Try to never try resistive sensors. It is reaaly wrong way. I try to bult few resistive. No way.
I try to buld some inductive. Yes, it's possible, but lot of analog parts, difficult to calibrate. No way too.
Capacitive senors is most reliable and has a simple digital schematics.

Good luck you on your way)

PS: here is my own sensor http://vegimatics.com/products/current/
want do discuss - wellcome)

RF_CH bits are used to select channel. Channel number and frequence calculated like this: F = 2400 + RF_CH.

And some usefull table.

@thucar
Hello, i'm not sure it is to good idea to public links here, but there is my personal website where is some sensors examples in sensors history page http://vegimatics.com/products/history/

And of course, we can discuss here some interesting for you things)