Kirikou: an open electricity monitor

Hello everyone,

This is my first contribution to this blog after months of reading it :)

I am Amin, I study a Bsc. of "Environmental and Resource Management" at the BTU, and I am currently doing an internship at the technical department at Wagner und Co. Solartechnik in Marburg.

My main task in this internship is to dimension and design photovoltaic systems for our clients overseas, and I could not help but notice how pricy the existing monitoring solutions are: more than 400 euros for a box that monitors your inverter's production and makes the data available on the internet. So I started thinking about building a system that does that for a very "affordable" cost. And since I have caught the Arduino virus for quite some time (Wired magazine's fault), I started to think about making an Arduino-based photovoltaic plant monitor, this is how I found the open energy monitor initiative.

Months of browsing and thinking made this little idea grow in my head like a good cancer, and talking to people about it generated mostly positive feedback.

I am now determined to launch a commercial product (DIY-Drones business model, more or less) that is based on the open energy monitor. This device, which I name for the moment Kirikou, will monitor the mains AC that comes from the meter to the distribution box in each building, plus 5 to 20 sub-circuit consumers. It will not require the intervention of an electrician (clip CT's). It will send the data to Pachube or Google Charts via Wifi. And it will cost 200-240 euros per unit.

Quite an ambitious target I know, but with the help and support of the inventors, the community and some other people, I am confident that I can make it take off. Open source hardware businesses started to pop up like mushrooms the last years, and that's fantastic! It is only fair to share the knowledge about things, it is a win-win situation for everyone and I really hope to see many businesses based on the open energy monitor.

There are also some unconventional ways to get it started, like these sponsoring programs that help entrepreneurs get on their feet in the beginning. A very good friend sent me this link to the Zurich HUB fellowship, and I applied.

I thought it would be in the spirit of the competition to get a community involved, and I created this Ulule page (screenshot below) to raise 120 euros to build my electricity monitor based on the Blackwidow board.

I am really excited to start this adventure with the support of a community, I believe that we could develop and spread this together.

I believe the first step should be to get more organized and communicate more efficiently on the technical choices and so on.

Your feedback, comments, criticism is most welcome, you can also visit my blog if you want to know me better.

By the way, the verdict from the Zurich HUB will be announced on Dec 20th (in a few hours), please wish me good luck :)


Networked Arduino's

Back in August this year, Ken Boak, Suneil and I had a build session where we developed networking for Arduino's. The documentation page still in the making can be found here:

I added a build example using the network for my home energy monitoring system with examples for an ethernet enabled master unit, PV monitor slave and Solar Hot water controller + energy monitor. All that can be found here:

Networked Solar hot water controller, Solar PV monitor and Home Electricity monitor

PCB Experiments

Trystan and I have spend an enjoyable afternoon experimenting with making our own PCBs. From knowing nothing about the process in a few hours we had made our first PCB!

Trystan on Quality Control

The finished Etherent Arduino board drilled and ready for population 
For more details see:

Energy monitoring at the CAT - part 4

continues from part 3

Next Steps and the PV Lab project

With the pulse output kwh meters on all the renewable generators and un-interruptible loads connected up to the display server. The next step on the monitoring data acquisition side is to get detailed data from the 20kW PV roof array.

The PV Lab project

This is quite a big project with a lot of different measurements being made including energy measurements on the DC outputs of the panels and AC energy measurements on the outputs of 6 inverters and to research the effect of panel temperature on performance the temperature at multiple points under the array and the wind speed over the array.

Thankfully Glyn Hudson a good friend of mine, who has just graduated from doing electronic engineering at Warwick university is working with me on this and Suneil is also just about to join us this coming week, so we will have a good team on it!

Last week we spent quite a bit of time doing some further development on arduino based pulse counting, using low level port manipulation to read from multiple digital inputs at the same time and also much faster. We are just writing up about that at the moment.

Microgrid display next steps
We are also hoping to develop the public display software further. We want to make it easy to use, simple to setup and flexible enough to be used for home scale energy visualization to CAT scale energy visualisation. A downloadable energy monitoring content management system, like wordpress or drupal say but for energy... more to come on this soon

Thanks for reading the update!

Energy monitoring at the Center for Alternative Technology - part 3

continuing from part 2:

Monitoring hardware to public display database interface

Another aspect of the project that has been interesting and I have learned quite a bit from has been connecting the different monitoring hardware up to the display database, We are doing this via three routes:

1) Direct access to the SMA Inverters webbox via a cleaver bit of code Carlos has written. Carlos has kindly documented his work and put it up on the website here, have a look:

2) Via a JSON string fetched across the network from a script on the proprietary SCADA pulse counting system. With the JSON string being decoded and the data being inserted in the database via the method documented here:

3) For the pulse output meters: total grid import, chp generation and backup diesel generator that are located on a different part of site were there was no existing pulse counting hardware: I used an arduino to read the pulses and an ethernet shield to send a JSON string with the power and energy data to the public display server. I have documented the Arduino pulse counting here

Finding out about JSON strings was really useful. A JSON string is a string structure that allows you to send a variable key along with its value. It is possible to use this key to automatically register new devices by checking if the device already exists in the database with the same key and also send data from multiple devices in no particular order to the same script on the server.

Learning about and using pulse output kwh meters has also been very interesting. It is a nice way of monitoring large systems and there are pulse output meters for all sorts of measurement applications: water, gas etc. Many smart meters are pulse output meters, if they dont have the wired pulse output they probably have the flashing led output that you can bolt a sensor on to as many people are doing.

part 4: next steps and the PV lab project...