New to openHAB, looking for suitable relays and sensors


i finally decided to start tinkering with home automation and i want to use openHAB. I have a server, network etc setup, but i need some help choosing the first items for the automation-part :wink:

I need a relais and a temperature sensor. They stay outside, so they should be able to deal with temperatures from -25°C to +60°C (or something along those lines). They wont sit in the pouring rain, but i cant guarentee absolute dryness or a certain humidity. Finally they should use some kind of wireless connection that works with openHAB and is very reliable (the life of 4 turtles is on the line!).

Do you have any suggestions on what technology, brand or model i should use here? I searched the board, and will continuing to do so, but i dont think that i can pick out the best device for my requirements for myself.

Thanks in advance for any tips! :slight_smile:

You’ll need to specify range here to narrow the field. 10m, 100m, through walls ? Also power options - battery, or is mains available at sensor location? What load does the relay have to control - a battery powered LED, or a high power heater?

Ah ok, makes sense :slight_smile:

The range depends on where they are attached to the ethernet, i guess. The shortest would be 25m, almost a direct line, with 2 “walls” (1x stone and 1x some kind of greenhouse). If i have the wireless receiver near my server its more like 40m with 4 walls, kinda hard to get a signal through. I guess i will place the receiver as best as i can.

I have mains avaiable and it would be great if no device would run on battery, since batteries and very low temperatures (winter) arent a perfect matchup in my experience.

The controlled load is about 100w (at 230v, reptile warming bulb). The bulb comes with a controlling device that should guarantee a softstart, i never tested if that works though.

Sounds like a job for a Sonoff, a WiFi mains control relay with options for temp and humidity sensing. You need a little technical skill to modify one for local control rather than via chinese cloud

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Looks interesting. Do you know a solution that dont needs flashing with a different firmware though? :wink:

The Sonoff devices have an operating temperature of 0-40°C, if those datasheets are correct. The Sonoff devices i found so far seem to be indoor devices, if i am not mistaken …?

Yep. Obviously you can put them in an enclosure.
I wouldn’t expect low-temperature operation to be an issue in practice, the device is powered off mains and will self-warm to an extent.
It’s more likely to mess up at high temperatures, there aren’t many pieces of non-military grade electronic kit verified to work at 60C

If this is all a worry, it might be time to rethink it as a wired solution, all control and switchgear indoors and just a pair of wires to a remote temperature sensor.

Yeah maybe you are right. I will look deeper into those Sonoffs now, but it seems i need a bit of equipment to flash the firmware. Thank you for the tipp though :slight_smile:

I’d not expect any problems outdoor, as long as you protect the Sonoff from rain and high humidity. All further details (including setup instructions) should be described here: