We filed a patent on that today.

Pictured:  The Police's album cover, The Ghost In The Machine.

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