OpenEnergyMonitor

Community Energy Plan maker

2012-01-28T03:44:00.000-08:00

Over the last year Glyn Hudson, Bethan Gritten and I have been running a community energy project with our local sustainability group Ecobro in the Penrhyndeudraeth area of North Wales. The aim of the project is to create a comprehensive snapshot of our current energy use as a group that we can then use as a solid foundation for creating a sustainable energy action plan.

As part of the project we have installed 20 openenergymonitor energy monitors and have also developed for the project a community energy auditing and plan making application which is what this blog post is about.

This is how the application works:

1) Fill out a single household energy audit, compare how your energy picture compares to the average UK household energy use and how it relates to the Centre for Alternative Technology Zero Carbon Britain 2030 energy scenario:

2) Aggregate data from each household to create a group view:

3) Explore how group scenario is built up of individual households contribution:

4) Explore future energy scenarios, see the effect of switching to electric cars, heatpumps etc on real household data from your group:

5) In the next version, see effect of energy efficiency measures, insulation, draft-proofing and see the cost and payback details of scenarios including a comparison of different measures by sustainable energy % increase impact per £.

The idea is that through this process we can help bring focus to areas and solutions that can have most impact and also give a tangible reference of progress so that milestones can be celebrated when achieved.

The application is largely inspired by David Mackay's book Sustainable Energy Without the Hot Air (free to read online) as you can see from the use of the energy stacks. The aim is also very much about creating a tool that helps to create sustainable energy plans that add up and in the spirit of openenergymonitor and David Mackay's book the application is open source.

Download the source from github: https://github.com/openenergymonitor/CommunityEnergyPlanMaker

Try it out:

http://vis.openenergymonitor.org/cepm/

If you would like to help with development that would be great, please get in contact / send us github pull requests. If your doing a community energy plan making project and would like to use this tool, please do and let us know how your using it.

University campus energy monitoring in France

2012-01-18T06:44:00.000-08:00

Hello, my name is Baptiste Gaultier. When I started working on the project of monitoring the energy consumption of Telecom Bretagne (an engineering school in Brittany, France), I was looking for products which can measure, store, and track the energy consumption data of a typical university campus.

After spending some time researching the available solutions, I found a lot of expensive proprietary products and a project you may have heard of, called openenergymonitor. This project provides a very powerful, web-connected energy monitoring system, and the best part is that it is open-source !

I started to work on top of emonTx and emoncms and here are some new features I added to emoncms (the new hardware features will be addressed in a future blog post) :

Map widget : allows you to see a map with all the sensors used for energy monitoring
Device manager : provides an easy way to add devices on the map widget
Node information widget : allows you to see all information (hostname, IP addresses, device type, power measured...) of a monitoring node

Screenshots

Dashboard with my university campus map

Device manager tab

We have made some progress, but we have still a lot of work to do before our goals are met, most notably:

Tagging and renaming the devices
Displaying the energy chart when clicking on a node
Drag and drop node positioning on a map (device manager)
Node filtering (depending on power consumption for instance)
How to use the map widget (documentation)

The code has been released on github (I forked couple of days ago) : https://github.com/bgaultier/emoncms3/tree/devicemanager

The entire team working on the project at Telecom Bretagne is convinced of the great quality of the openenergymonitor project and we hope our work may be useful in any way.

Cheers !

emonGLCD - getting time for the internet

2012-01-17T03:36:00.000-08:00

The emonGLCD is an open-hardware wireless graphical LCD display based on the ATmega328 microcontroller and is Arduino compatible.

The emonGLCD works very well as a real-time living room energy monitoring display. For the emonGLCD to calculate and display how much energy has been used on the current day it must know when the day begins and ends. Therefore it must know the current time.

The emonGLCD does not have a hardware RTC but its possible to implement a very accurate clock using the Jeelabs software RTC library and a web-connected Nanode RF. In the OpenEnergyMonitor end-to-end energy monitoring system the emonGLCD is used in conjunction with the emonTx (transmitter) and emonBase/NanodeRF which is used to post data on-line to emoncms.

When data is posted to the emoncms sever with a http request the sever response contains the current time of the sever. We have written a code example to extract this time from the http header reply and pass it via RFM12B wireless to the emonGLCD. The time on the emonGLCD is always correct. Both the emonGLCD and the NanodeRF receive power monitoring data from the emonTx

Demo video (single CT sensor system):

Demo video (solar PV monitor system):

Taking this a step further: when the emonGLCD receives the time from the NanodeRF the emonGLCD transmits back the current room temperature from it's on-board temperature sensor, then the NanodeRF posts this online to emoncms.

The Arduino sketch examples are up on github:

emonBase/NanodeRF:
https://github.com/openenergymonitor/NanodeRF/tree/master/NanodeRF_singleCT_RTCrelay_GLCDtemp

emonGLCD single CT:
https://github.com/openenergymonitor/EmonGLCD/tree/master/emonGLCD_singleCT_AutoTime_TempLog

emonGLCd solar PV: https://github.com/openenergymonitor/EmonGLCD/tree/master/emonGLCD_solarPV_type_1_and_2

Full web-connected home energy monitoring system

2012-01-14T06:02:00.000-08:00

The mission of the OpenEnergyMonitor project is to design and build and open-source energy monitoring and eventually control system. We would like this system to be work well for home energy monitoring systems but also be scalable. For more information see our newly updated project vision.

We are now at the stage were we have a fully functional end-to-end web-connected home energy monitoring system. We have recently written a full step-by-step build guide for the system. This build guide covers everything from assembling the electronics, uploading the Arduino firmware to setting the web dashboard.

The system consists of three wireless hardware units emonTx (transmitter), emonGLCD (display), emonBase (web-connected base station) and a powerful web-application emoncms.

We also have build guide/documentation for setting up a solar PV monitoring system using the same modules.

We are working towards opening an online shop to sell the hardware units (initially in kit form). Please fill in the interest form if your are interested.

Solar PV Monitoring

2011-12-26T10:07:00.000-08:00

I have just finished detailed documentation of an OpenEnergyMonitor Solar PV Monitor system see: http://openenergymonitor.org/emon/emontx/solarpv

The system monitors both generation and consumption and gives the user a clear indication of when their household electricity demands are being met by their solar PV array (green light on display) or when their not (red light on display). The display also shows how much electricity is currently being exported or imported.

The system is web connected, posting data to emoncms for logging and historical visualisation.

It has been suggested that installing a solar PV system results in decreased energy consumption and consumption pattern changes due to increased awareness of energy consumption verses generation. To enable these effects to take place the home owner needs generation level put into context with consumption level, in real-time. The OpenEnergyMonitor Solar PV monitoring system does just this, by simultaneously monitoring and displaying both generation and consumption. Most energy monitors currently available either monitor generation or consumption, not both.

The system is based on the emonTx, emonGLCD, emonBase and emoncms. All hardware and software are open-source and have been developed by OpenEnergyMonitor and contributors. At the beginning of 2012 we will be opening an online shop to sell these units in electronic kit form. If you are interested, please register your interest on the emonTx interest form, we will get back to you.

We would like to be able to offer the system pre-assembled in the future.

Please use the forums for discussion.

New emonTx PCB

2011-12-24T15:58:00.000-08:00

Introducing a new emonTx PCB design V2.1. No major changes just incremental improvements. Onwards and upwards!

The main changes are the addition of a footprint to enable a DS18B20 digital-temperature sensor to be soldered directly onto the board. The can be used instead of connecting an external DS128B20 temperature sensor using a 3.5mm jack.

The other change is the addition of a voltage select solder jumper for the IRQ pulse counting input which also doubles as a digital I/O port (Arduino Dig3). This solder jumper must be connected to either 3.3V (emonTx internal voltage) or 5V (if emonTx is powered via 5V usb). Routing 5V to the Vcc pin on this pulse IRQ port is useful when interfacing directly with pulse-output utility meters or controlling 5V relays. 3.3V works fine when using a TSL257 optical sensor to detect pulses from a pulse output LED.

Front

The other changes are purely aesthetic, a nice big Welsh dragon to recognise where Trystan and I are based up in the mountains of North Wales. We are very proud that our PCB's are designed and manufactured in the UK using an environmentally friendly process.

We have also added an area to note which frequency RFM12B modules has been soldered on, since once soldered on there is no way to telling! RFM12B frequency has become more important with the release of the NanodeRF which comes shipped with 868Mhz modules. OpenEnergyMonitor has in the past used 433Mhz modules; we now use modules of both frequencies. It's important to remember to use the correct length antenna for the frequency (details here) and set the correct frequency of the modules in the sketch.

Rear

We are on schedule to open an OpenEnergyMonitor online shop in the new year. If you're interested getting your hands on an emonTx then please fill in the interest form and we'll get back to you: emonTx interest form

open-hardware emonTx PCB designs are up on solderpad

The priority in the new year is to get custom encloses manufactured for the emonTx. Currently we have been drilling our own holes in a generic case for the connectors. If you can help us or have experience in designing and manufacturing electronic enclosures please get in touch.

Likewise if you have any ideas for improvements or new features for the emonTx then please start a discussion in the hardware section of the forums. We love to hear all ideas.

Merry Christmas everyone!

How to contribute on OpenEnergyMonitor dev + development plans

2011-12-19T15:46:00.000-08:00

If your wondering how best to get involved with OpenEnergyMonitor development here are a couple of thoughts and possible pointers.

First a few insights and ideas from an another open source project we follow: DIYdrones. Thanks to Amin Zayani for the heads up on these: [1] [2] [3]
In Chris Anderson of DIY drones's words, who we think has articulated it well:
“The best way to participate is to do something cool on your own and share it here. All of our code bases and hardware design files are open. If you see an opportunity to improve something, just do it, post it and then tell the community about what you've done. If it's good, people will use it, help improve it, and we'll get a sense of what you can do. That makes it much easier for us to figure out what your skills are and where you'd fit in best.”

If your looking for ideas here are a list of things we would like to do but no one is currently leading on them, Many of these problems are quite large, it would probably good to break them down into smaller sub projects. If you have a feature you would like to implement or would like to take the lead on any of the features below that would be really great, please post with your thoughts.

Appliance inference - infer from a single power feed of a house what each appliance uses and so providing a energy use by appliance breakdown.
PCB and casing for the 12 input pulse counter (a DIN rail and non din rail option)
Plug based energy monitor - for per appliance monitoring - an alternative method to appliance inference.
Larger monitoring PCB's: maybe 12 input CT?
3 phase monitoring sketch for emontx - quite a few people are asking for this so this would be really useful.
Develop a series of control modules, that extend the emon system into an open source monitoring and control system that can be used for domestic and industrial situations. Control modules could include:

multiple relay board (for dump load control, immertion heaters, pumps, lighting)
solenoid valve driver board for central heating control.
motor control
This emon monitoring and control system could link together by either a wireless bus say rfm12 or a wired bus (maybe rs485). The modules could be designed to fit in both DIN rail style casing or non-DIN rail casing.

Merge emonTx firmware examples into an Arduino library.

Short term goals

For a general overview here are the short term goals that are being worked on at the moment and in the very near future:

New casing design for emontx and emonbase
Transfer emonbase sketches over to EtherCard library
Compatibility of main sketches with Arduino 1.0
Complete watchdog addition
Emoncms development see feature plans and discussion page on forums.
Complete and publish energy audit software v1.0
Improve full emon system documentation.

This blogpost is repeated as a forum post here, lets discuss this on the forum as its a better place for it.

Thankyou
Trystan

How to move feed data between servers

2011-12-17T02:40:00.000-08:00

There is often a need to transfer large feed tables between different servers. Here is one way to do it via ssh that does not require downloading the data to a local machine. This makes it particularly fast especially if your local internet connection is relatively slow.

1) Login via ssh to the source server
ssh user@00.00.00.00 (source server ip)

2) Export feed table from source instance database
mysqldump -u username -p database feed_1 > feed_1.sql

3) Transfer feed table via ssh to destination instance server
tar -cjvf - feed_1.sql | ssh user@00.00.00.00 tar -xjf - -C /home/user (destination server ip)

4) Login via ssh to the destination server
ssh user@00.00.00.00 (destination server ip)

5) Import feed table into destination instance database
mysql -u root -p database < feed_1.sql

It would be great to have some kind of utility within emoncms that makes it possible to move large feed tables between emoncms instances efficiently and easily without having to use terminal and ssh. If you know of an efficient way of doing this, advice would be most welcome.

Open source and software as a service

2011-12-15T16:14:00.000-08:00

In addition to developing emoncms as an application that can be downloaded and installed on any server, interest willing, I would like to work towards offering emoncms as a service. So if you just want to build up your hardware and connect to a ready to go, maintained service with support, the option will be available to you.

One of the reasons I wanted to develop emoncms in the first place was that I was frustrated with fact that all available services where proprietary, I wanted to be able to download, install, modify, take part in development because I very much enjoy doing so and wanted to take part in collaborative innovation on important problems as Irving Wladawsky-Berger described so well in his post on the essence of open source which I blogged about last week.

As this article by mygnulinux.com and another article here by William Judd describe, there is a concern that as more an more of our applications move into the cloud and are run by organisations who adopt the proprietary software as a service business model we will loose the ground that we have gained in the open source software movement, there is also a complication to do with licensing.

There are however a great deal of advantages in having applications in the cloud many of which are also very beneficial for energy monitoring, such as: access to your data from any location and any device and possibilities that open up by using shared platforms.

The answer: cloud based software as a service does not have to be proprietary software, it can be open source and this opens up some really exciting opportunities.

So the idea is that the installed web application's code is placed on github or other code sharing location and is a mirror of the installation on the main server/servers. The service can be used as one would normally use a software service. However if you want to improve the code, modify, add something you can. You just need to fork the repository, do something cool, share it with the community and if its adoption is agreed it can be added to the service install. So this allows for taking part in development, for modification and improvement. It is a little more complicated than editing your own instance of a particular piece of software as changes need to be agreed on by those using the service as any changes will effect everyone, but this is not a prohibitive problem as there are systems that have already been worked out for determining what makes it into the final release in many large open source projects.

As mygnulinux.com and William Judd's articles explain, the other important problems in software as a service is: lock in, data ownership and licensing.

The first can be addressed by creating a comprehensive API that makes it possible to move data from one service to another or to a local installation if one desires to do so.

The second can be addressed through good policy by the service providers.

Licensing is important. The GPL up to and including v3 does not ensure openness for software as a service provided over a network as the requirement to release the source code and any modifications to that source code is only triggered when the software is distributed not when that program is run. This essentially as I understand turns the GPL into BSD like licence as there is no requirement for open sourcing when providing the software as a service across a network.

In response to this loophole the Free Software Foundation bought out another licence called the GPL Affero licence (AGPL) which essentially requires anyone providing a service using the software across a network to release the source code, the one additional provision over GPL v3 being:

“if you modify the Program, your modified version must prominently offer all users interacting with it remotely through a computer network (if your version supports such interaction) an opportunity to receive the Corresponding Source of your version by providing access to the Corresponding Source from a network server at no charge, through some standard or customary means of facilitating copying of software.”

In conclusion
It's possible to get the benefits of open source and the benefits of the cloud and software as a service platforms. I think its going to be exciting to explore this with emoncms.

The code for the latest version of emoncms is available on github: https://github.com/openenergymonitor/emoncms3
Its the exact same version as is deployed here: http://vis.openenergymonitor.org/emoncms3/
It is licensed under AGPL
A comprehensive API and tools for easy porting of data between instances is a core aim and will be an important part of continued feature development.
A template terms of service needs to be worked out and written.

Examples of open source software as a service
SugarCRM - a customer relationship management package (From the articles linked above)
Identi.ca - a micro-blogging service (From the articles linked above)
Thingspeak - internet of things application

Drop a comment below if you know of others that can be added to the list.

Nomination: Open source internet of things award

2011-12-10T14:20:00.001-08:00

Some exciting news, we have been nominated for the postscapes internet of things award:
http://postscapes.com/best-iot-open-source-project-2011

Its really great to see such a cross section of internet of things projects in the different categories, its well worth a look.

Essence of open source

2011-12-08T15:31:00.001-08:00

I recently came across this post by Irving Wladawsky-Berger where he described what he see's as the essence of open source:

“To me, open source is all about collaborative innovation, that is, working with people all over the world as a community to solve important problems.”

He explains how this collaborative innovation is nothing new, that:

"Collaborating with colleagues in your discipline is how you make progress, whether that discipline is physics, medicine, computer sciences or law." and that open source is essentially "a necessary precondition for, collaborative innovation involving software"

If we think about the scale of what has been achieved by this collaborative innovation involving software, the shared IT infrastructure, the internet and how it has changed and continues to change so much, its quite staggering.

Irving finishes by concluding that

"These are such important and complex problems, that only through the kind of collaboration made possible by open source software can we hope to attain the needed levels of innovation and progress."

I think that this is a useful way to view our work as openenergymonitor. The field that we are working in is sustainable energy which is full of important and complex problems and to paraphrase Irving: it will be through the same open approach in sustainable energy that we can hope to attain the needed levels of innovation and progress required.

AC-AC Adapters

2011-12-08T14:04:00.001-08:00

Today we have taken delivery of a load of AC-AC adapters in preparation for opening our online shop in the new year.

Using an AC-AC adapter with the emonTx to measure the AC voltage as well as a CT to measure current is is optional but it does increase accuracy by enabling real power measurements to be made. Using an emonTx with only a CT assumes RMS AC voltage to be fixed at a certain level (240V UK) and power factor to be equal to 1.

Real power measurements take into account the power factor of the AC circuit, inductive loads such as motors reduce the power factor thus giving an artificially higher apparent power reading. It is real power which you are billed for by the utility company. For more information on the differance between real and apparent power see AC power theory 1 and theory 2.

Using an AC-AC adapter also enables the direction of the current flow to be determined by providing a relative point of reference. Knowledge of the direction of current is crucial in monitoring a domestic solar PV systems when due to how the generated power from the solar PV is connected into the fuse box consumption cannot be monitored separately to generation. More on this to come...

Our tests have shown that typically the apparent power reading of in a domestic home is 5-20% higher than a real power reading. Although this seems like quite a difference in reality the purpose of domestic energy monitoring is to increase understanding of how energy is consumed in the home, apparent power readings are accurate enough for this. Also installing an AC-AC with the emonTx next to the utility meter can be tricky since there are often no power sockets to hand. This offset can also be calibrated out by calibrating the apparent power kWh/d readings against the readings from the utility meter.

Instantaneous real and apparent power readings of a domestic house AC circuit during the night, notice the fridge (compressor motor) reduces the PF thus reducing the real-power reading. Power in W is on the left axis, PF is on the right axis

As I mentioned at the beginning of the this post, we have just taken delivery of a load of AC-AC adapters, now time to test their quality.

The blue trace is the new adapter (pictures below) as you can see it's slightly better than the old one were were using (yellow trace), it is more like a perfect sine wave without the slight 'kink' in the middle that the old (yellow trace) adapter exhibits. Also the new model does not have the +2V offset, switching to the new model will require re-calibration of the emonTx in software.

The new AC-AC adapters. We have plenty in stock

Testing these AC-AC adapters also gave us the chance to test out our new DSO Quad mini-digital scope. Very nice!

Emoncms v3 beta

2011-12-07T14:06:00.001-08:00

It is time for another big update to emoncms, our openenergymonitor open source energy visualisation web application!

Over the last four and a half weeks several different threads have come together all centering around the idea of widgets and dashboards, last week it came to a head with an in your browser dashboard editor, it was clear that a major release was called for and so here it is emoncms version 3 in good time for the holidays.

It is also optimised (well nearly) for viewing on mobile devices and there is for the first time a hosted demo site available for trying it out, see the launch page the link and use notes.

Go to the Emoncms v3 beta launch page

Ubuntu podcast Interview

2011-11-24T08:43:00.001-08:00

A couple of weeks ago Laura Cowen and Tony Whitmore from Ubuntu UK podcast interviewed Trystan and myself at the HomeCamp 4 event in London.

A recording from the interview can be heard 27 min into this weeks edition of the podcast. Download it here: http://podcast.ubuntu-uk.org/2011/11/23/s04e20-run-to-the-hills/

Trystan and I have both use Ubuntu as our main operating systems for the last few years. We rate it highly and it keeps on getting better all the time. Its especially good for programming, we experience a lot less problems that windows users to when uploading code using the Arduino IDE.

Thanks a lot to Laura and Tony, I'v added the Ubuntu UK podcast to my RSS reader. Its a good listen.

HomeCamp4 Presentation Video

2011-11-11T06:27:00.001-08:00

Here's a video of our presentation at the HomeCamp 4 a few weeks ago. Many thanks to Debbie Davies and Mike the Bee for filming editing and uploading the video:

The videos of the other presentations from the event can be viewed here: http://lanyrd.com/2011/homecamp4/video/

See our previous blog post for a copy of our slides, their not too clear in the video.

Home Camp 4 presentation slides

2011-10-31T08:00:00.000-07:00

Trystan and I are currently traveling back to North Wales after a busy but enjoyable long weekend in London. We have been presenting the latest developments at OpenEnergyMonitor at the Open-Source Hardware Camp and Home Camp 4. It was awesome to meet lots interesting and enthusiastic people often with similar interests and working on similar projects to ourselves. Ian from dangerous prototypes will be posting some blog posts with more details from the event. Check out his blog and super cool open-source hardware development tools here See below for a copy of the slides we presented at the events. OpenEnergyMonitor Home Camp 4, London Oct2011

View more presentations from OpenEnergyMonitor

Home camp 4: London 29th-30th Oct

2011-10-21T12:00:00.000-07:00

Next weekend Trystan Lea and I (Glyn Hudson) will be down in London for Home Camp 4 'Hack the house' event. We will be presenting our end-to-end open-source web-connected energy monitoring system. If you live within traveling distance of London please come along, we would love to meet anyone who is involved or interested in open-source energy monitoring.

Home Camp is a series of un-conferences that brings together members of the technical community interested in using open systems to bring about a positive change in the way we use energy and appliances around the home.With ever-increasing energy prices, the race is on to develop ways to utilise smart technology to help offset domestic energy consumption and lower carbon footprints.

The event will be a combination of informal presentations on the Saturday and more 'hands on' making, hacking and tinkering on the Sunday. Trystan and I will be around on both days will be more than happy to help anyone build their own open-source energy monitoring system and deploy a server installation of emoncms. We will also have emonTx, emonBase and emonGLCD kits for sale at special prices.

When: 29th - 30th Oct

Where: Central London in the Center for Creative Collaboration

Cost: The event is now free! Registration is required on EventBrite

Who: See the event crowd sourcing page at Lanyrd

We will also be attending the Open Source Hardware Camp on Thursday 27th Oct at the same location (C4CC). This looks like it will also be a good event: http://oshug.org/event/oshcamp

See you there, Glyn.

Introducing Megni

2011-09-18T07:27:00.000-07:00

Now that the project is getting to the point where we almost have a complete open-source end-to-end web-connected energy monitoring system we are excited to be starting Megni a small business to provide kits and fully assembled units that aim to make it easier to get started with open-source energy monitoring.

Our core aims are to create:

Technology that encourages people to make and learn new skills.
Technology that helps us live within ecological limits.
Repairable, modifiable technology with a making story
We have been inspired by companies such as howies and Patagonia who combine their love of the outdoors with making clothing and equipment that help people enjoy the outdoors while also striving to produce those things in ways that causes no unnecessary harm. We would love to do something similar for technology.

The name Megni is made up of the welsh word for energy egni and the M part stands for monitoring or monitro in welsh. We are both welsh speakers and live in the mountains of Snowdonia in North Wales, UK.

As well as supplying OpenEnergyMonitor kits Megni will also offer custom energy monitoring and display services to businesses and organisations.

We are currently involved in a local community energy project which is keeping us busy for the next two months after which we are going to focus our efforts on getting an online shop up and running. In the mean time if your interested please see the buy section of the emontx documentation page.

Thanks for your continued support

Glyn Hudson and Trystan Lea

Nanode up in the mountains

2011-09-01T08:17:00.000-07:00

Glyn took the emonBase - nanode up Snowdon last week and got some nice pics. Combining two great things: open source green technology and the great outdoors!

Not all USB power supplies are created the same

2011-08-31T16:32:00.000-07:00

We recently ordered a load of cheap (~£1.50) USB power adapters such as this one and started to notice problems, nanode missing posts, rfm12 problems, emonGLCD crashes and so we ordered another two: one branded htc another ~£4 unbranded one which work well. The more expensive unbranded one specifically outlined that it was better quality in the ebay description.

Using the sampler program we can shed some more light on whats going on here. So first here is the cheap USB power supply:

As you can see a lot of noise, a standard deviation of 6.4.

With the unbranded more expensive adapter the standard deviation is reduced to 1.5!

The branded htc adapter is pretty similar at 1.6

USB power direct from a laptop, should be as good as it can get. A standard deviation of 1.2

Conclusion: its worth ensuring that the power adapter is a good quality one in order to get consistent performance from the hardware.

Nanode Applications weekend

2011-08-07T16:40:00.000-07:00

We have just come to the end of two great days in London at the nanode applications weekend, an un-conference style event at the Center for Creative Collaboration CC4C bringing people together to share and explore what can be done with the nanode an open-source Arduino like board with built in web connectivity developed by Ken Boak.

Over the weekend we presented our work on our end-to-end open-source energy monitoring system, comprising of the emonTx wireless transmitter unit, emoncms energy visualisation web-app and the emonGLCD display. Download a copy of our slides

As well as presenting we attended the event to hear about what other people are working on.

Here are a few of the highlights for us of the weekend:

Andrew Lindsay’s arduino sketch upload to nanode over Ethernet using TFTP. Fantastic, glimpse of the future? http://blog.thiseldo.co.uk/

Meeting Usman Haque from Pachube and seeing a demonstration video of augmented reality smartphone app for viewing sensor data http://apps.pachube.com/porthole/ . Maybe an interesting thing to try at the Center for Alternative Technology for overlaying say PV generation data on the PV panels.

Nick Boyle’s home monitoring with twitter and iphone notifications (partial documentation) - he gets a notification on his phone triggered by a certain energy event in his house!

Great to meet Franck Oxener a long time member on OpenEnergyMonitor who came all the way from the island of Texel, Northen Netherlands.

Interesting to hear about Christian Nold’s project using RFID tags attached to a complimentary local currency to explore social interactions through the movement of money, see: http://www.bijlmereuro.net/?lang=en

It was fantastic to meet lots of enthusiastic people all working on similar things. Since we are based in the mountains of North Wales this is not something we do on a regular basis. London can even be beautiful, on Saturday night we were treated to a wonderful rainbow display.

RFM12B Simple RF Transmission Demo

2011-08-07T15:08:00.000-07:00

We use the RFM12B wireless transceiver module as an integral part of our emonTx design. Here's a bit of general information about the module.

For a simple example of how to use transmit variables between a couple of RM12B modules see: https://github.com/openenergymonitor/RFM12B_Simple

http://www.hoperf.com/pro/rf/cob/RFM12B.htm

Project development

2011-07-12T14:12:00.000-07:00

As of today 285 people have signed up to be developers / contributors / users on OpenEnergyMonitor. This is fantastic, It's great to see the project expanding and becoming more collaborative. Activity on the forums has been steadily increasing, they are now a great place to discuss ideas, share problems and showcase what you have been working on.

Thank you to everyone who has signed up and contributed to the project.

A large number of people come with a large number of skills. We have encouraged people to write a little bit about themselves and their interest in the project when they sign up. Until now the only way to access this information was to click on each user individually in the developer section on the right hand side of the page. We now created a page to allow easy access to user profiles. This should make it easier for people with similar interests and working on similar projects to connect with each other and collaborate. The new page can be accessed by clicking on the little more link on the developers section of the right hand side of the page.

New user profile page

We have taken this a step further by installing a messaging system which will allow users to message each other directly. Just click on a users profile then 'send this user a message' link. The messaging system is very new, shiny and largely untested. Please report any problems.

New messaging system

I have been working improving the emonTx design and writing firmware examples.
We are working towards opening an online shop in the next few months...exciting times! In the meantime if you are keen to get your hands on an emonTx please contact me at glyn.hudson@openenergymonitor.org or message me using new OpenEnergyMonitor messaging system.

emonTx open-source wireless energy monitoring node

Trystan has been working on documentation and improving the code for emoncms to make it more modular, easier to understand and build upon.

Follow us on twitter http://twitter.com/openenergymon for all the latest developments from OpenEnergyMonitor labs.

Cheap AC transformers are no good

2011-06-24T04:15:00.000-07:00

The Open Energy Monitor uses an AC transformer as a voltage sensor, but the choice of this transformer can influence the accuracy of your monitor.

Jean Claude from JeeLabs (brilliant engineer BTW) investigated the difference between a bad and a good AC transformers and here are the results in images:

1) Bad quality transformer:

2)Better quality transformer:

You can read his complete post on his blog: JeeLabs Daily Weblog.

Twitter age

2011-06-12T04:04:00.000-07:00

OpenEnergyMonitor has joined the twitter age. Follow us to keep up with current developments, find out what we'r currently working on and join the in the conversation.

Follow @Openenergymon

How we envisage emonTx being used

2011-05-16T09:34:00.000-07:00

Many if you might be thinking what is our motivation behind the developments at OpenEnergyMonitor and how we see our designs being used.

Firstly we believe open-source is a better way of doing things, it is a way in which people can get involved in developing and making technology and build on the work of others. The OpenEnergyMonitor hardware builds upon the Arduino open-source micro-controller platform.

Taking the recently released emonTx as an example; we see the design being used in two ways:

For the enthusiast/hobbyist/maker/student: to be able to easily build an open-source monitoring system. They will assemble it themselves and customise it for their needs and hopefully develop some cool applications. To help them get going we will provide good documentation and code examples. Think along the lines of Arduino, Adafruit and JeeLabs. We hope that user developments will feed back to OpenEnergyMonitor. We are considering setting up an OpenEnergyMonitor online shop to sell the PCBs and kits. We have created a feedback form to try and gauge interest from the community.

For commercial use: The emonTx could be used in a professional large scale energy monitoring systems. Trystan Lea (founder of openenergymonitor) and I are in the process of setting up a business to offer energy monitoring services to organisations and businesses in our local area (see megni.co.uk) We are currently working on a community energy project which will also be a pilot test for our monitoring system see: http://ecobro.org/node/24. We are happy for and very much encourage other people to use our designs in a commercial setting as long as they attribute OpenEnergyMonitor and make any resulting designs available under the same open-source license; thus allowing others and us to benefit.

The same reasoning also applies to all other content on this site.

To read more about open-source at OpenEnergyMonitor please click here.

A prototype OpenEnergyMonitor monitoring system (emonTx + NanodeRF)
being exhibited at a recent sustainability event

emonTx feedback form

2011-05-15T12:27:00.000-07:00

Hello!

Here at OpenEnergyMonitor we are trying to decide how best to engage with interested parties and to promote exciting open-source development.

With our launch of emonTx we are considering opening an online shop to sell emonTx PCB's / kits.

We hope that making emonTx PCB's available at a reasonable cost will help people to quickly get an open-source energy monitor up and running. Leaving more time free for development.

I've created a feedback form on the website to try and gauge interest. Please could you take a few moments to fill it in.

Thanks a lot.

Meet the emonTx

2011-05-15T11:47:00.000-07:00

At OpenEnergyMonitor labs we have been working on designing a unit that makes building an open-source energy monitor easier. We wanted a unit that is cheap enough for a small home monitoring system yet powerful enough for a large system. We also wanted it to be easy to install and small enough to look pretty!

Two months ago Trystan announced a software milestone with the release of emoncms. Today marks another milestone for us, a hardware milestone with the release of emonTx.

emonTx stands for Energy-Monitoring-Transmitter. It's a small wireless energy monitoring node designed to take inputs from multiple CT sensors, optically from a pulse-output utility meter and from multiple one-wire temperature sensors. It is designed to be powered by 2x AA batteries or 5V USB.

Applications:

Electricity consumption monitoring
Renewable generation monitoring
Heatpump monitoring
Water and gas monitoring (from pulse output meter)
Temperature monitoring
Large scale monitoring - up to 26 emonTxs can potentially transmit to a single base station

emonTx PCB with bare minimum of components
for single channel CT monitoring

The unit has been designed to fit nicely in a case

Sneak peak inside

emonTx is based on the Atmega328 and is fully compatible with Arduino IDE.

The design is based on the JeeNodeV5 design, is fully open-source and is designed for easy expandability and compatability with JeeLabs shields.

The firmware is still in development, so far we have an emonTx monitoring a single CT channel and transmitting the data to a base station (Nanode + RFM12 breakout) where it is posted online to emoncms. We hope to release a beta version of the firmware in the next few weeks.

For more information see the emonTx documentation page.

Snowdonia build April 2011

2011-05-05T06:01:00.000-07:00

Now that the dust has settled, kitchen cleaned and toilet fixed it seems like a good time to look back on the last week.

Firstly, thanks to Ken Boak, Samuel Carlisle and Matthew Gaffen for making the trip up here to OpenEnergyMonitor HQ in North Wales for the 2nd ever Snowdonia build event. We had a great time and look forward to a reciprocal event in London.

The Team (minus Ken behind the camera)

The idea behind these build sessions is to get together a group of similar minded 'techies' together for a week, add in beer, food and plenty of enthusiasm and have some fun developing cool open-source technology.

Morning planning meeting in the sun

The common theme of last weeks development was sustainability and how open-source technology can be used to help people learn about and reduce their energy consumption and move to energy generation.

The Lab 2010

The Lab 2011

A rough wiki page has been made here to try and document the weeks developments.

Ken's great blog posts detail day by day developments:

Mats blog post: snowdonbuild

An interesting development for us at OpenEnergymonitor was Sam giving us a tutorial of how to use Github to share and keep track of open-source code. Over the coming months we hope to shift more of our code to the site. Click here to access the Github group. At present emoncms is the only fully implemented code on Github.

Snowdonia build 2

2011-04-28T16:20:00.000-07:00

6 days of open source sustainable technology development in the mountains of North Wales is under way!

We have Ken Boak, Sam Carlisle and Matt Gaffen all the way up from London hackspace. Suneil Tagore from Machynlleth and Glyn Hudson and myself from here.. Our plans are to work on OpenEnergyMonitor + Nanode applications, we will be updating via the wiki page here over the coming days.

Onawi - Open renewables

2011-04-24T05:28:00.000-07:00

Things are really moving fast in the open-source hardware world, and not just electronic hardware. What about an open-source wind turbine design?

Last week Trystan, Suniel and I met up with the team behind OWAWI Open Renewables. They are currently in the process of releasing open-source designs for medium size wind turbines.

This is a very exciting development in the world of open-source hardware. It has the potential to reduce the barriers to entry for wind turbine development, construction and maintenance all over the world.

Should we change to drupal based forums?

2011-04-01T01:14:00.000-07:00

Do you think it would be better to use forums integrated into the main openenergymonitor drupal based website?

This would mean the need for only one login to both comment on specific pages and use the forums. There has also been some extensive spam problems on the current forums which no doubt could be fixed but it could be easier just to use the drupal based forums..

I have set up a drupal based forum in the main site here:

http://openenergymonitor.org/emon/forum

Shall we try it?

Ken Boak's Nanode project

2011-03-31T01:05:00.000-07:00

Our friend Ken Boak has been working on an exciting project called Nanode:

a £20 Network Applications Node for remote sensing projects.

It is an arduino + ethernet + more board. At £20 it will really make a lot of difference to the affordability of networked sensing including very much home energy monitoring. Glyn is working on a battery powered energy monitoring transmitter module at the moment and if we then use the nanode as a base unit adding a small transceiver shield, we should have a very affordable internet enabled home energy monitor.

Check out Ken's blog posts about the Nanode here:

Nanode - It's a bit small isnt it
Nanode - Just make it
Applications for the Nanode

And the wiki space on the London hackspace wiki:

Nanode wiki

Ken is sending a couple of kits up this way soon and we are really looking forward to trying it out! I think there will also be Nanode kits available from Ken to buy in the not so distant future so watch this space!

Andrew Lindsay Ethernet Library
Using the updated ethernet library by Andrew Lindsay you can use this board as a server, a client and can even do DNS queries, check out Andrew Lindsay's work here:
Updated Arduino ENC28J60 Ethernet library available

The free charge controller project

2011-03-19T12:04:00.000-07:00

Another awesome project, a project to build an open source charge controller! it looks like a really neat bit of kit!

The free charge controller project

"The goal of this project is to design a charge controller with maximum power point tracking (MPPT). Maximum power point tracking allows a solar panel, wind turbine, etc to achieve maximum efficiency and deliver maximum power to a load. In this case, a load can be a battery, inverter, or the grid."

Cool projects: Humblefacture

2011-03-19T08:07:00.000-07:00

A really cool talk by Dominic Muren of Humblefactory about manufacturing and design:

"Modern manufacturing produces wondrous objects, in massive quantity, at a low price. But the costs to the environment, social stability, and economic justice are large, and often hidden. Small-scale, localized, clever manufacturing would minimize the ability for this cost hiding to continue. More importantly, local production gives the customer a bigger voice to dictate what they need and want out of products."

Dominic has a lot of interesting articles and analysis on his website humblefacture, very much worth a read:

The importance of {human} scale
DJs, Cloud Manufacturing, and the Need for Modular Open Hardware

SSG: A Framework For More Sustainable Electronics

Emoncms alpha is up!!

2011-03-12T15:32:00.000-08:00

As I mentioned in the last post Carlos, Suneil and I have been working on an energy visualisation web application, its a project that's been in development slowly for about half a year now but has only really started to take shape with quite a bit of work in the last month.

Today is a milestone because its got to a point where it is hopefully functional enough to be useful and so here it is a very much alpha release.

The name is emoncms for energy monitoring content management system. And the aim of the project is to develop an open source energy monitoring web app to make it easier to:

1) Understand our whole energy picture ( see screen below )

2) Understand the energy choices that we have

3) Keep track of our energy use and generation over time

Main features

Open-source, downloadable, customisable, deployable on any server in the same way as platforms such as drupal and wordpress etc are.

Build a whole energy picture by a mixture of manual entry categories and automatic monitoring categories. The whole energy picture intends to follow the approach of
David MacKay's book Sustainable Energy - without the hot air: linking through to the book and using primarily the kwh/d unit. It also takes a lot of inspiration from Saul Griffiths wattzon in terms of quite a few of the core features.

Energy categories are modules (in a similar way to drupal modules) making the application quite extendible, if there's an energy category that you'd like that is not available then you can develop and add it.

Renewable energy options suggestions, this could be really interesting, imagine every single type of renewable and efficiency option being related to energy use categories making it possible to quickly get a rough idea for better heating methods, energy saving by switching to an electric car and so on.

Connect up to energy monitoring equipment: Extensive and powerful data storage, processing, visualisation, sharing system for energy monitoring data (or any sensor data) from hardware energy monitoring systems. (see kwhd graph screen below)
Input processing: scale, offset, multiply with another input, log to feed, log to kwhd feed

You can download the alpha version and read more about it on the main emoncms development page here: emoncms dev

The current version is very much work in progress. There is very little error checking, input checking, security implemented. This is all to come. If you have expertise in these areas or would like to get involved in development of other parts of this you would be most welcome, just get in contact via comments on the emoncms dev page or via the forum.

Thanks a lot!

Sustainable Energy and OpenEnergyMonitor development

2011-03-04T09:45:00.000-08:00

I really first got interested in sustainability in 2005, I got involved with a group called the welsh youth forum on sustainable development and our main project at the time was on climate change. I remember one meeting where we where discussing what we would do. I remember thinking and suggesting back then that as sustainability requires a shift from our current carbon based use of energy over to renewable energy that a suitable project would be to measure our current use of energy as a group and see if we could make measurable progress towards both reduced use of energy and increased renewable energy.

Nothing came of the idea at that time as I didn't put the work in to make it happen, never-the-less the idea stayed in my mind and the idea of measuring energy so that we can receive feedback on our progress and make sure our actions are effective ultimately let to the starting of this project 4 years later. I also fancied the challenge of building the tools to do this myself as that would allow me to get at and use the data to make the analyses I wanted which was not possible with the household energy monitors available at the time. And it goes without saying that I also think that making these tools open-source would be awesome as open source is awesome.

While learning more about sustainability Suneil, Glyn and I came across a book called Sustainable Energy - without the hot air by David MacKay of Cambridge University: http://www.withouthotair.com/ which is a really enlightening book that we got excited about here. The book highlights an approach using quite straight forward maths for quantifying our use of energy in full and then calculating how much renewables we would require to provide that energy.

The result of the calculations is staggering in terms of the scale of the renewables required to provide our current energy consumption: We need country sized areas devoted to renewables to provide significant slices of our energy use. The main message of the book is that we need energy plans that add-up, we cant be anti wind, hydro, solar, nuclear etc etc and not in my back yard and at the same time expect enough energy to do everything we do at the moment and have a healthy biosphere.

Saul Griffiths great talk on energy comes to the same conclusions using much of the same approach, using Watts instead of kWh/d and applied to the world instead of the uk.

So where do we go from here?

I like the way Saul Griffiths puts it very clearly at the start of his talk:

“We've heard about climate change, energy plans... What you probably want to know is how do you fit in, how do you relate to energy. What you also really need are the right tools for making the right consumer choices so that your life can match with the outcome for the planet that you would like.”

Energy monitoring hardware is one part of the tool-set required and we have made good progress with this project on these: We now have an energy monitor for monitoring mains AC electricity use , a multiple input pulse counter to interface with many smart meters a DC energy monitor for microrenewables and a Solar hot water controller/monitor.

The other part to the tool-set is good visualisation of the monitored data so that it can be understood and related to our actions and aims. This can be divided into two parts: standalone displays and computer based visualisations. Glyn is currently working on a stand-alone energy display design and I'm working with Carlos and Suneil on a energy visualisation web application.

We hope the OpenEnergyMonitor tools can complement and build upon the work of David MacKay and Saul Griffiths making it easier to understand our energy use, understand the energy choices that we have and allow us to see and track the progress that we make.

In the next couple of posts I will introduce the energy visualisation web application that we are working on and also three initiative that are in the pipeline that make use of these tools: the CAT microgrid display project, the EcoBro community energy decent project and Megni an energy monitoring and energy visualisation business that Glyn and I have been working on setting up. There has been quite a bit going on recently I feel its time I sat down to update about it.

Sparkfun tutorial: Solder stenciling

2011-03-02T13:16:00.000-08:00

Sparkfun sometimes posts very useful tutorials on skills related to tinkering with electronics. This time they made a video tutorial on using a stencil to solder SMD components on a PCB. I find it quite useful, even for very small volumes (starting 5-10).

If you are not the lucky owner of a laser cutter, there are many websites that offer to produce the stencil for you like www.ohararp.com for reasonable prices.

Source

MakerBot's Bre Pettis on Entrepreneur.com

2011-03-02T12:31:00.000-08:00

After Limor Fried yesterday, another entrepreneur in the field or open source hardware is featured on Entrepreneur.com: MakerBot's CEO Bre Pettis.

For those who don't know Makerbot: it is a 3D printer that produces objects made of plastic from 3D files. You can order a kit and build your own, or optimize and change the machine.

(follow the link for the video)

I find the tips Bre gave in the video very helpful for people who plan to start an open source hardware business.

Source

Limor Fried:one of the most influential Women in Technology 2010

2011-03-01T19:16:00.000-08:00

She strikes again :) This time an entire article is dedicated to her on FastCompany.com.

I find this part really funny:

“They see how Adafruit is run, and say, ‘I’m gonna go off and start a company that makes 3-D printed robots!’” Fried says.

... because in our case, we thought we're gonna run off and start a company that makes energy monitors.

Source

The mighty Ladyada on Entrepreneur.com

2011-03-01T02:01:00.000-08:00

Ladyada talks about her open source hardware business. A must see for anyone who wants to jump in the field. I love the way she stresses that it is not just about running a business.

(follow the link for the full video)

The Innovators: Adafruit's Limor Fried

The founder of the New York kit company talks about innovation, R&D and customer feedback.

Source

Definition of open-source hardware

2011-02-10T15:54:00.000-08:00

The software and hardware of the OpenEnergyMonitor project are open-source.

Open-source software has been around for some time. The concept is simple to understand and relatively easy to implement. The source code with documentation is made available to all; usually a through a free online download.

Open-source hardware is a relatively new idea. Basically it entails the sharing of the hardware design (schematics, CAD files, documentation etc) so that the hardware can be reproduced and/or modified by someone else. Until now there has been no formal definition. A community derived official definition of open-source hardware is just been released:

http://www.adafruit.com/blog/2011/02/10/open-hardware-definition-1-0-released/

Logo ideas for open-source hardware. To be printed on PCB's etc.

Below is another (newly submitted) logo I found on the forum. I really like this one. I think it combines the best features of the best two designs above. The only problem I can see is the circles being mistaken for pads and drilled out while drilling the PCB!

A few tips from DIY Drones

2011-02-06T12:48:00.000-08:00

I visit regulary DIY Drones, and two posts lately captured my attention because they are directly related to our project:

Dronepedia: The first issue is the necessity of having a well done wiki for any Open Source project. A solid wiki would spare users a lot of time and many replicated discussions. I think it is time for the Open Energy Monitor to have a solid wiki, and the team here agrees on it. I guess we will roll it very soon. Needless to say, help is much appreciated.
DIY electronics warranties: A serious issue for the DIY movement businesses, and small electronics makers in general. Where does your liability stop, and where does users responsibility begin? As Anderson puts it in his post, it varies from one company to another, while they are committed to delivering a minimum level of customer and technical support, other companies estimate that starting the moment where you power the components on, their liability stops. It is quite paradoxal indeed. I invite you to read the linked post ans share with us your opinions in the comments

A business wants to see the light

2011-02-03T02:08:00.001-08:00

You may remember my last post on this blog. I was raising money to fund my prototype of an energy monitor connected to the cloud via WiFi. The crowdfundraising was a success (probably thanks to some of you), now that 95% of the components arrived I had the monitor assembled and the sketch running. A few technical problems are to be overcome (please check the forum and see if you can help), and the business plan is taking shape.

Yes, exactly: business plan :) Trystan, the other founders and myself would love to see a few small businesses based on the concept of open source hardware, in other words we would like to see some people making money with this system. Moreover, we would like to see a network of these businesses co-existing in a constructive symbiose to drive the wheel of development on a wide scale.

We are probably too much influenced with the amazing success story of the RepRap project, and so what? I personally believe there could be fantastic things evolving around the open energy monitor concept.

To start a business is a very hard task, definitely too much for one person, even if you work 24 hours you can not be good at both business development and product development, this is why I decided to get help from another person to sail this boat: I think with the help of one or two other persons we can launch a small but promising and ambitious startup that produces around 30-50 energy monitoring systems per month. My technical skills are modest, I can not pretend to be an engineer, this is why I will find the help of a technic freak priceless.

I posted this little ad on adafruit industries, it is not a job description, and can be part or full time, up to you. The most important is that if you show interest we can talk about it and see where we go from there.

A great talk by Saul Griffith on energy

2011-01-20T08:21:00.000-08:00

A fantastic video:

Can we make this kind of analysis and sustainable energy plan at the community-group scale?

It would be really exiting to integrate the electricity energy monitoring hardware directly into such tools so that the larger context of energy use is easy to see.

RF communication and wireless display

2011-01-13T04:55:00.000-08:00

How to use these RF modules to create a low-cost simplex link between two Arduinos

Example implementation of the RF modules to create a wireless energy display using the Nuelectronics 3310 LCD Arduino shield.

A battery powered wireless energy monitor sensor node.

2011-01-01T16:49:00.000-08:00

A battery powered wireless energy monitor sensor node in development:

Main features

1 CT input
2 Pulse inputs
Boost converter for efficient battery use
RF board connect

http://openenergymonitor.org/emon/node/115

Rearranging builds upon

2011-01-01T13:55:00.000-08:00

I made a start on rearranging the builds upon page, I'd like to elaborate on the different ideas that the project builds from:

sustainability
open source design
personal fabrication

and explore the larger open source sustainable technologies ecosystem that is out there.

PCB's

2011-01-01T13:51:00.000-08:00

A few more designs:

- mains ac module
- multiple input pulse counter
- baseboard
- barebones CT Pulse RF unit

+ some example module connection diagrams at the bottom:

http://openenergymonitor.org/emon/node/114

Next step is to order the components to test a few of these.

PCB Designs in development

2010-12-31T11:46:00.000-08:00

PCB Designs

The plan

Create a PCB's for each module that interconnect via standard 3-wire and 4-wire connectors. A PCB specifically for:

Mains AC v3 module
RTD Temperature sensing module
Relay module (may be able to use modules available for this)
multiple input pulse counter
Compatibility with the nuelectronics datalogging board.

Baseboards

Develop a baseboard that is an Arduino with normal shield headers but also with 3-wire and 4-wire connectors on the same PCB.

Develop a baseboard that is an Arduino with normal shield headers, 3-wire and 4-wire connectors and also tri-state buffer for master/slave network operation.

An barebones arduino with a CT or pulse input module and RF transmitter socket all in one.

Sampler 2.0

2010-12-21T01:54:00.001-08:00

I wrote this program a while back, its an update to the VISampler program. When building the energy monitor its sometimes useful to be able to see the AC Voltage and Current waveform that your monitoring. It puts my mind at rest to know that the circuit is doing what it should: no large noise or over voltage spikes.

Main features

Select arduino from USB port drop down list
Take samples at different sample rates
Select any analog input or multiple analog inputs
See a zoom-able, pan-able graph.
Get Mean and Standard deviation of sample

Download it here Sampler 2.0

Kirikou: an open electricity monitor

2010-12-19T16:40:00.000-08:00

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 :)

Amin

Networked Arduino's

2010-12-11T07:21:00.000-08:00

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:

http://openenergymonitor.org/emon/network

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

Temperature Sensing using DS18B20 Digital Sensors

2010-12-11T07:13:00.000-08:00

A tutorial by Glyn (Thanks Glyn!) on Temperature Sensing using DS18B20 Digital Sensors, These are really neat little sensors that can be stringed on to one bus line:

Temperature Sensing using DS18B20 Digital Sensors

Build a multiple input pulse counter

2010-12-11T07:03:00.000-08:00

A tutorial on how to build a 12-input pulse counter. Built for monitoring of large setups like the Center for Alternative Technology microgrid where you have multiple loads and multiple generators to monitor.

Build a 12-input pulse counter - multiple input pulse counting

Arduino sleep mode

2010-12-11T06:58:00.000-08:00

An interesting tutorial on putting the arduino to sleep to save battery. I'd like to try this to create a simple mains AC sensing unit that runs of battery and transmits power values to a receiver.. to come..

http://interface.khm.de/index.php/lab/experiments/sleep_watchdog_battery/

PCB Experiments

2010-12-09T16:00:00.000-08:00

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: http://openenergymonitor.org/emon/node/109

Using JQuery AJAX and php to fetch data from a mysql database

2010-12-08T08:52:00.000-08:00

A brief tutorial on using JQuery AJAX and php to fetch data from a mysql database

High resolution ADC and Arduino

2010-12-03T08:11:00.000-08:00

Worth a look at:

http://arduino.cc/blog/2010/11/29/tired-of-a-10-bit-res-hook-up-a-better-analog-to-digital-converter/

Energy monitoring at the CAT - part 4

2010-10-10T11:11:00.000-07:00

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

2010-10-10T10:54:00.000-07:00

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: http://openenergymonitor.org/emon/node/89

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: http://openenergymonitor.org/emon/node/88

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 http://openenergymonitor.org/emon/node/79

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...

Energy monitoring at the Center for Alternative Technology - part 2

2010-10-10T10:44:00.000-07:00

continuing from part 1:

The micro grid display

Enter Carlos!

Carlos has been developing the public energy display for the microgrid, so that visitors at CAT can see exactly how much energy all the renewable generators are producing and how much CAT is using. The display has a load of good features: graphs, statistics, comparison bars and other relevant info. Here's a screen of the total generation page of his display:

The display is programmed in php, and the interface between the database and the display is done via a script that creates an xml file and jpg graphs from data in the database and then a second script that fetches the jpgs and xml file and displays the output.

Carlos is very much an open source fan an we have been having some great discussions about were this open source energy monitoring and energy visualisation displays could go, we have some exiting plans in the works that I will come back to soon...

First a bit more about the current system in part 3...

Energy monitoring at the Center for Alternative Technology - part 1

2010-10-09T16:27:00.000-07:00

Over the last two months I have been doing a project at the Center for Alternative Technology (CAT). I have been working on the monitoring system for the microgrid they have there, its has been and continues to be a really fascinating and enjoyable project.

CAT is one of Europe's leading sustainability center's, it is a university, a visitors center a pulisher of books, reports such as zerocarbonbritain and a place were practical solutions, sustainable technologies are tried out, tested and demonstrated.

For a sustainable technology enthusiast like myself it is a great place to be. There is a lot of green technology there! A very large PV roof, several hydro turbines, wind turbines, woodchip and pellet boilers, CHP plant, heat pumps and many others I'm sure I have missed. The electrical generation technologies are all connected up to a microgrid and there is a heat main on the heating side of things.

The microgrid is really interesting, Jaise Kuriakose is the electrical engineer for the microgrid and has designed the system. I recommend having a read of the follwoing articles, blog posts and Jaise's presentation about the microgrid:

Turned on! The UK's first Island Micro Grid Goes Online article.

Turned on! The UK's first Island Micro Grid Goes Online blog.

Distributed, Smart and Micro grid systems presentation.

Monitoring

On the monitoring side there are pulse output kwh meters on all the renewable generators and non interruptible mains loads. As the microgrid is a recent addition, when I started these meters were not connected up to a data acquisition/logging system.

I spent the first couple of weeks connecting up these pulse output meters to the scada system that was in place for the previous monitoring setup and then configuring the scada system for the new metering setup.

The immediate aim of this was to get data to the microgrid public energy display, which I will write about next in part 2.....

Networked Arduino's and PV monitoring weekend

2010-08-29T09:03:00.000-07:00

Last weekend a group of us gathered in the mountains of north wales (were I live) for a build session: Ken Boak and Suneil Tagore made the long trek from London and Cardiff and Glyn Hudson came from just down the road.

We spent the weekend developing a networking system for Arduino's applying it to monitoring a PV system. Ken Boak has written two good blog posts detailing our work on his blog, have a look:

Wired network for arduinos

Snowdonia weekend hack session

The team from left to right: Suneil Tagore, Trystan Lea, Ken Boak and Glyn Hudson

Appliance Inference

2010-08-02T13:38:00.000-07:00

A start on an investigation into the possibility of inferring what appliances are on and how much energy they use (especially their kwh per day usage) from one measurement point at the supply to the house/building. If this can be done effectively it would be a much cheaper and less intrusive way to find out such information than placing a separate meter on each appliance. http://openenergymonitor.org/emon/node/86

Nuelectronics ethernet shield simple client library

2010-07-31T12:04:00.000-07:00

Just put together a simple client library for the nuelectronics ethernet shield and a couple of examples including sending data to pachube, it can all be found here:

http://openenergymonitor.org/emon/node/80

Reading from pulse output kWh meters

2010-07-30T04:15:00.000-07:00

A new guide on reading power and energy from pulse output kWh meters:

http://openenergymonitor.org/emon/node/79

Alan Meany's Ambient Knowledge

2010-07-23T04:43:00.000-07:00

Check out Alan Meany's Ambient Knowledge energy monitor project using the non-invasive Mains AC method, its a really nice idea, from Alan's website:

"Ambient Knowledge is a lamp that glows different colours to display the current consumption in your home. Ambient Knowledge is an Ambient Energy Information Display that provides you with energy information in a visually pleasing, easily accessible convenient, glancable manner. At a quick glance AmbientKnowledge will make you aware of how much energy your house is consuming in a subtle simple approach, with minimal effort needed."

Alan will be exhibiting Ambient Knowledge at Ars Electronica 2010 in Linz, Austria 2nd - 11th of September.

Project Update

2010-06-30T12:48:00.000-07:00

This is a joint blog post from Suneil Tagore and Trystan Lea. Last week we met up in North Wales and spent a good part of the week looking at the next step for the openenergymonitor project. We thought about: How it could be organised and described better. How it could be made more useful for other participants/users/developers, and how it could better reflect our ideas for the project and also our activities using the technology.

One of the main aspects that we would like to expand on is the idea of modularity.

Lets say you build a solar hot water controller, the solar hot water controller has the Arduino microcontroller platform at its heart, 1 of the 6 analog inputs and 2 of the 14 digital channels is used for the 3 multiplexed RTD temperature sensors. 1 other digital channel is used for the pump control. That leaves 5 analog channels spare and 11 digital channels. The cost so far has been £20 for the Arduino and between £5-8 for the temperature sensor electronics and pump control. For another £12: the price of a couple of resistors, capacitors a CT sensor and AC-AC adapter: mains AC energy monitoring can be added using only 2 more analog inputs. The mains AC energy monitor and the solar hot water controller share the same arduino and can also share for example an LCD and ethernet connection. This ability to share resources enabled by such a modular system can ultimately yield significant overall benefits in terms of energy efficiency, material efficiency, cost reduction, convenience and usability compared with having a separate device for each energy monitoring and control application.

To make this possible one of the main tasks will be deciding on documentation standards so that each bit of documentation can fit together with the other bits, this will need a bit of thought and work.

Another important element of making modularisation easy to work with will be developing Arduino libraries for the modules so that the software side is straightforward to program and also possibly investigating standardized connections between modules.

To start with we thought it might be best to divide the modules into types:

Input modules

Modules for measuring things, for example: Electricity, Heat, light, wind, fluid flow, etc

Actuator modules

Modules for controlling things, for example electric pumps or dump loads.

Data Modules

Displays, Computer and Internet based graphing

Each module would have a description of what it is and how it works, a list of parts - including possible suppliers, circuit design (if applicable), and a section on how to connect it to an Arduino including details on software and calibration (if applicable).

The next part to the documentation is the builds section: how to bring more than one module together to do something more useful and interesting like a solar hot water controller or a solar hot water controller / energy monitor combo.

After that is case studies. Which brings us on to another important topic. As well as developing this technology we hope to use it in our own homes and also look into how we can use it as a part of a service that we could offer, at the moment one idea in its early stages is to explore offering an energy auditing ,renewable energy feasibility and renewable energy installation service in our local areas. Suneil is just in the middle of his first solar PV installation and is developing a solar monitoring unit for the installation. Both of us taught a wind turbine making course at Atlantic college in south wales this year, and as a part of that we will be installing wind turbine monitoring. The case studies section will document the use of the openenergymonitor project in projects like these. One of the aspects of this is that as we experiment with making a living we hope to help other do the same.

Last but very much not least: the updated website has a section on local manufacturing. One of the main things we would like to explore as a part of this project is the idea of local manufacturing: Being able to make the things we want and need either in our own homes or in labs/workshops and small businesses in our local communities. This is a really exciting idea and emerging possibility that was a large part of the inspiration to do this project.

To learn more about local manufacturing also often called decentralised manufacturing or desktop fabrication have a look at the following projects that are pionnering the idea: RepRap the project to build an open source 3D printer and MIT FabLab’s; 100kgarages; a book by Kevin Karson and more resources on p2pfoundation manufacturing page.

So over the next few weeks there shall be changes a foot on the website as we attempt to organise it along the lines of what we have described above and the project starts to move more along this direction.

We would like to thank Ken Boak who has helped us refine the ideas above, especially those on modularity. Ken Boak is very knowledgeable energy monitoring and sustainable technologies enthusiast, and documents many of his findings on his blog sustainable suburbia.

Please feel free to join in and share your thoughts and ideas on this project. The scope for developing new applications and real world case studies/installations is limitless; posting your findings here is most welcome in this collaborative project. Hope to hear from you soon!

Solar hot water controller

2010-06-14T05:14:00.000-07:00

Well its been a while since I last updated, I managed to get some time over the last month to build a solar hot water controller for the navitron evacuated tube system we have installed here on our house, its been a project I wanted to do for a while. I've documented version 1.0 of the design here:

Solar hot water controller v2.0

Apart from the usefulness of being able to log data from the solar hot water controller I'm interested in looking at combining data from the solar hot water controller with data from the energy monitor. It would be interesting to see if its possible to calculate accurately how much immersion heating is displaced by the solar hot water system as well as how well the system is working compared with its expected output.

Here is a graph of the different system temperatures plotted with flot

All Power Labs

2010-04-29T08:59:00.000-07:00

A couple of weeks ago I visited All Power Labs over in Berkeley CA on the recommendation of Ken Boak who went over there for a workshop in March. All power labs are:

“..an incubator for open source energy experiments and distributed manufacturing solutions. We work to generate physical tools and information resources for people exploring alterative energy through DIY innovation and online collaboration. We believe that a bottom up, participatory ecology in energy is just as possible as it has been in computing. And we expect the impact of such creative self-determination will be no less transforming than its been in digital realms.”

Their current main project is called the GEK gasifier, (Gasifiers Experimenters Kit). The GEK gasifier converts biomass (woodchip etc) into wood gas, this gas can then be run in a car or burned for heating or used to generate electricity by running a gas turbine (they have a gas turbine!)+ generator or internal combustion engine + generator. The gasifier+engine+generator combination is called the Power pallet and can produce 10kW.

Bear Kaufmann who is investigating the performance of the system was looking for energy monitoring equipment and so Mario and I went over to see the operation and work with Bear on getting some energy monitoring working.

The generator they are using is a single phase 3-wire generator that is effectively the same configuration as household electrical wiring in the states. The energy monitoring setup therefore consisted of 2 CT sensors for current measurement: one for each leg a step down transformer for voltage measurement.

The power pallet has a gasifier control unit (GCU) which is based on the Atmel ATmega 1280 which is used in the Arduino Mega and so the unit is compatible with and uses the Arduino IDE for programming. The GCU has a lot of things happening on it: it monitors temperatures and pressures and controls things like flow to keep the gasifier working efficiently, there are critical servo updates that happen about every 20ms and so the main challenge of the visit was to try to fit the energy monitoring on to the GCU, to fit the real power, apparent power, powerfactor, vrms, irms sampling and calculation into those 20ms time slots. Up until now I have usually had the arduino dedicate around a second to make these measurements and so the question was could we squash the energy monitoring down and still get accurate results. Luckily we found we could do this, by taking one wavelength long samples and then averaging around 10 of these one wavelength samples to get a more stable result and so now the power output and efficiency of the power pallet can be tested with out a lot of extra equipment just a couple of sensors, resistors and capacitors connected to the GCU.

Here's a test output with different loads:

For more information have a look at Bear's post and write up here: http://gekgasifier.com/forums/showthread.php?p=1295#post1295

I will also try to upload the code for single phase 3-wire and the one wavelength sampling soon as I get a chance.

ArduinoComm code simplified

2010-04-11T11:52:00.000-07:00

No need to have those A B C D E .. identifiers any more. More info and new version: http://openenergymonitor.org/emon/arduinocomm

Mains AC: non-invasive version 3.0 up

2010-04-07T16:02:00.000-07:00

The documentation for version 3 of the Mains AC: non-invasive energy monitor is up. It can be found here:

Mains AC: non-invasive version 3.0

The main changes are:

Electronics

2x 10uF bias stabilizing capacitors added significantly improving accuracy: more info
Changed Voltage measurement circuit
Power for arduino comes from a seperate transformer to AC voltage measurement transformer.

Software

Arduino sketch rewrite, sketch now follows Atmel's AVR 465 app note method, adding:
- Phase calibration
- Digital high pass filter to remove offset.

Other

Much simplified calibration

There is also new more detailed documentation with this version, including separate pages on:

How to build it

Accuracy

Detailed system design

AC Power Theory 1

AC Power Theory 2

Household wiring

Further development questions

I've also done a bit of re-arranging of the documentation layout, trying to make the website a little easier to navigate, if you have any suggestions on this they would be very welcome.

Mission Science Workshop Project

2010-04-06T17:36:00.000-07:00

I'm currently in San Francisco :) I'm here helping an organisation called Mission Science Workshop, who are interested in developing a course based on the energy monitor for high schools. The idea is to use the arduino and computer based graphing/logging as a platform to make scientific measurements of things like: voltage, current, power, energy, temperature, light, etc, that can be used in workshops to make it possible to see useful, interesting phenomenon and demonstrate the use of computers in science. Mission Science Workshop teach science in a very hands on, experiential way, trying to keep kids curiosity alive and sparking their interest in science. Have a look at their website here:

http://www.missionscienceworkshop.org/

I'm working with Mario Landau Holdsworth from mission science on the project, he teaches at Mission Science and has a keen interest in Arduino's, energy monitoring, electric cars, mycelia and teaching science in a fun way. He has been very kind to sort out the whole visit.

As a part of the mission science project I gave a short workshop on the energy monitor last Friday. For the workshop I did a bit more work on the energy monitor design and tried to improve the documentation a bit, creating a printable energy monitor guide. I'm going to upload these to the main website today, but here are the printable pdf's for the mean time:

I'm in the San Francisco area until the end of the month, working on the project and going hiking around marin county and hopefully Yosemite, if your in the area, Mario and I will be down at Mission Science building things so let us know if you'd like to come and have a look.

Maker Faire, How to build an energy monitor guide

2010-03-18T04:10:00.000-07:00

I put together a printable how to build an energy monitor guide for the maker faire last weekend. Its a current measurement only energy monitor with breadboard assembly instructions and instructions on how to add a nokia 3310 LCD screen. To read about it have a look here:

How to make a simple energy monitor

The nokia 3310 LCD screen from nuelectronics is really nice.

Reducing noise, adding a capacitor

2010-03-18T03:20:00.000-07:00

I recently bought a new laptop and when I plugged it in to the mains and connected up the energy monitor via usb and monitored the current of one light the current value it read was much higher than what my reference meter said it should be. I got the following results:

Load description: One light
Energy monitor power supply: Laptop mains connected.
Energy monitor: 1050mA reference meter: 189mA

Load description: One light
Energy monitor power supply: Laptop running off battery.
Energy monitor: 186mA reference meter: 189mA

I loaded up the waveform sampler program to see what was going wrong and saw this when the laptop was connected to the mains:

When the laptop was not connected to the mains the fluctuations largely disappeared.

I then checked to see what the energy monitor would read when powered by an external supply rather than the laptop supply. The energy monitor was now a lot closer to the reference meter than before:

Load description: One light
Energy monitor power supply: External power supply
Energy monitor: 225mA reference meter: 191mA
The laptop is not connected to the mains here.

Load description: One light
Energy monitor power supply: External power supply
Energy monitor: 215mA reference meter: 191mA
The laptop is connected to the mains here but on a separate plug socket.

Interestingly the laptop still produces an effect even when its plugged into another socket not part of the measuring setup. The other thing to note is that the energy monitor current is higher by about 20-35mA with the external power supply than when powered by the laptop running off its battery.

It would clearly be nice to get rid of the noise when the laptop is connected to the mains and the difference in measured current between the different power supplies.

Reading through the Atmel AVR465 application note, they use a 10uF capacitor across the biasing voltage divider to stabilise the DC level. I added the capacitor and low and behold the noise and difference in power supplies disappeared and now the results are much better :) The energy monitor now reads

Load description: One light

Energy monitor power supply: Laptop mains connected.
Energy monitor: 194mA Reference meter: 191mA

Energy monitor power supply: Laptop running off battery.
Energy monitor: 194mA Reference meter: 191mA

Energy monitor power supply: External power supply.
Energy monitor: 193mA Reference meter: 191mA
The laptop is not connected to the mains here.

Energy monitor power supply: External power supply.
Energy monitor: 193mA Reference meter: 191mA
The laptop is connected to the mains here but on a separate plug socket.

The variation between power supplies and the effect of the noisy laptop power supply is significantly reduced.

Here's a screenshot measuring the same lamp as I was measuring above with the energy monitor powered from the laptop connected to the mains but now with the 10uF capacitor across the 2.5V bias:

Very steppy but this is due to the small magnitude of the signal versus the ADC resolution which is expected, the large noise fluctuations have disappeared.

Here's the new circuit diagram:

Component values

CT sensor turns ratio – for the efergy sensor seems to be 1:1500 which means the current in the secondary windings will be 1500 times less than the current in the mains primary winding.

RsensI - Dictates the range that the current can be read over.

56Ohms gives a current range of 0 to 47Amps (with efergy CT, turns ratio: 1500)
100Ohms gives a current range of 0 to 26Amps (with efergy CT, turns ratio: 1500)

C1 – The bias stabilizing capacitor.

Noise decreases as the capacitor size increases.
Energy monitor start-up time increases as capacitor size increases – this is the time taken for the capacitor to charge, measured as the time it takes for the current measurement to reach within 20mA of the final value. Only a noticeable delay the first time you put the energy monitor on.
Atmel recommends a 10uF capacitor in their AVR465 app note.
10uF works well, I tried a couple of other values and there doesn't seem to be a very noticeable difference at 4.7uF, 1uF, 0.1uF, needs further testing to establish exactly how much difference there is between the values.

Rvd – 2x equal sized voltage divider resistors

Increasing the resistor size decreases current consumption in the voltage divider.
Increasing the resistor size increases noise due to high impedance.
Increasing the resistor size increases the energy monitor start-up time due to charging of C1.
2x 100k resistors and a C1 of 10uF gives a start-up time of 16s.
2x 10k resistors and a C1 of 10uF gives a start-up time of 4s.

I've also removed the 100Ohm current limiting resistor from the above circuit as I'm not sure that it was really doing anything, I put it in there out of general practice, feel free to use one if you like.

Its also worth adding a 10uF capacitor on to the voltage measurement circuit in the same place. I will discuss that in more detail soon along with some other changes to the voltage measurement electronics.

Application Notes

2010-03-11T06:46:00.000-08:00

Been realising what a great source of information application notes are, when I started this project I didn't really know were to look to get good information on energy monitoring but I think I'm slowly getting better at it now :) I've put together a page here:

http://openenergymonitor.org/emon/node/51

which is full of links to application notes. Thanks to Danny for the link to the AVR-465 note on creating an energy monitor with an atmel micro. Its even got open source firmware details there and an interesting use of opamps to increase accuracy at low current ranges which I'd like to try at some point.

If you know of any other good resources, Id be interested in knowing about them, please post them below, thanks!

Maker Faire Newcastle

2010-03-10T14:40:00.000-08:00

I will be at Maker Faire 2010 in Newcastle this coming weekend (March the 13th-14th) and will be exhibiting the energy monitor, should be a fun event! drop by if your in the area.

ArduinoPower - ADE7753

2010-02-15T01:40:00.000-08:00

Last year I met James Devine at homecamp a home hacking, automation and green technology unconference in London. He has been developing an arduino energy monitor based on an Analogue Devices ADE 7753 IC which is a custom energy meter IC for use with CT sensors. The ADE7753 looks like a really good way of doing the measurement, it communicates with the arduino via SPI and does all the energy metering calculations itself, therefore freeing up the arduino for other tasks.

Here's a mockup picture from his site of the energy metering arduino shield that he is developing:

His project aim is to create an accurate desktop scale power meter, suitable for measuring individual power usage at a desk, the power meter then communicates with a PC I think via the arduino bluetooth shield and it's all open source, have a look: http://arduinopower.pbworks.com/

Forums!!

2010-02-03T02:46:00.000-08:00

I've just set up a forum here:

http://forums.openenergymonitor.org/

It might be easier to use than the comment pages on the website and a bit easier to see what's going on.

Calibration

2010-02-02T06:39:00.000-08:00

I've updated the calibration information for the voltage and current measurement board and also done some accuracy and precision testing. Both can be found here:

http://openenergymonitor.org/emon/node/42

Documentation finished

2010-01-28T11:17:00.000-08:00

The documentation for the whole home energy monitor is finished and can be found here:

How to build a whole home energy monitor

The main addition's are:

Full Arduino sketches uploaded
Hardware wiring diagram
Full part list and cost breakdown

Arduino Ethernet Shield + perl + mysql + Flot based graphing

2010-01-27T13:24:00.000-08:00

Finished another section:

How to look at your energy consumption on the web

Xbee documentation

2010-01-26T02:17:00.000-08:00

Just finished the Xbee documentation it can be found here:

How to add an Xbee wireless link

Display documentation

2010-01-23T15:31:00.000-08:00

The Display documentation is finished and can be found here:

How to add a Display

USB pen data logger documentation

2010-01-22T13:42:00.000-08:00

The USB pen drive data logger documentation is finished and can be found here:

How to add USB pen data logging

Main documentation page started

2010-01-21T11:26:00.000-08:00

Made a start on the main documentation page for the whole house energy monitor. It can be found here:

How to build a whole home energy monitor

Measurement board documentation

2010-01-21T08:08:00.000-08:00

Just finished the measurement board documentation it can be found here:
http://openenergymonitor.org/emon/node/42

The measurement board contains the voltage and current measurement electronics and the power electronics for providing power to the arduino in the main unit.

Finished, working, functional home energy monitor!

2010-01-13T13:47:00.000-08:00

I have spent some time over the last couple of weeks working on getting a finished energy monitor for the house together and installed in a more permanent way. I managed to finished the build yesterday and it's now working away logging energy consumption data, giving some informative readouts and nice looking graphs :)

I decided on having a real time display that can be mounted in some ware visible with a cable running to the main unit that holds the sensor electronics situated near were the mains comes in to the house. The main unit also has a USB pen data logger in it to store detailed data. I also wanted to send data to be graphed on the net and so I have another box near my router that has a second arduino and an arduino ethernet shield in it. The ethernet box is connected to the main unit with a wireless xbee connection.

Its quite a complex setup and a bit pricey but I wanted to learn about each element and since I had bought a couple of arduinos, xbee's etc I thought I'd through it all together and make something with lots of crazy and useful things going on in it...

Here are some pics of the setup:

The display unit consisting of 4 large green led 7 segments. On the right is a 6 mode – mode chooser so that you can select by turning the potentiometer (bottom – right) whether the display shows real power, apparent power, power factor, RMS Voltage, RMS Current, frequency or cumulative kWh used. The display is connected to the main unit by a cable that goes through the wall at the back of the display.

The main unit is the small box in the far left of pic with the white CT sensor wire crossing the shelf over to the sensor clipped on to the main mains wire on the right.

The ethernet unit connected to the router, the small box on top of the larger box houses the xbee and can be detached if one wanted a wire connection instead.

A screenshot of the web based graphing that can be seen live here.
Graphing is done using flot – a very nice piece of software.
I'd like to thank John from jarv.org for his work and help on logging using the ethernet board although he is using open flash charts much of the implementation is very similar.

For more pictures of the setup check out the picassa album here.

Over the next two weeks I hope to document it the setup. I hope to manage a section every couple of days in the order of the features below:

Main Features

Voltage measurement with step down AC to AC adapter,
Current measurement with CT sensor.
Power for sensor board provided with same AC to AC adapter used for voltage measurement.
Calculation of Real power, Apparent power, power factor, RMS voltage, RMS current, frequency, cumulative kWh.

Display unit consisting of large green 7 segment display, 6 mode – mode chooser and red/green led indicator to indicate when grid is below and above 50Hz.

USB pen data logging using VDIP1 board

Xbee wireless link from sensor unit to the Ethernet unit.

Ethernet board for logging and graphing on internet.

Flot based graphing on website.

Block diagram of the setup:

Micro Maker Fair Wales

2009-10-22T16:34:00.000-07:00

Myself and Suneil will be exhibiting the energy monitor and wind turbine at Micro Maker Fair Wales in Chapter arts center in Cardiff tomorrow and Saturday 11am - 4pm. The Maker Fair is a part of the may you live in interesting times festival, read more about it here:
http://www.mayyouliveininterestingtimes.org.uk/makersfaire.html

Come along if your in the area!

7 segment display and more internet stuff

2009-10-09T14:44:00.000-07:00

Finally got the 7 segment display I've been meaning to build for a while built, its great being able to see power usage without having to have the computer on and the big green digits are really nice and clear.

Here's a video of it in action with a bit on pachube and appspot at the end:

CT sensor with Display and Internet from Trystan Lea on Vimeo.

I using a MAX7221CNG driver chip with four 1" green digits, following the tutorial (a very good tutorial I may add!) on the arduino site by wayoda here:

http://www.arduino.cc/playground/Main/MAX72XXHardware?action=diff

Here's the arduino sketch I used in the above video:

http://openenergymonitor.org/emon/sites/default/files/CTDisplaySerial.pde

and after playing about with ladyada's python code from tweet-a-watt Im now using python on the computer side.

Here's the python script that outputs values to terminal, a file, pachube and google appspot:

http://openenergymonitor.org/emon/sites/default/files/main9oct.tar.gz

Feels like things are coming together :)

Ive got an asus rooter on order and an arduino ethernet board to play about with so hopefully will not need the computer to be on all the time for data logging soon. Id also like to have a look at enclosures for the display to make things look nice.

Pachube

2009-10-05T14:23:00.000-07:00

Got a pachube feed going. See the gadget on the side ->

To check out my pachube feed page in more detail:

http://www.pachube.com/feeds/2801

From pachube's website:

"Pachube is a web service available at http://www.pachube.com that enables you to store, share & discover realtime sensor, energy and environment data from objects, devices & buildings around the world. Pachube is a convenient, secure & scalable platform that helps you connect to & build the 'internet of things'."

Internet connectivity and xbee wireless - what a day!

2009-10-04T13:59:00.000-07:00

Decided to have a go at getting my xbee's to work this morning so that data can be sent wirelessly from the sensors to the computer.

Followed ladyada's tutorial here:

http://www.ladyada.net/make/xbee/point2point.html

and it works!

I then thought id have a go at following her tweet-a-watt internet connectivity tutorial using google appspot and visualizations here:

http://www.ladyada.net/make/tweetawatt/database.html
http://www.ladyada.net/make/tweetawatt/graph.html

also works! great tutorials!

Here's a couple of minutes of realpower measurements graphed with google visualizations:

http://openenergymonitor.appspot.com/graph

and the last 10 power values:

http://openenergymonitor.appspot.com/

I had to modify a couple of things to get it all to work with the Mains AC: non-invasive method, I will post up a how to and source code soon as I can.

Next id like to try to use the Asus wifi router to remove the computer altogether that ladyada details here:

http://www.ladyada.net/make/tweetawatt/expand.html

and Ive got components for a 7 segment display on order.

Hall effect sensor circuit diagram

2009-09-03T16:23:00.000-07:00

The circuit is an inverting amplifier circuit. The 100k pot level shifts the input signal. It can be set so that the output lies within the arduino's 0 to 5V input range. The 1k pot sets the amplification factor. By varying both pot's it is possible to set the current measurement range of the circuit. Note the output is inverted so that when the current increases the signal input to the arduino decreases from 5V to 0V.

Experiments with a hall effect current sensor

2009-09-02T14:58:00.000-07:00

Thought Id have a go at using a hall effect sensor to measure current. A hall effect sensor can measure DC and AC current, Ive had a go at the DC and it seems to work quite nicely, its also quite a bit cheaper than the other DC current measuring method I detail here, which is always good!

Here's a pic of the setup:

I bought the hall sensor from farnell here.

It requires a supply voltage of between 6 and 12. Its output is centred around Vcc/2. The output voltage increases about 50mV per Amp when the supply voltage is 12V. When measuring DC current the output looks like this:
0.0A - 6.0V
1.0A - 6.05V
2.0A - 6.10V
...

I've used an inverting amplifier to invert the signal about a set voltage so that the voltage going to the Arduino's analog in is between 0 and 5V. I will upload the circuit diagram and further details soon when I get a chance.

So far it looks like a promising method.

OpenCO2Monitor collaboration

2009-08-25T01:51:00.000-07:00

A couple of days ago I was contacted by Ronic Concepcion and Ymreb Momville from the University Southeastern Philippines who are undertaking a technical research project called OpenCO2Monitor as a part of their BS Information Technology degrees.

Their project will be a collaboration with this project using the Mains AC:Non-invasive method of energy monitoring to supply energy consumption information to their software.

From their blog: http://openco2monitor.exofire.net

"OpenCO2Monitor is an open source software which is capable of monitoring CO2 emissions on a house/building. When the emitted CO2 reaches danger levels, the software will automatically sound an alarm and show a message dialog on the computer screen tell the user what to do.

OpenCO2Monitor is not only capable of monitoring CO2 levels but also monitoring the electric energy consumption of a house/building. It is also capable of showing your current monthly bill based on the Davao Light and Power Company generation charge per kilowatt hour.

OpenCO2Monitor also shows how many number of full grown trees a house/building should have in its surroundings to offset its CO2 Emissions. It also displays the house/building’s current contribution to temperature rise.

OpenCO2Monitor uses the Mains AC:Non-invasive method from OpenEnergyMonitor.org to read the Kwh Usage of a house/building."

All really useful information that aims to help the user to "save money and energy while lessening their contribution to greenhouse gasses."

36 hours of house electrical energy use monitoring

2009-08-19T11:23:00.000-07:00

Here are some KST graphical outputs of whole house electrical energy use over about 36 hours using the non-invasive method.

The large peaks is water heating. The small ones may be the fridge switching on and off.

zoomed in a bit.. a few hours:

Im quite happy with this method now, its nice, simple and safe.

Measuring DC electrical energy production from micro-renewables

2009-08-14T15:45:00.001-07:00

Just finished writing up a page about measuring DC electrical energy production from micro-renewables. I built is for measuring the output of the wind turbine. Seems to work quite well although I need to do a bit more work on calibration.

Here's a video of it all working, sorry about the rushed and blurry video taking...

Monitoring the output of the wind turbine. from Trystan Lea on Vimeo.

Measuring AC mains energy use the non-invasive current transformer method - part 2

2009-08-05T06:18:00.000-07:00

Over the last few weeks I have been working on measuring AC mains energy use using the non-invasive current transformer method. I've updated the website with a page about what I've done and how it works here (there's still some work to be done on the page, but most of the info is there now).

Measuring energy use in a power strip above- but is just as easy to measure whole house electrical energy use by cliping the sensor to the mains input to the house.

Printable one page project description

2009-08-04T08:50:00.000-07:00

I've put together a printable one page project description. Useful for when I need to describe to people what Im working on. It can be downloaded in pdf form below.

OpenEnergyMonitorProject.pdf