This PIR Motion Sensor is great for detecting anyone in the vicinity of your sensor. With a detection range up to 6m, these are great for adding user detection to any project, and are often used in automatic room lighting, automatic doors, and security systems.
This sensor includes 2 potentiometers to adjust the delay to switch on, and to adjust sensitivity.
A PIR (Pyroelectric ("Passive") InfraRed) Sensor is used to detect the changes in the differences in infared radiation such as temperature. Common uses are for PIR sensors are human detection systems that compare a static temperature of a background to changes in front of the sensor. This change in temperature produces a corresponding varying output voltage.