It turns out there's a handy Arduino library for time. And it will
ingest GPS or NTP, etc., as well as run off the internal clock.
One strategy, then, is:
Set the clock in the Arduino
then, periodically (once a minute or hour)
look up the date and time
calculate rate
So, periodically, one would need to reset both the analog clock AND the
Arduino clock to bring them back to proper alignment.
I suppose that periodically, one could compare number of ticks sent
with UTC + EOT offset and try to compensate (by dropping ticks or
adding them).
And then
t...@leapsecond.com said:
If your project works ok for the earth clock, the next step is a
jaw-dropping array of 8 (9) clocks in a JPL lobby showing the differently
ticking solar time for each planet. Use 24h clocks for best results. They
can be had from www.clockkit.com, an excellent source
On 1/19/14 1:51 PM, Tom Van Baak wrote:
So, periodically, one would need to reset both the analog clock AND the
Arduino clock to bring them back to proper alignment.
I suppose that periodically, one could compare number of ticks sent
with UTC + EOT offset and try to compensate (by dropping
So, do you run the whole thing off 12V (which is what I'm going to do)
and a float charged battery OR do you do something clever like detect
when power is failing and save it in NV storage, then when you come back
up, you send a bunch of clock ticks real fast to catch up.
Use a high-res
On 1/19/14 4:10 PM, Tom Van Baak wrote:
So, do you run the whole thing off 12V (which is what I'm going to do)
and a float charged battery OR do you do something clever like detect
when power is failing and save it in NV storage, then when you come back
up, you send a bunch of clock ticks real
Hi
Rather than calculating the ppm offset, calculate the number of ticks until you
drop (or add) one tick. Your output pps can only be offset from the input pps
by an integer number of ticks anyway. The next decision would be - how big a
tick can you get away with? For a wall clock, 100 ms is
The EOT code that I linked to (http://www.astronomycorner.net/games/analemma.c)
and am using is interesting because it appears to be applicable to other
planets. It has parameters like the orbit
obliquity/eccentricity/perihelion/year length that can be changed. It also
does not make
From: Jim Lux
[]
To be honest, one of the interesting challenges is dealing with power
failures in these kinds of systems. The Arduino is not a low power
device..(at least not in the AA battery for 2 years sense).
[]
___
Jim,
For low-power, long
