On Sun, 24 Jun 2012 14:35:46 -0400, Jim Wilkins wrote:

"Winston" wrote in message
...
On Sat, 23 Jun 2012 23:05:14 -0700, mike wrote:
On 6/23/2012 9:35 PM, Winston wrote:

snip
For stuff that unplugs, a Kil-A-Watt meter is a cheap monitor. There's
also a device that clamps on the electric meter and reads either the
LED
or a rotating disk and wirelessly transmits real-time consumption
numbers. They have a computer interface, but it's too expensive for
my
taste and it looks like the utility vendors that planned to support it
have backed out. I think it was called Microsoft HOHM. Blueline
Innovations is the vendor, but it's also marketed under other names.

Usually the electric meters tell me all I need to know, but once when
they didn't I monitored the 240V line current with a clamp-on current
probe plugged into a Radio Shack multimeter that has an opto-isolated
serial data output.

The datalogging laptop is an old, nearly free 400 MHz Compaq Armada that
draws about 12W from the AC adapter (no battery), 7W when the LCD powers
down. That's low enough to run it remotely off a car battery. If it's
knocked off the folding chair or table onto the floor I haven't lost
much, though laptops are easy to strap down.

I think it would be nifty to come up with a power adapter
for the sound card input to log power as compensated for
power factor. Left channel, volts. Right channel amps.

--Winston