This long interval timer was found in the September 1976 issue of Radio Electronics magazine. The output can be used to control a relay. The circuit achieves timings of up to 14 hours.
This circuit came out in an English publication of 1976, but it can be easily assembled using...
When light fails to focus on the sensor, a common photo-transistor, the relay closes its contacts....
This traditional clock circuit with common CMOS components with discrete logic functions was found...