Beginner help choosing temperature and humidity sensors

I’m just getting started with OpenHAB and I need some help choosing hardware.

I would like to have at least three sets of temperature and humidity sensors - one outdoors, one in the house attic, and one in the (detached) garage attic. I have power and wired Ethernet in the garage.

My current thought is to have a Raspberry Pi or Arduino to connect the sensors to. I’ve looked at various sensors and various protocols (I2C, OneWire, etc.) but I don’t understand how far from the computer the sensors can be located.

Ideally the computer would be located in the house with wires running to the sensors, which would be about a 75 foot run of wire to the sensor.

OpenHAB and Mosquitto are running on a Synology DIskstation.

Any help or suggestions are appreciated.

What about Sonoff TH sensors? Cheap and display Temp, Humdity and can control power. Youll need WIFI though

esp8266 + Tasmota + DHT22 or SI7021 or BME280 etc


Is the way i went. Used espeasy with dht22. For inside and on my weather station part used bme280

Well you can either put up a SINGLE central Pi and run all wires there, but sounds like your sensors are to be located far away from each other (and thus far away from any central unit, no matter where you place it), so running those wires will probably be cumbersome.
Also, a Pi has digital inputs only and AFAIK there’s no OneWire or other humidity sensor to do A/D conversion (for temperature yes but not for humidity), therefore to deploy ESPs (or Sonoffs which essentially is just a prepackaged ESP) and to use WiFi is probably the best option. Wires to transmit power you’ll need anyway, though.

That was my main reason for deploying the esp. was due to the fact that my pi has only DI and I use AI as well.and Also the distances of the sensors to my pi. So esp was the better idea. I had to deploy a wifi system that caters only for my home automation.
But thats me . You can run it on your home wifi system . You will have to get power to the esp or run them on battery system but then you still end up having to go and change batteries once in a wile.

If you can deploy wires then deploy Ethernet cables and set-up arduinos with ethernet shield for your sensors.

You can also use a POE (POWER over Ethernet) injector near your pi and router and pick up the power for the arduino from the Ethernet cable with one of these:
POE injector:

POE splitter:

If you can’t pass Ethernet cable then over the long distances you mentioned, you will struggle to get a reading from your deployed satellite sensors. and I would recommend the Wifi solution as mentioned above by @dastrix80, @Olymp, @allen and @mstormi

Don’t you ever run WiFi devices on battery, WiFi is not optimized for it and will drain any battery fast (well unless you put your old car’s 95Ah one up the attic :-))

If you have to run on batteries then I highly recommend:

and especially:

I have had these for more than a year now in each room of the house without changing the batteries
Reporting hum and temp every 5 minutes

LOL . No I have breakout boards that I have made that supply my esp with power. From a 12v supply that I ran trough my roof cavity .
Battery always tend to leave you with a bad tast in your mouth.

Yeah, they don’t taste very good :laughing:

Thanks for your help.

I wasn’t aware of Sonoff and at first they looked promising. However I noticed that they have an operating range of 0ºC-40ºC (32°F-104°F). I live in Texas where the ambient temperature sometimes exceeds 102 and the temperature in the attic is well above that value. I’ve also seen temps in the low twenties in the winter.

However I noticed Sonoff uses the ESP8266 and some ESP8266 chips have a much wider operating temperature range so I’m looking to see if I can find a similar board that will work for me.


Esp are good. And you can use espeasy on them also. Nice and easy setups