Store temperature in a file, then acces that file via wget

Hi everyone,

I’m not sure if I can exactly describe what I want to do but I will give it a try.

I have a Home assistant setup (Qnap Nas, WM with Ubuntu) with a iPad as a main control screen in my living room.
Next to the iPad is my thermostat (Rooted Toon).
I don’t want 2 ‘screens’ in my living room. I want to put the thermostat somewhere I don’t see it. Like in the attic or in a utility room but then the measured temperature isn’t the right temperature of my living room. Unfortunately the thermostat is needed for controlling my Heating system via open therm. The thermostat has some good algorithms for heating and stuf so I need that thermostat.

So my thermostat is Rooted and I have full control (linux os).
It is possible to fool the thermostat by finding a way to put (and update) an external temperature (from my Fibaro Smoke detector or a DHT11/arduino/ESPHome) into a file on my toon (for example in /var/externaltemp). The file should contain only one line, the temperature. I think it must be in this floating point format xx.yyyy so for example 28.345

So I need to put the temperature from a sensor in HA in a file, so I can write a script like wget http://IP_HA/file that the thermostat can read and use so it won’t use it’s internar sensor.

I hope you can understand what I want and can help me a little.