Name two sensors which would be used in a burglar alarm system

1. Passive Infrared Sensor

This sensors type is passive in a way that it doesn't radiate its own energy. Instead, it detects the infrared light radiating from objects. This way, it can detect whenever there's a human or another living being in its field of view.

2. Photoelectric Beams

This is also another type of motion detector, but it doesn't work similarly to the others. For one, it doesn't have a coverage area. It only forms a fence, which triggers the alarm if broken.

It consists of two separate parts that form a sort of a fence made of IR beams. When someone steps into the beams, between the two parts, they trigger the alarm.

looking away, slouching, not focusing

explanation: