Peel from the case to the element. Follow the readout through this conceptual model.
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Drag to rotate; pinch to zoom. With the view focused: arrow keys rotate, + / − zoom, 1–3 choose a layer, Home resets rotation and zoom. Step advances to the next layer; Reset returns to the case and default view. Layer buttons select a view directly. The page does not move on its own.
The Fresnel lens divides the detection area into zones. [PIR Motion Sensor (HC-SR501)]
Teaching view: The white Fresnel dome sits over the green board. The lens defines the zones in which the sensor detects changing infrared radiation.
The Fresnel lens divides the detection area into zones. [PIR Motion Sensor (HC-SR501)]
Teaching view: The white Fresnel dome sits over the green board. The lens defines the zones in which the sensor detects changing infrared radiation.
The module provides a digital motion state. [PIR Motion Sensor (HC-SR501)]
Teaching view: The green board carries a dark controller and blue and yellow adjustment blocks. The controls change sensitivity and how long the motion output stays on.
PIR sensors detect motion by measuring changes in infrared radiation from warm bodies. [PIR Motion Sensor (HC-SR501)]
The output reports infrared change rather than identity or distance. [PIR Motion Sensor (HC-SR501)]
Teaching view: Two tan tiles beneath the lens represent the sensing elements. The lens directs infrared radiation onto them. When a warm body moves across the detection zones, the radiation heats the elements by different amounts. Changes in their temperature create a small electrical signal, which the board amplifies and uses to switch the motion output on.
Explode separates the conceptual layers; X-ray makes the case translucent. External package dimensions follow the model specification; internal teaching geometry is conceptual, not to scale, and is not manufacturer CAD or a wiring diagram.