OpenEnergyMonitor Shop is open!

It's taken a bit longer than we expected but finally we can proudly announce that our on-line shop is open for business!

Last week we 'soft launched' the shop to friends, members of the community and our twitter followers. We would like to say a big thank you to everyone who's supported the project by making a purchase through the shop. We have been a little overwhelmed by the level of interest. Again, thank you, you guys are amazing!

In the shop we sell all the components needed to build an Arduino based wireless, web-connected open-source energy monitoring system.

Component kits for the main OpenEnergyMonitor modules are available in the shop:

emonTx - wireless energy monitoring transmitter unit

emonGLCD - wireless graphical LCD display unit with on-board LED's & sensors

emonBase - NanodeRF wireless, web-connected base station
We also sell CT clip on current sensors, optical utility meter pulse detector sensors, temperature sensor and power supplies.

This system is still in development, it's not an end user consumer product. It is however functional and very flexible in it's current form. Being Arduino based and using standard Arduino software libraries, it's easy to customise the system to meet your needs.

One motivation behind opening the shop is that by selling the units in development kit form it removes barriers to entry and empowers members of the OpenEnergyMonitor community to to get involved with the project. Revenue raised through the shop will go directly towards funding more development and sustaining ourselves so we can continue working on the project.

In the near future we are planning to move to surface mount electronics to enable pre-assembled units. See our newly updated vision page for more information on how we see the project progressing in the future.

emonGLCD V1.3 PCB

Introducing the latest version of the emonGLCD PCB.

This latest version (V1.3) fixes a few minor issues with the previous version (V1.2) but also has some issues of its own. It's a case of two steps forward and one step back.

The good news:

  • The LDR light sensor no longer suffers from reduced sensitivity due to sharing a port with one of the LCD pins 
  • Both tri-colour LEDs are on ATmega328's hardware PWM ports allowing the brightness to be controlled with some nice dimming effects 
  • New new rear silkscreen design featuring a handy RFM12B frequency note area and a large Welsh dragon graphic! 
The bad news:

  • The new feature in V1.3 was suppose to be two extra push switches to allow for future screen navigation. Unfortunately due to a PCB layout error non of the switches on V1.3 are functional. While this is frustrating since it was an easily avoidable mistake the display is still very functional. The current firmware example for single CT energy monitoring and solar PV monitoring don't really make much use of the switch. 
The good news!

Everything else LCD, wireless, ATmega 328, Light sensor, Temperature sensor and multi-colour LED's work great. We have decided to go with the switches not working for now as it still makes a very functional energy monitor display. 

emonGLCD V1.3 front
emonGLCD V1.3 rear 
V1.3 assembled
The schematic and board design for emonGLCD V1.3 are up on solderpad:

The emonGLCD documentation page has been updated with the new port mappings:

Documentation reorganisation proposal

The current front page

It has been pointed out several times that the documentation on this site is hard to follow. We've been giving this some thought and have come up with a plan for hopefully what will be a clearer structure.

Here are our initial thoughts:

1) We start with the following headings, these form the main menu:

Community | Applications | Modules | Fundamentals | Tools | Archive

These headings contain:

  • Forums
  • Development plans
  • Links to community builds and blogs
Applications are step by step guides of how to assemble modules to create a particular system. They start with a short description then a step-by-step type structure. Detailed application discussion would be on a second page or blog post with link through.
  • Power monitoring
  • Solar PV
  • Solar hot water
  • Pulse counting
  • Heatpump monitoring
Applications reference through to modules below.

Separate github folder for each application containing sketches for all the modules that make up the application.

  • Hardware
    • emontx
    • emonglcd
    • emonbase
    • See-a-watt
  • Software
    • emoncms
    • Pachube
Each module contains the pages:
  • page1: overview + features (maybe use it: application list is referenced here?)
  • page2: built it / install it / buy it
  • page3: detailed design documentation
All emon system sections reference through to fundamentals section below


Getting started with arduino, uploading sketches etc.

Electricity monitoring
  • AC Theory - Introduction
  • AC Theory - Advanced
  • AC Theory - 3 phase
  • Power in different countries
  • Non-invasive
    • CT sensors - Introduction
    • CT sensors - Advanced
    • Current only - Single Phase
    • Current and voltage - Single Phase
    • 3-phase Monitoring
  • Invasive
    • AC shunt
    • DC Shunt & hall effect sensing
  • Appliance inference - labs
  • Interfacing with inverters
Pulse counting
  • Single pulse counting
  • 12 input pulse counting
  • DS18B20 temperature sensing
  • PT1000 temperature sensing
  • RF
  • RFM12B
  • xbee, zigbee, old rf
  • Master/slave simple serial networking
  • Ethernet
  • GLCD
  • 7segment, 3310
  • USB Pen drive data-logging
  • SD Card logging
  • Relay
  • Watchdog timer
  • Structures for transmitting data.
  • Sleep mode
  • String constructor
Github sketches for the fundamentals section could be contained in one github folder called fundamentals.

Tools that can be useful in debugging / development of systems:
  • VI Sampler
  • KST based graphing and statistics
  • Programming nanode with arduino
Items for archive

Other changes
We've disabled comments on pages, the thinking here is that its getting quite hard to navigate the page comments as conversations at different dates and topics are all getting mixed together and that it would be better to have these discussions on the forum, where each forum thread has its own clear topic.

Every page can be put in a hierarchical order such as modules/hardware/emontx making navigation clearer.

A site map with all of the above.

Do you think this is a good idea? 
Any suggestions on how the website content can be better arranged would be greatly welcomed!

New emoncms features part 2 - Email notifier

Its good to know as soon as possible if there is an issue with an installed energy monitor, such as the base station dropping offline or a problem with RF connection. This is a rough and ready first implementation of an email notifier for emoncms, that sends you an email to say that a feed has become inactive or a feed is equal to a certain value. No longer are the days when you log in to emoncms just to find that there are two days of missing data as happened to me on feb 6-7 here

A walkthrough

1) Click on a feed in the feed list to bring up the feed view page, scroll down to the bottom and click on set notifications:

2) Select the events that you want notifications for. Notification on value and on inactive both work. Periodic notification is yet to be implemented.

3) Click on edit mail settings and enter in the recipient email address. This only has to be done once as it is the same for all notifications.

If you want to send the notifications to multiple addresses, just put in a comma between each address.

4) Unplug your emonbase!! and check your email:

Behind the scenes

Main scripts:


1) To use the notifier on your own server you will need php mail installed, to do this on ubuntu enter the following into terminal

sudo apt-get install php-pear
sudo pear install mail
sudo pear install Net_SMTP
sudo pear install Auth_SASL
sudo pear install mail_mime

2) In emoncms3/Includes copy the default.mail_settings.php file and rename too mail_settings.php and enter in your mail server settings.

3) Open the file cron.php and change the key password to something unique, this is used to ensure that only you can run the cron.php script.

4) Create a cronjob, in ubuntu start by opening crontab: $ crontab -e
Then add a cronjob that calls the cron.php script including the key that you created. To call the cron.php script once a minute try the following:

# m h  dom mon dow   command
* * * * * wget -q -O /dev/null "http://localhost/emoncms3/cron.php?key=YOURKEY

5) If your using the same database as a previous emoncms version, you will need to create the new notify database tables. This can be done in index.php by pasting require "Includes/setup.php"; in the top. Its probably worth removing it afterwards.

6) Configure your feeds as in the screens above!

New emoncms features part 1: blue message bar

Spent a bit of time implementing new features for emoncms today, the first one was a much needed but quite small addition: a themed location to output messages such as "user already exists" and so on, see the blue bar in the screen below:

Try it out here:

How it works

If you have a look at the user_controller here github user_controller.php
On line 28 and 29 you will see the following:

$output['content'] = "";
$output['message'] = "";
(ie line 65) $output['message'] = "Your new account has been created";

The returned output from the controllers used to be just the one variable $output now we have two, one for main body content output and the other for message bar output. These variables are passed through index.php to the theme The theme then places the message and content in separately themed locations.

Community Energy Plan maker

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.

Try it out:

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

Hello, my name is Baptiste GaultierWhen 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


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) :

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

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:


emonGLCD single CT:

emonGLCd solar PV:

Full web-connected home energy monitoring system

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. 

Solar PV Monitoring

I have just finished detailed documentation of an OpenEnergyMonitor Solar PV Monitor system see:

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. 

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

Please use the forums for discussion. 

Here's a bit of background to solar PV monitoring in the UK:

The Feed in Tariff scheme (FIT)currently running in the UK pays the home owner a fixed amount per kWh generated, the home owner also gets paid a much smaller amount per kWh exported. At the moment (Dec 2011) most homes in the UK don't have export or smart meters fitted, utility companies assume, for calculation purposes that the home owner exports half of the power they generate. The cost of importing power from the grid is higher than the amount paid per unit of exported electricity. Therefore it makes financial sense for the home owner to use as much of their generated power as is possible.

A monitoring system with a real-time living room display indicating the amount of power being imported/exported allows the home owner to attempt to match their power consumption to the power being generated. I.e. make tea when the sun is shining! Financial benefits aside it can be very interesting and satisfying to monitor the yield of your solar PV system.