Shut up and take my money!


I was about to start a energy monitoring project and while doing some research I stumbled across this site.  So, I thought to my self "Self, why should I reinvent the wheel?  These guys seem to have it together already."  That being said I want to spend money but I'm not entirely sure what I need to get.

What I want to do is monitor all the basic stuff such as volts, amps, watts, and gather some daily data to throw into a spreadsheet.  Most importantly I want to look at real and apparent and Power Factor. 

This is where I'm a little confused.  I already have some Arduino Unos sitting about so I'd rather have a shield version.  I really don't need wireless right now but will in the future.  Of course a display will be helpful so I can actually see what's going on.  The only thing I know I won't need now or ever is the Internet connectivity/logging/web thing.  There's just no interest there.

In order to measure Power Factor I'll need a AC/AC 9v adapter but it appears all of those are for European plugs and voltages.  Since I'm in North America I guess I'll have to get one local???

With all that being said I currently have nothing except cash.  Help me turn that cash into a complete system.

Best regards,

The Dude

Robert Wall's picture

Re: Shut up and take my money!

How are you going to get the data into a spreadsheet? You need to accumulate the data somewhere, because there's very limited memory available in the Arduino-based modules unless you add some externally. This is where the Raspberry Pi and the (local) network comes into the picture. Otherwise you need to be physically connecting to wherever the memory is attached and extracting the data - manually.

Any AC adapter will work. The nominal output voltage should be 9 V ( you can change the voltage divider if needs be to accommodate a different voltage) but for accurate measurements you need to find one that gives you a relatively undistorted voltage output. This can be tricky, because most are designed as isolated power supplies where waveform fidelity is relatively unimportant.

There are a number of threads here discussing the US power system (which is totally confusing to me!) which you might like to look at.

ukmoose's picture

Re: Shut up and take my money!


1) EmonTX ( does the reading) -> If you want a shield choose the shield version emonTX-shield

2) You will need someway of storing the data to get your daily data which is where the emonbase comes in.

- you can use one that also holds the database (choose RRM12Pi- but you will need to also purchase a Raspberry Pi)

- you can host the database on a NAS box or on a PC ( the PC would really need to be on 24/7)  or use which is currently free. ( choose any of the other emonbase solutions either the Nanode or RFM12Pi would probably do) 

3) The display unit is the GLCD . Generally you want this somewhere else than by your electricity meter, so it it wireless.

As Robert says there are a number of threads about electricity monitoring in the US, which would be well worth a read. 

thedude's picture

Re: Shut up and take my money!

I plan on using a SD card shield with a 1 or 2 GB SD card to hold the data.  I realize it may require a bit of rewriting of the sketch

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