How to get an energy value read by a rtl-sdr USB device into openhab?

Setup, Configuration and Use Beginners
1

Hi everybody,
I’m running OH 1.83 on a Raspi with a Tellstick to read all the temperatures and control the switches in my house. Now I bought an efergy e2 ir wireless electricity monitor to read the pulses from my energy meter. To get the energy readings into my raspi I bought a DVB-T USB dongle with SDR support. I added RTL-SDR together with a decoder (RPI_Efergy) to read the energy data which will be send every 30 s. This value for the moment will be written into a text file. It looks like this:

Efergy Energy Monitor Decoder
04/24/16,14:12:51,1079.000000

Now my question, what will be the easiest way to get the energy value, in this case 1.079 kW, into openhab and show it as a live value and add as a persistence ???

Thanks for any advice.

Udo

2

Hi Udo,

I do something very similar with lacrosse temperature sensors in my house.

What I do at the pi with the sdr is pipe the raw input to a mqtt topic.

eg
on the pi (i use the screen app so you can disconnect your terminal)
rtlamr -format=csv -quiet=true | mosquitto_pub -h 192.168.0.210 -t private/water -l &

Then I have a python script which parses data on that topic (private/water) and does any processing you may want, and then publishes those readings on a topic such as:

sensors/garage/temperature or sensors/kitchen/temperature, etc

Then use the mqtt binding to get those values into openhab.

3

Thanks for your suggestion but it seems to be too complicated for a beginner to realise.
The file with the values is already on the Raspberry Pi where OH runs.
What I need is a script which can open the file and parse the data (energy value) into a number item

4

maybe you could solve this issue by using the exec binding, and something like the program grep to retrieve the info.

5

Hey!

How is your progress with the efergy e2 classic?
Where did you buy the dongle? I am looking to integrate and create a binding for the unit for OpenHAB2.

Thanks for answering,
Brynjar

6

Hi,
I didn’t continue with the Efergy because I installed a Solar plant on the
roof and get the values now from the inverter instead.
The dongle you can find everywhere on eBay and Amazon for around 6 Euros.
Just take care that the DVB-T dongle has SDR support.
It’s multi-usable not only for receiving values from a 433Mhz sensor but
also to track the air traffic around where you live or get the latest
satellite pictures from a Russian weather satellite.
Anyhow good luck with creation of the binding. Will test it when I migrate
to OH2.
BR,
Udo

7

Did you make any API for the USB-dongle so that it is easy to send and receive messages to/from it?
(Since this is some schoolwork, I don’t have time to do it myself)

Thank you!

8

No, unfortunately I didn’t come so far otherwise it would have been easy to
get the values into openhab.
I just got the values written into a text file and got stuck there.
On this website you will find most information to start with:

BR,
Udo

9

As an fyi.

I use a SDR to read the water readings from the meter outside my house.

I have ended up piping output of the sdr software into mqtt_pub. This gets the reading to mqtt, then trivial to get it to openhab.