[time-nuts] Adafruit Ultimate GPS timing message arrival times

Nick Sayer nsayer at kfu.com
Mon Aug 1 18:49:45 EDT 2016

> On Aug 1, 2016, at 9:33 AM, Chris Albertson <albertson.chris at gmail.com> wrote:
> In fact that would be a good experiment:  Put two clocks up on a large
> computer monitor and make one always tick some random number of
> milliseconds away from system time and the other always thick on the
> system time.  Then you click on the one you think is correct.  Can you
> do better than a 50/50 guess. Keep incl=reasing the error until the
> guesses are about 90% correct.   I bet you find you eyes are really
> bad.   You ears are a little better and you might notice 40 mS by
> listening to the "tick" sound

I’ve done something akin to this with my Crazy Clock movements.

The Vetinari clock works by stealing 100 ms from a fraction of the ticks until it’s gathered up enough to do a “double tick.” I wrote the firmware and I can’t tell which seconds are 100 ms off.

There’s also the “Whacky” firmware. It ticks on a random tenth of a second within each second. In practice, it’s far more subtle than I thought it would be. It’s only really obvious when it picks values far apart from their neighbors.

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