My solar collector controller has three NTC 10K temperature sensor and one T1000 type.
With my multimeter I can measure about 4V and 1V (depending on the temperature) DC between the two wires for the NTC sensors.
(The T1000 measures between 60 and 50 mV DC depending on temperature, a later issue)
Now I want to read this sensor in parallel to my heating system, without disturbing it too much with my Arduino. Accuracy to about 1°C (about 25 Ohms/K, non-linear) is fine.
I was thinking of just analogread the sensors but I measure that the NTC sensors have common positive.
Is there hope and can go into the world of optamps or does this mean I will end up with both common ground and common positive which sounds really bad.
Please help me out here.