Homemade Kill-A-Watt

[jonnyGURU]

http://enerjar.net/

Thoughts?

[Travis]

I'm trying to make one myself using an MCU.

[Super Nade]

If the parts don't cost too much, I can whip up a PCB and test it.

[madmat]

Interesting concept although I can think of better housings than a glass jar. Something a wee bit less breakable.

[jonnyGURU]

Yeah.. I think they were going for the insulating properties of glass there. :D

[madmat]

Ah, well... plastic's as near to an equal isolator as you can get to glass and is (generally) far less fragile. Hell, Bakelite is less fragile although I dunno where you'd find commercially produced blank Bakelite project boxes.

[Super Nade]

Can somebody point me to IC#2 (the big one)? Can't find it on digikey..

[jonnyGURU]

Hobby Engineering: http://www.hobbyengineering.com/H2130.html

3 for $16 on eBay: http://cgi.ebay.com/3-pcs-DIP-PIC16F877A-PIC-Microcontroller-MICROCHIP_W0QQitemZ350064469167QQcmdZViewItem

[Jedi2155]

Looks interesting...if only I didn't already buy my Kill-a-watt :(.

[davidhammock200]

Looks interesting...if only I didn't already buy my Kill-a-watt :(.It would have been interesting to compare them & see just how far off they are especially with some Active PFC PSU's!:(

[cypherpunks]

It's a micrcontroller (http://focus.ti.com/docs/prod/folders/print/msp430fe423a.html) designed for energy metering. It samples V, A, and VxA at 4096 Hz, and is targeted at utilities who lose money if it measures inaccurately (bills or lawsuits, depending) so it shouldn't have trouble with funny current waveforms.

It also includes a precision reference and LCD driver. (Another variant is the MSP430FE42x2 (http://focus.ti.com/docs/prod/folders/print/msp430fe4232.html).)

There's an application note Implementing an Electronic Watt-Hour Meter with the MSP430FE42x Devices (http://focus.ti.com/general/docs/techdocsabstract.tsp?abstractName=slaa203b) that gives schematic, PCB layout, parts list, and software listings.

That should be enough to get someone started.