This circuit is from General Electric from the 80s, using a relay with high current contacts (20 A). The transistor admits equivalent, and any phototransistor can be used as a sensor.
This high current circuit using a MOSFET and an operational one was found in a documentation from...
In this circuit, the integrated amplifier used is uncommon today. The circuit is from an American...
The sensor can be made using two bare wire or two screen with a piece of tisse between them. One...