[time-nuts] Power monitoring
hmurray at megapathdsl.net
Thu Apr 17 14:10:11 EDT 2008
My power went out the other day. That reminded me that I've always been
slightly curious about that area.
Are there any not-expensive boxes made for this? Or something that shows up
on eBay occasionally?
If I was doing it myself, I'd start with a low power (quiet) PC and a UPS.
Then I'd have a platform that could monitor other things too, like
Step 0 is just to measure when power is/isn't there.
I assume the UPS has a signal for that.
Step 1 is to measure the voltage.
This takes an A/D. The standard PC audio input might be appropriate.
I'd probably use an AC wall-wart transformer for isolation and a couple of
resistors to get down to a reasonable voltage.
Step 2 is to catch dips and spikes.
That's just software behind the A/D. (assuming the A/D is fast enough)
As long as I'm dreaming... Suppose I wanted to measure the power my whole
house is drawing. What's available along the lines of a current transformer
on the main lines? My first thought is that nobody does that (for homes) so
it's probably horribly expensive. On the other hand there is a lot of
interest in energy conservation these days so it might only be somewhat
These are my opinions, not necessarily my employer's. I hate spam.
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