EcoHomeLab September 2016 – “Build your own Home Energy Monitor system”

by Blog

Loaded with soldering irons, electronic components, tools and pure clean ready to go printed boards we got into our mission: build our own Home Energy Monitor systems.

Again, time goes by and I don't take into my blogging role, but everybody in CarbonCoop is nice and I don't get told off, for now 😉 My excuse this time is that I have lost my phone with the pictures of the session and it has taken me ages to collect some. But here I am.

In fact this time there is not that much to say, last EcoHomeLab was pure action. Loaded with soldering irons, resistors, capacitors and pure clean ready to go printed boards we met at Madlab and got into our mission: build our own Home Energy Monitor systems.

First a bit of intro

Super Trystan, the OpenEnergyMonitor team and John Cantor ( are developing a new HeatPumpMonitor. But clever as they are, this energy monitor has more than enough to be used as a general purpose Home Energy Monitor, it can measure Real Power, count pulses (for some electricity or gas meters) and monitor temperature and humidity. All of these happens connecting the sensors straight into the board. It is also possible to display all the information in emonGLCD and the data is uploaded via WiFi to allowing you to visualize it in many ways. On top of that there is an Android app to make checking your electricity use a one tap move of your fingers.

If you are already an OpenEnergyMonitor user and have some emonTx or emonTH installed, you can also add a RF module and use the monitor as a base station to send the data, as said before, to emonCMS.

The plan for this HeatPumpMonitor is to be sold as that: an already built monitor for heat pumps with no need for soldering anything. But the prototype is a through hole kit, and Trystan has allowed us access to it. It has the potential of being anything you want to make, add extra functionality or keep it to the basics.

The basics

Before putting our hands to work, Trystan did a presentation: a bit of the theory about how to measure power, what is apparent power and what real power, a general overview of the board, components, sensors, firmware upload process, etc.

Below is a picture of the kit, what we started with:


And this is how it looks like when you have finished:

For more info have a look here

And we did it

We were 9 people some of us with previous experience with OpenEnergyMonitor some other with no experience at all in electronics but all of us very enthusiastic about the process. Also not everybody was building, Sian was there to fix her temperature and humidity sensor and so she did with Trystan's help. It was also Dom's birthday and he kindly brought some drinks to share making the space even jollier.

Each of the builders got to a different stage, it's quite a lot to do in just a couple of hours. I don't know how many but some monitors were finished but not properly tested. I left my one with the firmware already uploaded but it was not only until I got home that I saw it working. And it does work!!

Next EcoHomeLab

As we keep saying, this session was just the beginning. Next one is on the 13th of October at Madlab at 5:30pm. The plan for the ones that didn't finish, well to finish it. For everybody to look into emonCMS and see what we can do with our data, probably set up the Android app, look at other applications of our energy monitors… ah and fix things too if they don't work.

If you didn't start building your HomeEnergyMonitor don't worry you can do it on the next session and have all the support you may need, but get in contact first as we will have to ask Trystan to bring you one kit. Send me an email (carlos at and I'll give you all the info you need.

Find the meetup page here

But that will not be all, Ben who also works in CarbonCoop (and you know from previous EcoHomeLabs) will do a presentation of his masters dissertation on the potential of battery storage in a smartgrid environment.

And the photos

Thanks Matt for uploading a photo album here. But to make this blog look cooler I add the pictures to it as well.

Bye and see you next week at EcoHomeLab.