Open-source power monitoring

I’ve been interested in doing power monitoring on the house for a while, the TED 5000 unit seems neat and the Brultech ECM1240 monitor also seems pretty good.  Both are around $200, but both have drawbacks.  The TED only monitors mains, and while the Brultech can monitor around 5 branch circuits, it lacks the simplicity of a built-in webserver like the TED.  Most of the software developed by the company, at least, is Windows- oriented.  But I’ve found some neat other projects that might be fun.I started off at, and he’s got a pretty simple setup using an Arduino board, sending data to some nice flash charts.  I read an article on hackaday, and Roman, one of the TED guys, actually chimed in on the comments – the problem with the setup is that it doesn’t monitor voltage, so accuracy is not great.  (This gives me newfound respect for the TED guys, too!)  Reading further in the comments, I ended up at, which looks fascinating.  They have a couple versions, one of which monitors voltage in the house as well, so I assume the accuracy should be pretty good.

I’d really like to get one of these Arduino Duemilanove boards to play with – they’re about $30, and they have 5 analog inputs already, so in theory we could monitor 5 circuits w/o much trouble.  One downside is that the ADCs only have 1024 steps of resolution, so on the mains that comes out to roughly 25W steps.  However, it looks possible to connect a high resolution ADC to the Arduino w/o much trouble (right….) for the mains, and the lower res ADCs are probably sufficient for the lower power branch circuits.

Now if google powermeter could just open up their APIs so data could be uploaded to them, to make the graphing simple right off the bat.

OK do I really need another project?  :)  But this does look fun!

2 thoughts on “Open-source power monitoring

  1. I purchased a TED 5000 to measure my total power and the solar power separately. Unfortunately, it isn’t as advertised. I went back and forth with their support for a while and they even shipped me a new unit. But after turning off the breakers in the house probably 20 times, is started working. It worked for about a week and then stopped again. Every few days I would have to unplug and reset the main TED box. Eventually, I gave up and just pulled the whole system :(
    I’m glad that TED is trying to make monitoring cheaper, but they use Power Line Communication (pulses through the house’s power) and it has a hard time working through 2 different circuit boxes to communicate.
    Another serious disappointment with their system is with the wireless display. When I placed the display in the docking station, the back-light never turned off. So it was consuming more power than it needed to.

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