VOUT + R1 ref meaning

Hi,

I have a shelly 1 pm plus and an addon, and a thermistor NTC (24 kohms at +5 degrees, 10 kohms at +20 degrees)

The doc has this ratings https://kb.shelly.cloud/knowledge-base/shelly-plus-add-on

So it seems my thermistor is out of range, right ?

I was hoping to more or less follow the setup described here : https://kb.shelly.cloud/knowledge-base…-photoresistor-

Now I'm trying to understand a bit deeper how things work : is R1 here an internal resistance of the addon ? If so, do we know its value ?

I tried to wire the thermistor between GND, ANALOG IN and VREF + R1 OUT and got some voltage readings around 6v in Shelly UI, but not very stable, changing constantly between ~ 5.80 and 6.20v (at a 17 degrees place).

Thanks !

Actually I read the add on characteristics again and found this mention :

Supported sensors

• Up to 5 DS18B20
• Single DHT22
• NTC resistors with 10 kΩ nominal resistance and β=4000 K

I'm not sure if my thermistor qualifies with this requirement but it doesn't look too far off 🤔

So I now have a bit of data to share, and the results aren't really great (the voltage difference being quite low so accuracy wouldn't so good I guess).

voltage at around 18.1° : ~ 6.2v

voltage at around 5.5° : ~ 7.4v

temperature comes from a ds18b20 sensor really close to the thermistor

Any idea if I could improve a bit on this ?