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.
This low frequency circuit was found in documentation from the 1980s. The values of R and C...
The 4528 is a dual-retriggerable monostable that needs only the timing network formed by R and C...
This ttransistor test was found in a 1987 documentation. It is a simple oscillator that allows to...