Open Source Energy Monitor

I first heard about the Open Source Energy Monitor from Alexander Bischoff at Open4Energy.  We've covered all sorts of home energy monitors, and through our coverage and our own experience we've been able to get a good feel for what works... and what doesn't.  It is my personal belief that home energy monitoring systems need to incorporating monitoring, data storage, and control (or at least an output to encourage a person to control).  It seems that the Open Energy Monitor has all of this and more.

From the Open Energy Monitor About Us Page:

This is a project to develop and build open source energy monitoring, control and analysis tools for energy efficiency and distributed renewable generation.

These technologies are at the heart of sustainable energy systems, monitoring and controlling how energy flows between the various parts of the system. These tasks can be achieved using a low cost, modular, open source microcontroller system known as an Arduino, powerful and flexible enough to form the basis of a wide range of systems.

PV installation monitors, solar hot water controllers, household energy monitors etc, can be assembled from a selection of modules linked together with an Arduino and configured using simple to use software libraries.

With the Open Energy Monitor, homeowners can monitor all sorts of energy inputs, analyze the data, and force outputs as a result of the data. The only downside: it requires active homeowner engagement, something the home energy monitoring field seems to lack (at least if the experience of Google Powermeter and Microsoft Hohm tells us anything). A schematic of what is possible can be seen below:

At the heart of the Open Energy Monitor is Arduino, "a tool for making computers that can sense and control more of the physical world than your desktop computer. It's an open-source physical computing platform based on a simple microcontroller board, and a development environment for writing software for the board."  I actually received a coupon from RadioShack for some Arduino boards about a week ago, before I had even heard of the Open Energy Monitor.

The founders of Open Energy Monitor, who are based in the UK, are also providing a kit to help those interested get started with open source energy monitoring called Megni.

I'm not sure if I have the time to spend on a project like this (I do have to research other emerging home energy topics you know), but I know there are many out there with home automation and energy monitoring as their hobby, and this sounds like a great fit.  I'll be interested to see what smart home communication protocols are being used with the Arduino controlled energy monitors.  I'm guessing Zigbee wireless will be the most popular, as it is also an open source protocol.  Arduino already has a page on communicating over Zigbee.

I can't wait to see systems that are developed to help homeowners live more sustainably, please share yours with us (!

If you like this post, you'll also like our post on DIY Energy Monitoring!

enjoyed our post? let others know: 


I built my own home energy monitor based on the above plans a year or so ago; in fact I helped tweak the code for a bit more accuracy. Following the plans is not terribly difficult; there are actually very few parts required, and it made me wonder why some of the commercial offerings are as expensive as they are. The hardware just isn't that complicated. If you have a little hacking aptitude and you feel safe / careful enough opening your circuit panel to put the current transformers in place, I'd say give it a shot.
This is all fascinating if one only new the basic question; what, exactly are you trying to do? What is it for? Controlling what? Wind generators? Water generators? Solar cells? Al.
ckmapawatt's picture
That's the can monitor and control anything you want. Whether it is <a href="" rel="nofollow">wind power generation</a>, <a href="" rel="nofollow">micro-hydro</a>, <a href="" rel="nofollow">solar pv</a> or <a href="" rel="nofollow">solar thermal</a>, etc. For instance, say you had a micro-hydro system, and you only wanted the generator to run when the pond was above a certain level. You could take an input from the generator to measure power generated, and you could also use a level sensor to measure the level of the pond. If it dips below a certain level, you could shut a valve or stop the generator by forcing an output from the controller.
I think the original project eventually turned into this: And that one is for monitoring your home's electricity usage at the utility feed. But Chris is right; the vision - and to a fair degree, the implementation - is to be able to monitor most anything. The latest version of input module like can do temp sensors, pulse inputs (from gas or water meters), etc.
Also, once you have your own device and easy access to the data, it opens up all kinds of possibilities for reporting, analyzing, graphing, etc. I am sending my electrical usage to,, and, as well as a private page on my home server to see power minute by minute, and I'm storing it all in a database. Not everyone would want all that, but having the freedom to do as you wish with the information is invaluable, IMHO.
Hi I did a mini version of the idea which can be found here;video_id=TunjEe3Z3eM

Post new comment

Subscribe to Comments for "Open Source Energy Monitor"