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Open-source tools for energy monitoring and visualisation
Updated: 19 hours 53 min ago

Kettle vs Blanket

Mon, 08/12/2014 - 12:55
One of the things I love about monitoring energy is that it can be used to answer questions and inform decisions.

In my household we have recently purchased an electric blanket, I had always associated such items as an indulgent luxury! However at this time of year the temperature in our bedroom is often only just about in double figures (old property with poor heating and frugal use) necessitating a seemingly moderate luxury of a hot water bottle to warm the bed up a little.   
I assumed using the new electric blanket would result in an increase in our power consumption, however the energy monitor proved me wrong! 
Having the electric blanket on for 30min used about 0.1KWh while boiling 1L of hot water to fill at hot water bottle used about 0.16KWh of energy, 60% more! Also the electric blanket does a much better job of warming the bed then the hot water bottle, after 30min it was almost uncomfortably hot even with an ambient temperature in the room of 11 degrees! 

200W Electric Blanket on for about 30 min
Kettle heating 1L of water to boiling
Categories: Blog

Introducing RFM69CW

Mon, 08/12/2014 - 12:14
For sometime now the Hope RF RFM12B module has been our RF module of choice. This module was chosen for it's low cost, decent performance and importantly for us, an active development community. On the software side we use the excellent JeeLabs JeeLib RF12 Arduino library.

About a year ago Hope RF announced the RFM12B to be 'EOL' (End-of-Life), there has been a degree of confusion as to what exactly this means; currently manufacture of the module is still taking place and supply is still easily available. However, we acknowledged that the time had arrived to look for alternatives since Hope RF no longer offers support or recommends the RFM12B for new products. 
An obvious alternative that was explored by JeeLabs  is the Hope RF RFM69CW module, it uses SEMTEC designed silicon (as opposed to Silicon Labs in the RFM12B). It's pin-compatible with the RFM12B. Using the updated JeeLib driver the RFM69CW is be backwards compatible with RFM12B helping users of RFM12B to make a smooth transition. Thanks to JCW from JeeLabs and LowPower Labs for the work on developing the RFM69CW Arduino library. We have been working with JeeLabs to source modules and test the driver software.    
Hope RF RFM69CW

I will let JeeLabs/DigitalSmarties introduce the module 
"The recently announced RFM69CW radio module by HopeRF is a compact, powerful radio transceiver module for swapping data packets in the 868 MHz ISM band, using standard and enhanced FSK modulation. Great for sub-compact designs; just 4mm of mounted height from using an SMD precision crystal.
Though consuming a similar level of power, the RFM69CW receiver section can decode fainter signals than the classic RFM12B. The transmitter section *maximum* output power is +13dBm, considerably higher than the +5dBm of the RFM12B. The current drain at these (adjustable) higher power settings is correspondingly higher. With the better receiver sensitivity, many applications will not need to use the higher transmit power settings, potentially saving on battery life.

Comparing like-with-like, pairs of modules will generally have greater range and/or better penetration of walls/ceiling than when using pairs of the classic RFM12B.


The physical module is compatible with the PCB footprint on all current JeeNodes and JeeLinks. For details of the fast-evolving level of software support, see this Forum topic.

Control is via a fast SPI bus with reduced MPU loading. The recommended power supply range of 1.8 < Vdd < 3.6 V can squeeze almost the last energy out of depleting batteries without needing a boost converter."





Comparison tabled compiled by http://www.mikrocontroller.net/articles/RFM69


Early next year we will start transitioning to the RFM69CW, end-users should not notice a difference apart from a new input on the emoncms Inputs page 'RSSI' (Received Signal Strength Indicator), see below.

To simplify manufacture and module sourcing we will be standardising on 433Mhz, we will make available no-RF versions of units for users who wish to solder on their own 868Mhz modules. See forum thread

RFM69CW on the emonTx V3.4 
For early adopters we have limited numbers of RFM12Pi Raspberry Pi Expansion with RFM69CW module in the shop. Using the latest emonHub software (currently in 'Testing' branch) using the RFM12Pi with RFM69CW on a Raspberry Pi should be seamless, emonHub automatically detects the higher baud rate requirement of the RFM12Pi with RFM69CW (56700 as opposed to 9600 with RFM12B RFM12Pi) sets baud accordingly and starts posting RSSI (received signal strength indication) to emoncms.
RFM69CW on the RFM12Pi on Raspberry Pi Model B+
Example RSSI value from emonTH in emoncms
The RSSI readings are very useful as they give a quantitative means of comparing RF performance which should help when deciding on the positioning of units during install and developing better antenna setups.

RSSI readings from nodes setup in my house (mix of RFM12B and RFM69CW) 
RFM69CW on the upcoming emonPi Raspberry Pi Energy Monitoring Shield (due for launch in the new year) 
For more info on the RFM69CW see Building Block Overview Page:

http://openenergymonitor.org/emon/buildingblocks/rfm69cw

Categories: Blog

Research Project Call for Participants

Sat, 22/11/2014 - 14:20

In collaboration with Corina Sas from Lancaster University we would like to to evaluate members' experience of building, setting up and using our monitors and how these impact on people's understanding of energy consumption and household practices. The larger aim is to to explore how energy monitoring technologies could be better designed to support sustainable practices.

A team of researchers for Lancaster will run this study consisting of interviews lasting around 1 hrs. For this, a researcher will visit you in your home at your convenience, or if you live further away from Lancaster/Manchester, then Skype interviews can be arranged. As a thank you will be offer you an organic veg box.

The plan is to complete the study by end of the year. If you are interested and able to help, please contact the researcher with your available dates: Dr Corina Sas at corina@comp.lancs.ac.uk

Thanks a lot for your support.
Please post any questions to forum thread: http://openenergymonitor.org/emon/node/6156
Categories: Blog

Snowdonia household energy study, exploring zero carbon solutions

Fri, 21/11/2014 - 13:44
A couple of years ago Glyn and I and a friend of ours Bethan Gritten carried out an energy study with a local organisation called EcoBro of 17 households in Snowdonia, North Wales including our own.

We looked at the energy used by each household for electric, heating and transport and what the effect would be of applying the solutions outlined in both ZeroCarbonBritain and Sustainable energy without the hot air, visualising the result using David MacKay's energy stack graphics.

I've been looking again at this work recently as I find it a really useful and tangible way of looking at the energy problem and I've taken the opportunity to improve the energy stack graphic visualisation and put it up online here:

Dynamic visualisation:
http://egni.ecobro.org/data

The code for it is open source and on github here:
https://github.com/TrystanLea/energystacks

Here's a brief run through of what you can see:

Current Energy Use
This first graphic shows each households current energy use and where that energy is used:


24% of the energy used by the households come from renewable sources, whether biomass or 100% green electricity tariffs. The wide range of total energy use per household is quite interesting, using the dynamic tool you can explore the contribution of occupancy and floor area. You can also look at C02 and energy cost per household.

Solutions for reaching 100% sustainable energy for household electric, heating and transport.

In both the ZeroCarbonBritain report and David MacKay's Sustainable Energy without the hot air, building retrofit (insulation and air-tightness), heatpumps and electric vehicles form the cornerstone's of both significantly reducing the amount of energy we need to provide the same amount of comfort/utility and making it possible to power the remaining energy demand from electricity generated by sustainable energy.

The following graphics show's what the effect would be if each household in the study applied these measures:

1) All households switch current electric consumption to a 100% Green Electricity tariff:


2) 100% green electric powered heatpumps, Biomass and electric cooking instead of oil, gas and coal. For heatpumps it assumes replacing existing heat input with a heatpump with a COP of 3.0. See step 5 for a very basic application of building performance retrofit work.

Heatpumps form the cornerstone of supplying the remaining heat demand after retrofit in both Zero Carbon Britain and David MacKay's sustainable energy without the hot air. The performance of a heatpump is highly dependent of course on being designed, installed and controlled correctly.


3) Switch all petrol and diesel cars to electric cars powered by renewable electricity (Assuming mileage stays constant and an electric car performance of 4.0 Miles/kWh)

The ZeroCarbonBritain report from CAT suggests a reduction in the number of miles driven through a combination of increased use of pubic transport, walking, biking and better planning of where we live in relation to work/activities in addition to a switch to electric vehicles which are both more efficient than petrol and diesel cars and can be powered by renewable electricity.


4) Electric trains instead of planes:

In order to achieve the last 15% and still enjoy travelling long distances we would need a switch from flights to electric train journey's, the model here just assumes that the number of flight miles are replaced with electric train miles powered by renewable electricity and that the destination is reachable by train.



5) At least 120 kWh/m2.year primary energy for space heating and home electric.

Improving the thermal performance of buildings by adding insulation and improving the air-tightness should be one of the first measures applied and considered before or at the same time as any heating system changes as in step 2 above. The implementation of applying retrofit measures in the energy stack visualisation model here is only to set a maximum primary energy use requirement rather than to explore what's possible on a house by house basis which would give a better picture of the potential savings from retrofit work.



Powering Up with Renewable Energy

The ZeroCarbonBritain report goes into a lot of detail on how the remaining energy demand after applying power down measures can be supplied by renewable energy and also the need for storage technologies to manage the intermittent nature of a fully renewable energy supply. We didnt look into this as part of our study but it would be interesting to explore it in more detail in the future to answer questions such as: what scale of community energy projects such as community wind, solar and hydro should we be thinking of if we are to supply our energy demands after applying power down measures? and how much should we be thinking about energy storage in a more local context?

There's a lot of things that could be improved about the study. Rather than applying back of the envelope calculations on the effects of applying the various solutions to each house it would be better to look at each house in detail, carrying out a full detailed Carbon Coop home energy assessment for each house on how energy demand can be reduced by up to 70% through retrofit work.

Related links

OpenEnergyMonitor page on Sustainable Energy:
http://openenergymonitor.org/emon/sustainable-energy

The ZeroCarbonBritain report:
http://zerocarbonbritain.org/
Alice Hooker-Stroud, Centre for Alternative Technology, ‘Zero Carbon Britain (Energy)’

Sustainable energy without the hot air
http://withouthotair.com/

Carbon Coop
Charlie Baker's talk about carbon coop and 80% retrofit at the radical emissions reduction conference


Where next?
I would be interested to hear any thoughts on how to develop this work further, where it should go next. Feel free to email me if you have any ideas or would like to discuss: trystanlea at openenergymonitor.org
Categories: Blog

Testing KiCad PCB

Sat, 25/10/2014 - 19:54
We are always a fan of using open-source software wherever possible. A few years ago I briefly attempted to use open-source KiCad and gEDA PCB CAD software but found them very limiting, clumsy and buggy.

Recently there have been a raft of shiny looking browser based PCB design tools such as Circuit Maker and Upverter, these look very interesting; the online collaborative development opportunities are obvious and linking into the OctoPart's live component pricing, standard part library and BOM management tools could be a big time saver at the manufacturing stage. Maybe online tools will be the future, however I am a little reserved about having designs locked into a closed online platform.

In particular I have been keeping a close eye on KiCad developments after I heard CERN had got involved in the development. I was very impressed watching this video showing the newly developed KiCad intelligent semi-auto router in action:


I think it's time I gave KiCad another try! Today I managed to install KiCad and put together the RFM12Pi schematic and layout the board. Here's my experience:

I wanted the latest build to get the shiny new features, so I installed the development branch by adding the PPA to Ubuntu:

http://ppa.launchpad.net/js-reynaud/ppa-kicad/ubuntu

I installed KiCad build dated 16th July on 32-bit Ubuntu 14.04

I found I needed to add the line "export KIGITHUB="https://github.com/KiCad";" to my ~/.profile file to get rid of cannot find github footprint errors when running CvPCB (the program in KiCad which links the schematic parts to PCB footprints)

I followed the fantastic video tutorials from Contextual Electronics to help me get started.


1. KiCad Schematic Editor, net list must be manually exported to move to the next setp
2. Linking schematic parts to PCB footprints
3. Board layout the new interactive router was great (see video above)New router options
Update: the finished Kicad RFM2Pi V2.7 design is up on github:
https://github.com/openenergymonitor/Hardware/tree/master/RFM2Pi/board/KiCad_RFM12Pi%20V2.7
Obviously we have considerable lock-in to EAGLE PCB with our historic designs and learning a new software tool is always going to be a slow and slightly frustrating process, however I'm quite impressed that after about 5hrs I think I'm got the hang of basic KiCad functions. I will seriously consider using KiCad for new designs in the future. I think the increased effort will be worthwhile to enable us to be using a fully open-source bit of design software to design open-hardware, what do you think?
Thinks I liked about KiCad:
  • Interactive router, very impressed with this. Big time saver
  • More intuitive setup of default track widths and net classes 
  • How net and pin names are displayed in the layout editor 
  • How schematic symbols and PCB footprints are handled as separate entities, more intuitive than Eagle IMHO  
Thinks I miss moving from Eagle:
  • Have a live link between schematic and PCB, KiCad requires exporting and re-importing a new netlist each time there is a change in schematic
  • There are more ready made parts in Eagle libraries then there are KiCad part libraries, but I'm sure this will change. 
  • Being able to highlight all tracks on a particular net by selecting a wire on the schematic (maybe I've just not found this feature yet in KiCad?)
Categories: Blog

Emonhub installation/update, replacing the PHP raspberrypi emoncms module

Fri, 24/10/2014 - 11:58
From Paul Reed's post on the forums here:
http://openenergymonitor.org/emon/node/5986

Emonhub is now the recommended method of interfacing a rfm12pi to a local or remote emoncms install, and replaces the PHP and Python scripts which we have previously used.

Update: This blog post refers to installing emonHub on existing system, if setting up a new system downloading the ready-to-go pre-built RaspberryPi image is the easiest way to get started.

Thanks to Paul Burnell, the author of emonhub, installation of emonhub can be achieved via a command line, which clones an installation script to automate the installation process.

To install emonhub:

$ git clone https://github.com/emonhub/dev-emonhub.git ~/dev-emonhub && ~/dev-emonhub/install

If you have the raspberry pi module already installed, it's important that it is removed prior to installing emonhub, as only one software can use the serial UART the RFM2Pi is connected to at any one time.

To remove the existing module, and then install emonhub, enter the following command line;

$ git clone https://github.com/emonhub/dev-emonhub.git ~/dev-emonhub && ~/dev-emonhub/upgrade

You will notice that after running this command, that emoncms will stop updating, this is expected until the configuration file is updated as follows;

$ nano /etc/emonhub/emonhub.conf

Enter your emoncms read/write api key in [[[runtimesettings]]] and also enter your rfm2pi frequency, group & base id under [[[runtimesettings]]]
Save your settings, and; $ sudo service emonhub restart

Problems?
View the error log; $ tail -f /var/log/emonhub/emonhub.log

By default this is set to record 'WARNING', however this can be changed to either - DEBUG, INFO, WARNING, ERROR, and CRITICAL by editing the configuration file.

Paul

NOTE - This update will not orphan or alter your input processes, feeds, visualizations or feed data, as it only changes the way in which data is fed to emoncms.
Categories: Blog