وحدة مقاومة ضوئية معتمدة على الضوء. KY-018.

Plugged this into my breadboard and it immediately responded to my hand shadow. The analog readings are smooth, perfect for a simple night-light project I'm building.

Got my Arduino project detecting dawn and dusk in no time just by hooking up GND and VCC, and the analog signal is surprisingly steady even in dim room light.

Took me about two minutes to wire the GND and VCC pins to my Arduino, and the analog output shifts smoothly as I move my hand over the sensor. It's dead simple to read light levels from the microcontroller without any extra components. Exactly what I needed for a basic ambient light project.