I have a water level sensor in which by varying the level of the water, an inductance change his value in a mobile coil. The sensor have the internal simple schematic like this (i don't know the value of the components)
The suggested working circuit use a Colpitts oscillator made by some HEX inverters, producing a frequency from 21 kHz to 25 kHz linked to the coil position and at the end to the water level by a provided lookup table.
I should read this frequency (level) by a micro, and I know how to do it, but in my project I used all the internal microcontroller timers. So, what I would ask, is if I can get around, using this variable inductance to produce a variable voltage to be read by the micro (avoiding to measure a frequency). And if it was possible avoiding a cascade of a Colpitts oscillator and a Frequency-Voltage converter (like the LM311).