Comments on: Wattcher, twittering Kill A Watt plans posted

By: draeath

draeath — Thu, 13 Jan 2011 20:24:18 +0000

Came back to try this… my Kill-A-Watt has a different board! The IC that he hooked into is absent! (among a few other minor looking changes).

Saaadneessss.

By: peter

peter — Tue, 14 Dec 2010 22:22:41 +0000

@frollard

over in the uk, because we have 240V, kettles usually linger around the 9 amp region, our standard cabling is 13A so any plug in the house can support 240*13 = 3120W, space heaters are 1.6-3kw here, so it’s quite possible that he has a 2.8Kw kettle if he’s in the uk (ours is 2.9Kw)

By: Chris Bergeron

Chris Bergeron — Mon, 14 Sep 2009 01:48:57 +0000

Most meters will pulse the infrared LED for each watt-hour of power being used. I have an Itron Centron on my house. I have a little more info about it on my blog:

http://chrisbergeron.com/?p=159

By: Anonymous

Anonymous — Fri, 27 Mar 2009 18:38:48 +0000

The standard costing 200$ mentioned on this page:
found via google
http://betonprojekt.info/tmp/iec%2062056-21.pdf

By: danny

danny — Wed, 28 Jan 2009 23:52:15 +0000

here’s another ‘count the number o times the power wheel goes round using a near object sensor’:

http://community.pachube.com/?q=node/65

has the added benefit of streaming data to pachube.com for graphing

By: Doug

Doug — Tue, 27 Jan 2009 23:19:17 +0000

@Winphreak; every home that’s on the grid has a device, that will let you measure how much power devices left on consume while. Simply read the power company’s meter before you leave and again when you come home.

By: ewertz

ewertz — Tue, 27 Jan 2009 14:11:56 +0000

@myself a more generic solution would be to get a monkey, teach him how to read LCDs and enter the data into a computer

but that’s not good engineering either

By: fluf1423

fluf1423 — Mon, 26 Jan 2009 20:39:39 +0000

http://www.sourceradix.com/ng.html

By: lekernel

lekernel — Mon, 26 Jan 2009 13:22:05 +0000

They use the same “supercap” technique in USB GSM modems… because the GSM transmitter operating at full power would require more current than what is available at the USB port.

Just for you to know that this hack is actually used in the industry :) although they use a smaller cap and probably some kind of rate throttling in case the capacitor discharges too much.

By: scdr

scdr — Mon, 26 Jan 2009 02:15:33 +0000

In terms of energy savings, one would have to include the energy cost from the manufacture and distribution of the Kill a watt meters. (i.e. if using several of these to monitor your energy usage, have save a lot in order to make up for the environmental cost of making the meters.)

One project that takes a simple approach to measuring overall usage is: http://www.bwired.nl/Stroom.asp

Have toyed with ideas of how to adapt that or the project on monitoring the water heater burner using a cell phone to reading an old electro-mechanical electricity meter.

By: jproach

jproach — Sun, 25 Jan 2009 21:54:10 +0000

@brett: looking at the instructions page, based off the pictures:

orange – voltage – AD0 – LM3902 pin 14
yellow – current – AD4 – LM3902 pin 1

By: Myself

Myself — Sun, 25 Jan 2009 21:46:03 +0000

A more generic solution would be some video OCR to read the display of any digital meter, and output the results over a standard API.

By: Brett_cgb

Brett_cgb — Sun, 25 Jan 2009 20:06:41 +0000

Interesting project. I’d long been curious what was inside the Kill-A-Watt with an idea to do something similar.

A quick question:
I can’t tell from the published schematics what the ORG and YEL wires tap into (ORG = Volt sense, YEL = Cur sense, or vice versa?) RED and BLK are clear (5V and Gnd, respectively).

By: rknobbe

rknobbe — Sun, 25 Jan 2009 15:55:54 +0000

@icebrain; here’s the archive version of an old site where a guy rigged up an optical reader that counted the number of times the wheel spins on his power meter. Don’t know if he’s moved on to a new provider…

http://web.archive.org/web/20060821104607/http://www.seanadams.com/pge/

By: IceBrain

IceBrain — Sun, 25 Jan 2009 15:50:25 +0000

@frollard: Yeah, I remember that, the meter has a infrared port (diode and led) for digital communication, but I don’t know which bytes I should send and how to decode the data (the protocol).

I could read the screen, but that would require a full computer, and I was planning to use an Arduino, and transmitting to the computer “on-demand”.