What Is the HC-SR501? PIR Motion Sensor: Specs and Uses
The HC-SR501 is a PIR (passive infrared) motion sensor module. It detects the change in infrared emitted by a warm body's motion; on motion its output goes HIGH (3.3 V). Two pots set sensitivity (~3–7 m) and trigger time. It only detects motion (not a stationary body); at power-on it needs ~30–60 s to stabilize.
The HC-SR501 is a PIR (passive infrared) motion sensor module. It detects the change in infrared emitted by the motion of a warm body (a person/animal) and produces a digital output. For the concept, see what is a sensor.
What is the HC-SR501 used for?
Motion-triggered lights/alarms, automatic doors, presence detection and energy saving. When motion is detected the output (OUT) goes HIGH; two on-board pots set the sensitivity (range ~3–7 m) and the trigger time.
Specifications
| Parameter | Value |
|---|---|
| Type | PIR motion sensor module |
| Output | Digital (HIGH on motion, 3.3 V) |
| Supply | ~4.5–20 V (on-board regulator) |
| Range | ~3–7 m (adjustable) |
Watch out
A PIR only detects motion (not a stationary warm body). It needs ~30–60 s to stabilize at power-on. The retrigger jumper decides whether the output re-triggers while motion continues. Temperature and air currents can cause false triggers.
Equivalents
- AM312: a miniature 3.3 V PIR.
- RCWL-0516: a microwave (radar) motion sensor.
- HC-SR505: a mini PIR.
Find it in our catalog
Use the HC-SR501 search.