Hi Leonzio,
This is my first time as a registered user so I hope the file attachment works.
Providing your finished product is not exposed to ridiculous ambient temperature extremes, the suggested circuit should be accurate enough for your needs.
As we cannot measure resistance directly with any microcontroller we can solve our problem with Ohm's Law to change our resistance variable (your sensor) to a voltage variable.
Using the suggested circuit we can pass a fixed, known current, eg 10mA,
through the sensor and, using Ohm's Law, we now have a voltage to present to the microcontroller A\D input which can be measured and scaled to suit our needs. Using your values of resistance we will have a range of 0.86V to 3.30V if VR1 is set to pass 10mA through the sensor.
If you require any more help with the circuit or the software please do not hesitate to post a reply.
Regards Mike B, from Australia.
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