Found in 1980s Electronic Engineering, this circuit uses common phototransistors as sensors. The circuit is CMOS using an integrated 4011.
This circuit was found in a former Popular Electronics. The timing is set on the potentiometer and the...
This fast-acting circuit uses a 555. We found it in the November 1992 Radio Electronics magazine. The...
This circuit was found in the Spanish magazine No longer in existence, Mundo Electrónico, in a...