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Metering solution


#1

Hi,
Is there any component which can help me in reading power consumption?


#2

No but funny we were just talking about adding it!


#3

Well, it does not mean that it is impossible.
As you might know power is calculated by the formula:

P = U * I

So, you will probably know U, since it’s your supply voltage.
Only thing that is left is I (amps).

To do this you can use one of these components, connect it to analog in (with a voltage divider, MAX 3.3V on analog in!), and let FEZ do the math.

-5 … +5 A
http://www.pololu.com/catalog/product/1185

-30 … +30A
http://www.pololu.com/catalog/product/1187


#4

Where do you want to measure power consumption? One appliance, whole house?

The sensors suggested by Robert are invasive, so be very careful when connecting them. Mains power can kill you!!

Other solution is to use non-invasive sensors like: http://tinyurl.com/3alrbnw (seeedstudio link)

or if it’s for whole house power measurement, get a kwh meter with a S0 output like: http://tinyurl.com/3yze2be (ebay link)


#5

Eric is right. My suggestion is for robotics use. (e.g. motor power consumption).

Since you did not give a usage example, together with the USBIZI chip, I suggested this solution.

For house solutions, make sure to use as safe sensors as possible, as suggested.


#6

I would seem cool to have that integrated with a relay component, and get both.


#7

Check this out: http://www.sensorsmag.com/sensors/electric-magnetic/measuring-current-with-imc-hall-effect-technology-786

See “Figure 5”

A datasheet can be found here:


#8

for home consumption reporting there are a couple of options, certainly the current clamp solutions are pretty reasonable in my view; there is in fact an aussie mob who have built a 6-input shield for arduino (see www.smartenergygroups.com SEGmeter) and I’ve been thinking about trying it on Fez, but I think that the 5v/3v3 difference in ADC will change the calibration a little. Not my highest priority project I’m afraid, since I have a commercial Efergy meter that I read data from to my PC periodically.

Here’s my ideal world view of this: similar to the SEGmeter, except that it’s a self contained shield using specific i2c or spi only, and has inbuilt ADCs for more than 6 inputs. That way I could monitor individually the power draw on things like the sewerage pump, pool pump, aircon, lights, oven etc, rather than just the efergy monitoring the 3 phases.


#9

Thanks everybody!!

Very interesting, I wanted to build something similar to smartenerygroup.


#10

Do you have a link to smartenergygroup ?


#11

The link was in the previous post (Brett’s post).

It’s http://www.smartenergygroups.com