[time-nuts] Mains Frequency -again

[Dan Kemppainen]

Hi Hal,

I won't argue there may be things to consider going down this path.

However, for a device such as Andy's that (as I understand) currently 
has no data logging this would be a very cheap ($4.29 ebay clone, $5.23 
16Gb Sandisk MicroSD) and easy option. Set it and forget it.

One could Output a timestamp or simply a 'sample number' in the serial 
data stream, swap SD cards to look at the data. Just concatenate files 
on the PC side for long term plots.

Throw the thing on an battery with float charger, and you easily survive 
power outages.

Certainly many ways it could be improved

I intended to wire one up as a serial port logger on a GPSDO. The GPSDO 
outputs data once a second continuously. The plan was to wire it up 
inside, and forget about it. A 32Gb card would give more than a decade 
of logging for under $20. (Assuming everything lasted that long, and no 
other issues popped up, etc.). Of course in the GPSDO stream there is an 
MJD timestamp, so that's not an issue.


Dan





On 2/25/2021 12:00 PM, time-nuts-request at lists.febo.com wrote:
> 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.