I have purchased a PT-1000 sensor to measure temperature. It's a RTD (resistance with temperature dependency). At 0 Celsius it's exactly 1000 ohms, and it raises its resistance about 4 ohms with each degree.
To measure the resistance I made a usual current divisor with a resistance of 1k. After reading the voltage I get the temperature from a look-up table. It works really well when it's calibrated, but the problem is the power supply has to be super stable, because if instead of 5.0 volts I got 4.98, the error is big.
I have to make a design independent from the power supply because I can't calibrate it each day. Any experience? What do you recommend: Wheatstone bridge, voltage reference, current source, ...?