Found in a Popular Electronics from the 90s, this circuit uses components that are still current. The circuit triggers the vehicle's horn. The sensors can be increased in number.
Found in a Motorola manual from the 1980s, this circuit uses components from the era. The circuit...
This circuit, which may have more inputs, consists of an optical OR gate using common...
Suggested by Amperex in a 1968 documentation, this circuit is based on TAA370, an integrated circuit...