On Mon, 11 Mar 2013, rickman wrote:

Yes, this is actually a demo to illustrate how low power an FPGA can be. An
FPGA will run both the clock and the receiver and use power from the
environment rather than batteries.

But this is all relative. My first "atomic clock" ran on the same set of
AA batteries for five or six year, and the second set is now four years
old. The Centrios "atomic" wall clock (digital) uses one AA battery, I'm
not sure how long that's been in. My watch is a Casio Waveceptor, 3 or 4
years old, which has a solar cell to refresh the battery and it's never
been less than fully charged.

Fice or six years seems almost as good as 'shelf life" and while I had a
small LCD clock (not "atomic") that seemed to run a long time on an AA
cell, I'm not sure it was all that lower current than the 'atomic clock".

I'm more impressed by the clock running off 1.5v than that the batteries
last reasonably long.

These things are amazing, considering the effort people used to put into
making WWVB receivers, admittedly the "atomic clock" craze has very much
benefitted from the power increase at the station.

I do orient them, but here in Montreal it's the rare night that they don't
sync up, and I don't think since I've had more than one that they all miss
the sync.

Michael