We found this circuit in an Electronics Now from the 1990s. The circuit crashes when light strikes the sensor. Instead of the alarm a relay can be used to drive higher power devices.
Found in old documentation, this circuit uses components that are still common on the market. The...
This circuit activates a relay by activating one of a series of optical sensors that can be...
We found this circuit in a 1996 publication. Equivalent components can be tried, especially in the...