This circuit was found in the Electronics Experimenter Handbook of 1961. The circuit uses door sensors and others. It is powered by 12 V from the car battery.
This circuit was found in a 90’s 303 Circuits. The components are from the period and the heating...
Found on Popular Electronics this circuit has variations found throughout this site and section....
The transistors in this circuit from a 1994 technical publication may be BC548 and the 12 V supply...