Which Energy Monitor system to build?

This is my first post and I am looking to buy parts and build my first energy monitor. I have to choose between building an emonTx system or building something similar to the jarv.org setup. As far as I can tell, here are the advantages of each system. Help me choose!

>> emonTx advantages:

Simpler, great community of support (which I will need!)

emoncms interface looks better and easier to setup

Ability to easily add LCD down the road


>> Jarv.org advantages:

Uses ethernet; does not require a base station

Lower cost, since I don't have to build a base station

Lower power consumption (I assume), which is great since that's a main point of this exercise


fluppie007's picture

Re: Which Energy Monitor system to build?

Hi JP and welcome!

What I think is a cool configuration is a Raspberry Pi with the RFM2PI + emonTx and a emonGLCD if you like.

The cool thing about the RF part is that you can put the LCD where-ever you want and also you don't need a RJ45/network connection near your fusebox for the emonTx. I think it gives you more flexibility.

You also can extend these emon systems with all kind of nodes (Martin Harizanov's Funky sensor, Jean-Claude Wippler's JeeNodes) or you develop an add-on yourself :-). Anyway, I think that the Open Energy Monitor platform is a really cool, open and extendable one!

JP's picture

Re: Which Energy Monitor system to build?

Thanks Fluppie! You have convinced me that OpenEnergy is the way to go. Now the choice is between the RasberryPi and the NanodeRF for a base station. I know the Pi can act as a web server but I am not sure why this is a huge advantage compared to hosting with a remote server. What do you think?

I am concerned that the Pi may have more power consumption than the NanodeRF, important to me since this will be on 24/7. How many watts is yours pulling?

Which version of the Pi are you using? I am assuming B with 512MB since this comes with RJ45. Do you need the B with RJ45 in order to interface with the home network, or can the RFM2Pi connect to my home network too?

fluppie007's picture

Re: Which Energy Monitor system to build?

I would go for the Raspberry, it's easier to configure and there's a ready to go SD Card image :-).

To me it's handy, when the hosting company is down or my internet connection is down, my readings won't get lost. That's why I want my own local copy of emonCMS and I'll forward the analysed data to a remote server (built-in in the RaspberryPi module of emonCMS).

Yes indeed, I ordered mine 3 weeks ago from Farnell/Element14. It's indeed the B version with 512MB RAM.

I haven't measured it yet, because I'm feeding it from the USB port of my server :-). But this means, not more than 500mA thus maximum 2.5W. But with a 'real' supply model B can take up to 700mA, 3.5W.

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