Essence of open source

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

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

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.

Ubuntu podcast Interview

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:

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

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:

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

Home Camp 4 presentation slides

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 4It 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

Home camp 4: London 29th-30th Oct

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:

See you there, Glyn.

Introducing Megni

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

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

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.