This optical sensor circuit for a robot was found in the March 1986 issue of Radio Electronics magazine. It controls two motors according to signals from optical sensors or couplers.
Any general purpose PNP transistor such as the BC558 can be used on this circuit from an old...
This circuit is from a 1965 General Electric hobby manual. The circuit can be assembled with...
This circuit was found in a Maxim documentation from the 90s. It is valid for the lower income types...