Complete Beginner with MySensors - questions about relays, MQTT and OpenHAB

[HenryWhite]

Hey guys,

I'm from germany and started one year ago to automate my house with OpenHAB. One focus I set was to get everything done as cheap as possible.
Currently I have the following things (among others) connected through OpenHAB on a Raspberry Pi:

• Ambilight
• XBMC (Kodi)
• 433Mhz Wall sockets
• 433Mhz Garage Door "Hack" (old remote control + relay connected to RPi)
• 868Mhz temperature/ humidity sensors
• radiator thermostats
• (RGB) LED Strips
• Homeserver (WOL)
• PC (WOL)

But now I discovered MySensors and this website seems to be what I have looking for lately! Not only are there nice tutorials, the smart home solutions presented here are also very cheap to realize).
Especially I want to get rid of 433Mhz connections, because they are unreliable and don't work everytime (more than that, I even can't switch on multiple 433Mhz Wall sockets at the same time)

I just ordered some Arduino Pro Minis, Motion sensors and relays, so here is my question:

Let's say I want to hook up a LED Strip to a relay and control this relay by radio with OpenHAB.
Then I would need to:

1. Hook up the relay to an Arduino with connected NRF24L01+ 2.4GHz Wireless Transceiver
2. Build an MQTT gateway with another arduino
3. Use this tutorial to connect it to my OpenHAB Server --------> Can OpenHAB only display the status values or can it actively send commands to the MQTT gateway? (sending commands would be necessary if I want to control the relay through OpenHAB)

Is this correct?

Thank you

[tomkxy]

@HenryWhite said:

Can OpenHAB only display the status values or can it actively send commands to the MQTT gateway?

Yes, you can send commands via MQTT. Have a look at the OpenHab MQTT binding doc. https://github.com/openhab/openhab/wiki/MQTT-Binding

[Dwalt]

@HenryWhite You do not need to use MQTT for your gateway, you can use the serial or ethernet gateways as well. You may find them easier to get started with MySensors.

[HenryWhite]

@tomkxy @Dwalt thank you for your answers!

I read that it's better to use the MQTT than the serial gateway - is that the case? and when yes, why?

thanks!