Low Resistance value measurement

[Charles Linquis]

You could make a voltage divider with another resistor, and then use the A/D converter to measure the voltage at the junction.

[Leonzio]

Thanks for suggesting, but I think this would require too current or would provide a very limited resolution due to the low value of the resistance to measure.

I think I should put some sort of amplifier in the middle, and this is a schema I'm looking for.

Regards
Leo

[Charles Linquis]

Why will it take too much current? if you put a 200 ohm resistor in series with the 330 ohm sensor, the total is 530 ohms, less than 10mA of current at 5V.
Unless you are battery-powered, that shouldn't be too much.

You should be able to get plenty of resolution with this arrangement.