[time-nuts] Thanks for the suggestions!

Mark Amos mark.amos at toast.net
Fri Apr 13 13:48:35 EDT 2007


Time-nuts,

Some time ago, I asked the list a question about syncing a desk clock / wall clock to a 1pps signal and got 
lots of great suggestions. 

And based on one of these suggestions, I just finished hacking a little battery powered electric clock.  I 
disconnected the clock driver circuit from the driver coil of a little desk clock. I used the 1 PPS signal 
from an iLotus M12M translated up to TTL to drive a CMOS D flip-flop and then a couple of NAND gates to 
supply the drive current to the coil.  I powered it with a wall wart and a 7805 on a piece of perf board 
hot-glued to the back of the clock motor assembly.

It was great to see that second hand start ticking off the seconds. I set it this morning and it has stayed 
in sync with WWV and my GPSDO clock all morning. It's a geeky thrill to see that second hand advance with 
each tick of WWV and know that this cheap little plastic analog clock is keeping time based on signals 
received from atomic clocks in orbit... 

Next, a scope clock!  Then maybe something with cesium in it.

It's only a matter of time.

Mark
W8XR





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