The most common type of motion detection sensor is the passive infrared (PIR) sensor. Other sensors for motion detection include ultrasonic and microwave sensors. Although they employ different technologies, they all detect motion which is then converted into electrical signals. If the motion is confirmed, they can then trigger different responses, such as activating lights or alarms.

The best choice of sensor will depend on the requirements and intended use of the sensors. Passive infrared (PIR) sensors are the most common and low-cost option. Ultrasonic and microwave sensors are more expensive, but they also have more capabilities, such as longer detection ranges and the ability to work through obstacles.

Passive infrared (PIR) motion detection uses sensors to detect changes in infrared radiation emitted by people or objects in their field of view. If an object or person moves in view of the sensors, it will create a change in the pattern of infrared radiation, triggering the sensors to activate. Because PIR motion detection is reliable and low-cost technology, it is often used in security systems and lighting controls.

3D motion detection is used in many different fields, such as surveillance, virtual reality, robotics and gaming. It typically uses advanced technologies, such as depth sensors and stereo cameras, to track motion in three dimensions, in multiple directions and depths.

Passive infrared (PIR) motion detector sensors may struggle to detect motion through glass, though some sensors might be able to detect temperature changes on the glass due to nearby motion. Although lighting conditions, camera angles and glass type may affect the accuracy, security cameras with motion detection capabilities can typically detect motion through glass. You should however be wary of visual distortions such as reflection and glare.

Typically, short-range indoor sensors can detect motion up to a range of 10-20 feet (3-6 meters), while long-range outdoor sensors can detect motion at distances of 30 feet (9 meters) or more. This is based on the average passive infrared (PIR), ultrasonic and microwave sensor, but exact range details will depend on the specific make and model of sensor.