flotulopex, I have used the POLOROID sensors in the past which are made the exact way these sensors are made.(I think they bought the patend rights). POLOROID used to have a kit for the sensors and maybe still does. I have bought the sensors you show below directly from the manufacture SensComp here in michigan, However the ones I purchased have the excitation and receiver electronics on board. They are only about 1/4 of an inch thicker. I wouldn't bother trying to build the excitation and receiver electronics for a sensor like this as the sensors only cost about $50 complete. Log on to Sencomp's website, they make analog output as well as digital output sensors.

Dave Purola,
N8NTA