PIR Motion Sensor Module (HC-SR501)
Passive Infrared Detector for Arduino and DIY Projects
This PIR (Passive Infrared) sensor module is a cost-effective motion detector that senses human presence by detecting changes in infrared radiation. It's widely used in home automation, security alarms, and automatic lighting systems [citation:4][citation:5].
Simple Motion Detection - Detects movement up to 7 meters with a 120° field of view
Adjustable Sensitivity - Onboard potentiometers for range and delay time control
Operating voltage: 5V to 20V DC (5V recommended for Arduino) [citation:5][citation:6]
Use the potentiometers to adjust detection distance and output hold time
Sensor requires a warmingup period of 12 minutes for stable readings
Technical Specifications
| Parameter | Value |
|---|
| Model | HC-SR501 [citation:5] |
| Detection Range | Up to 7 meters [citation:5][citation:6] |
| Field of View | 120° [citation:5][citation:6] |
| Operating Voltage | 4.5V to 20V DC [citation:2][citation:5] |
| Output Signal | 3.3V TTL (HIGH when motion detected) [citation:5] |
| Current Draw | <65mA (low power consumption) [citation:6] |
| Temperature Range | -20°C to +80°C [citation:5] |
| PCB Dimensions | 32 x 24mm [citation:6] |
= Pin Configuration =
| Pin | Name | Connection |
|---|
| VCC | Power | 5V (or 4.5-20V) [citation:5] |
| GND | Ground | Connect to GND |
| OUT | Output | Digital signal to MCU pin [citation:3] |
> Connect OUT to Arduino digital pin (e.g., D2)
Use repeatable trigger mode for continuous motion detection
Output is 3.3V - safe for 5V Arduino inputs [citation:5]
Keep sensor away from direct sunlight and heat sources
Wiring to Arduino
- VCC → 5V pin
- GND → GND
- OUT → Digital Pin 2 (or any other) [citation:7]
Applications
- Security and burglar alarm systems [citation:7][citation:12]
- Automatic lighting and streetlights
- Occupancy detection for energy saving
- Arduino and ESP32 interactive projects
- Industrial automation and safety systems
Easy Integration Simple 3pin connection with digital output
Versatile Use - Works with Arduino, ESP32, and Raspberry Pi
√ Onboard lens for improved detection
√ Adjustable delay and sensitivity
√ Ready for breadboard and prototyping
Troubleshooting
No motion detected:
- Allow 12 minutes for sensor stabilization after poweron [citation:3]
- Adjust sensitivity potentiometer
- Check output pin wiring
False triggers:
- Reduce detection range via potentiometer
- Avoid vibrations or heat sources near sensor
- Use repeatable trigger mode (H jumper)
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