[time-nuts] Mains Frequency -again

[Hal Murray]

> Perhaps one of the little openlog units from sparkfun, or one of the  clones
> would work for logging?

> https://www.sparkfun.com/products/13712 

The problem with things like that for monitoring the power line is that you 
want to keep collecting data while you analyze the data you have already 
collected.  (They are great for things with a limited time run such as the 
temperature on a mailed package or the elevation as you bike/ski up/down hills 
for a day.)

Another problem is that they don't have an accurate clock.  If it has a spare 
GPIO pin, you can use that to input time.

I'd use something like a Raspberry Pi, but that's partly because I'm familiar 
with them.  I setup the data capture to switch to a new file each day.  ssh in 
to set things up and/or poke around.  rsync or scp from a big PC to grab the 
data.

An alternative is 2 of the sparkfun devices.  Feed the same data to both of 
them.  Turn one off, grab the data from it, then turn it on again.  Later, do 
the same with the other one.  You can use the data from one to align the 2 
segments from the other across the gap.

Of course, once you get things going, you may need 2 PCs to cover the gap when 
you reboot the single PC.  But that doesn't cover gaps from when the power 
company goes out so maybe it's not worth the effort.



-- 
These are my opinions.  I hate spam.