I am trying to get more precise temperature value from PT100 ( 2 wire ) sensor with Arduino.
Here's how my circuit looks like :
When the sensor is about 20 °C I get a value on A5 pin that is 432 and when the sensor is about 30 °C I get a value on A5 pin that is 440. As you can see this is a very small range ( 432 - 440 ) and I can't get a precise reading on my temperature sensor.
What can I do with my circuit to get a more precise reading ? ( i.e. larger analog signal range like from 100 to 1000 )
Maybe I could somehow obtain the resistance of PT100 and with some math formula get the temperature?