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Internet Power Meter

Earlier, I did another project that allowed me to get a fair estimate about the power consumed in my house. I would say it as fair estimate as the power measured was not in watts. Simply measure the current consumed and that is proportional to the power consumed.. as simple as it is!!

Please refer to my other projects on power meter: -

Home Power Meter

What is all about this "Internet Power meter"

Now that I can measure the power consumed in my house, I want to view the same any time, anywhere, and the best way is to connect the measurement over internet. Recently, I procured "Web Platform Board" and really liked it. But the problem is that in order to host a server on this board at my home, I need static IP and need to configure the router. Luckily, I came across two websites which can actually store my data and plot curves for me in real time: -

Coms or Pachube and
Google docs

In this page (project), I am going to explain about how I connected the board and feed data to the above websites.

Some examples of my current sensor output: -

The CT I connected to my house electrical wiring measures the signals very accurately right from the lightest load (about 20W of the oscilloscope) to the heaviest one (2KW of the water heater). Here are some scope captures along with the rms values: -

1 fluroscent lamp (36W), Vrms observed on scope = 184mV


3 fluroscent lamp (3 * 36W), Vrms observed on scope = 349mV

2 Ceiling fan (2 * 75W), Vrms observed on scope = 359mV

Almost no load (only oscilloscope load) (15W??), Vrms observed on scope = 107mV

1 Water heater (2000W, single biggest load and purely "resistive"), Vrms observed on scope = 6.32V (yes, it is volts!!)

Some random load (??W), Vrms observed on scope = 390mV

Block diagram of my "Internet power meter" (transmitter): -

Block diagram of my "Internet power meter" (receiver): -