Interesting conversation. I can't help but throw a fly in the ointment, as they say. Have you calculated the cost of all this additional infrastructure? Wouldn't it make more sense if you are going to this level of implementation, to go with a standard system like zWave/ZigBee modules, or something else on the open market? It's plug and play into any existing standard home electrical infrastructure. In addition, they are all fully certified products for home use and limit your risk of liability should you have an electrical fire or anything else that could be attributed to your self built system.

Don't get me wrong, I like MySensors and am using some point solutions that make sense for me. I myself have contemplated putting in a full blown MySensors environment for control of devices, but I'm having a hard time justifying the costs and risk in doing so. In addition, I won't plan on staying in my house forever, so the potential resale could be more difficult with a non standard infrastructure.

Just some thoughts to consider. Would love to hear some additional ideas on the topic.

I don't believe you can put both inbound and outbound mqtt messages in the switch definition. This is what creates the infinite loop since you are both sending and receiving on the same message topic. Every time the broker receives the message, it publishes it out to all subscribers. Since your switch item is also a subscriber it picks it up again and the loop continues.

Use only inbound in the definition then either a rule and/or proxy item to handle the outbound command. Set your rule definition "when item received command". That way it will only fire when you click on the switch item in openHAB. If you use any other option, ie. received update or changed, it will also continue the infinite loop.

Hope this makes sense.

Is your MQTT binding set up in OpenHAB.cfg? What are the settings?

Hey everyone. Been following this as I'm very interested in having this functionality with the Arduino's. I'm a newbie and have very limited knowledge with anything electrical, so forgive my ignorance. How is this problem any different than what the X10/ZWave/etc. solutions have already overcome years ago? I have an X10 wall socket that does very similar switching on/off of one socket. All the components are built inside the socket, putting the control components and the high voltage very close together. The wall switches are another example. They always have some current running thru them even when the light is switched off, to detect the signal. Again, forgive my lack of understanding how all this works, but it seems like this may not be as big of an issue as I'm reading here. Thanks.

Here is a page on the message structure. It's the same as the Serial API. There is also a list of all the subtypes.

http://www.mysensors.org/download/serial_api_15