This is the receiver for the earlier system published in the August 1988 Radio Electronics magazine. Optical capabilities can be used for extended range.
This low power circuit can be powered with voltages from 1.8 V. We find it in a 80s Hands On...
This 13.8 V transistorized power supply with a current capacity of 20 A has a protection system...
In this 2002 circuit, we have the activation when the reservoir is empty and shutdown when full....