[Santa-rosa-pm] January Meeting (corrected)

Dan Lyke danlyke at flutterby.com
Tue Jan 29 08:43:38 PST 2008

On Tue, 29 Jan 2008 07:37:57 -0800 (PST)
Ron Wickersham <rjw at alembic.com> wrote:
> the next meeting is Tuesday night, 29 Jan 2008 19:30.

I just moved to Petaluma, so I want to start attending more than once
or twice a year, but, alas, tonight I'm flying out to Utah to meet with

However, at the last meeting I was at, Ron mentioned wanting to play a
bit with power management. I've done two things towards that end in the

I've talked a bunch with my dad about cheap circuits for current
measurement, and I've got a couple of ideas that are just waiting for
some time to prototype, mostly revolving around one leg of a 110v
circuit going through a ferrous ring, a couple of wraps of wire around
that ring feeding through a few Ohm resistor, and measuring the voltage
across the resistor. Right now hung up in the theory of trying to get
more than 10 bits out of the ADC on my microcontroller, because I'd
like to read milliwatts to the full load of a standard 15 (or even 20)
amp circuit.


A friend sent me a "BlueLine PowerCost Monitor"[1], a little device
that just clamps on to the outside of your power meter and reads the
physical dial (using something like an optical mouse sensor), and then
broadcasts that to a receiver box. I'd love it even more if I could get
the data out into a computer, but the impact of having a number in the
middle of the house that reflects how many lights we have on is already
being felt.

Tying all of this stuff to Perl is waiting on me getting my work
situation stabilized a little bit, but it's coming...


[1] http://www.bluelineinnovations.com/nlpower/powercost.html

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