The Answer is 42!!: How to design a simple light dark detector
photoresistor - Dark sensor with transistor - Electrical Engineering Stack Exchange
Dark Detector LED Circuit Using LDR
How to make Darkness Sensor Circuit using LDR to Control AC 220V or DC Load || DIY Circuit. - YouTube
I'm making a simple dark sensor project with a light dependent resistor (LDR) and I want to replace the LED with a buzzer but it doesn't work - Electrical Engineering Stack Exchange
Darkness Detector Circuit
LDR Darkness and Light Detector Sensor Electronic Circuit
light sensor / ldr dark sensor circuit - EasyEDA open source hardware lab