Tracking houshold electric consumption

[mzypt]

We have pretty big electicbills and I would like to track electric consumption to find out why. I have few ideas how to do this. First I need to pick current from maincable using hall effect sensor or inductive coil. Then the current information needs to be converted to voltage and feed to PC via data logger.
So what I need is:
1. Design ideas for current sensor, schematics would be nice
2. Data logger. Maybe PIC based A/D converter with serial or USB interface to connect to PC
3. PC logging software which reads data from logger and displays a graph on PC online.

Thanks

 

[VSMVDD]

why all this logging

you need to turn everything off and check your next door neighbours arent blagging heat from you and yours

next go round each room and calculate its max mins in use

1kwhr = 1kw for 1 hour

 

[mzypt]

Well it's not just logging, I think it would be quite interesting project to see the daily consumption as graph on screen.

 

[MAXPAYNE]

Check EPE May issue...

 

[madhouse]

Curiously - I have a practical application for this idea. We have a farm, where there is one outbuilding used twice a week for meetings (summer and winter), a workshop that is used by a part time mechanic, a boarding dog kennels for up to six and a house that is split into two flats. The whole lot is powered from a three phase metered supply, and generates one large bill!

Splitting it up and working out who of the four parties actually uses what would allow much fairer charging for services, as the "switch it on and watch the meter" approach will never work! It would also be a big stress relief in my life....

I've considered the idea of trying to measure power usage via inductive means, but have not yet come across anything practical and economical enough for domestic use..... Home built data loggers are second nature to me, but it's an accurate measurement circuit that stops me in my tracks....

 

[mzypt]

I bought a 4 channel datalogger. Dataloggers inputs are DC voltage so I built an AC current to DC voltage converter using opamps, resistors and capacitors. I pick the current with inductive coil around main cable in .So far the circuit is not very accurate so maybe I need to try AD536 or similar. But I have proofed that it this system can be used to track elecrtic consumption. When I switch lights on I can see it from laptops graph and by calculating the mean value of data - I have the overall consumption.