WARNING: This design appears to be potentially dangerous. Utmost care should be taken, and ideally professional advice sought, before attempting to construct this item. Moderator (RW)
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Note from maker of "shield": Correct, do not build this if you dont understad the risks. I personally will run the Pi over WLAN, but that still doesn't take all the risks away. If broader interest for this "shield" I will fix a safer version, no problem. For now v1.0 is quick and dirty and focus is on power measurement capabilities of the ADE7878A.
I made this module as a bolt on (shield) to RPI B+
I logged my energy before via an optical sensor to the meter supplied by the power company , but wanted to see this now on a phase level, that's why I developed this. The Optical sensor giving kWh aggregated will be kept for calibration and aggregated power. I log every minute to an mysql server and via another program I can draw curves for any period of time I have collected data for. This includes also a lot of other parameters like temperature etc.
It's using the Analog Devices ADE7878A for Polyphase Multifunction Energy Metering.
The ADE7878A is high accuracy, 3-phase electrical energy measurement IC with serial interfaces and three flexible pulse outputs. The device incorporate second-order Σ-Δ analog-to-digital converters (ADCs), a digital integrator, reference circuitry, and all signal processing required to perform total (fundamental and harmonic) active, reactive and apparent energy measurement and rms calculations.
Board also contains 3 ports for 1-Wire via DS2484 and a RTC using the DS3232M with battery backup. One ID-EEprom according to RPI B+ spec for shield identification.
Schematic. v1.1 File:ADE7878A V1.1.pdf
Design is now up and running.
I have source code in C++