Hi,
I was wondering if Emoncms plans to support third party electricity monitors such as CurrentCost. I found this post http://openenergymonitor.org/emon/node/1418 but it seems like it's a DIY affair. As most of these monitors communicate over serial is there scope to share some code between them?
A while ago I ported a cheap Maplin electricity monitor to Linux (https://github.com/jpsingleton/Raspberry-Pi-Electricity-Monitor and https://unop.uk/dev/raspberry-pi-electricity-monitor/) and I'd love to integrate this with Emoncms. It looks like there are a couple of options:
- Create a standalone project that reads the data and posts it to the Emoncms API
- Integrate the python serial reading code into https://github.com/emonhub/emonhub/
I'd prefer the second option and it would be great if emonHub could support a range of monitors in addition to the native open energy monitor hardware. There seems to be a lot of shared logic as most are very similar.
Anyone have ideas / preferences on this before I open a pull request and get coding?
Cheers
Re: Support for third party electricity monitors
I think a current cost (or similar) interface could be a good addition as there are many of those out there, I would be happy to assist with the emonhub side of things if it helps. However emonHub is about to under go some quite heavy changes so beware not to invest too heavily into integrating with it in it's current form. I can't be absolutely sure on the full extent of the changes required just yet. but thought you should know.
Paul
Re: Support for third party electricity monitors
OK, thanks. It looked like things might be in a state of flux with new projects like emonview. I'll see about integrating my python code into emonhub as I think that's currently the logical place for it.
I believe a good long term strategy would be to de-couple the raspberry pi software from the open energy monitor hardware so that commercial off the shelf electricity monitors (and maybe smart meters in the future) can be used as well. Not everyone has a power source near their meter.
This project seems to be a good example of a robust raspberry pi python daemon:
It uses advanced features such as the watchdog available on the pi.
Re: Support for third party electricity monitors
The emonTx V3 can run from batteries of no power source is close by. It had a 3 x AA battery holder on board. But yes I agree using emonhub to support other energy monitors and being able to forward data to other services would be good in the spirit of openness! I'm all for it.
Re: Support for third party electricity monitors
Ah, I didn't see that. Do you have data on how long they last? Can the voltage be measured from a separate location and combined with the current measurement or does the timing need to be very accurate?
It looks like someone else has done the same as me so there is probably a demand for standard server side software to use with cheap hardware: http://electroncastle.com/wp/?p=1808
Re: Support for third party electricity monitors
You could monitor the voltage at a separate location, but that would limit your measurement to apparent power only. Real power (and by inference import/export) and power factor are not available as precise timing between corresponding samples of the wave (at approx 2500 samples per second) is required, and the samples values must be transmitted between locations too!
Re: Support for third party electricity monitors
I've updated my code to post to the emoncms API. As this monitor has been discontinued I decided not to integrate into emonhub.