This circuit works with the previous two by demodulating the signals received modulated in FM. The circuit is from the Radio Electronics magazine of December 1992.
November 2016 - Already available from Mouser Electronics on Texas Instruments' new DS280BR820...
This circuit is from the 80's component manual itself, but can be applied to more modern...
We found this circuit in the June 1992 issue of Radio Electronics magazine. The sensor is a common...