Item specifics
Description
HC-SR501 PIR Motion Sensor Module Product Overview
The HC-SR501 is an automatic control module based on infrared technology, featuring LHI778 pyroelectric infrared probe design with high sensitivity and strong reliability. The module is equipped with the BISS0001 sensor signal processing IC for stable performance and a wide operating voltage range. It detects infrared spectral changes emitted by the human body to achieve automatic sensing control, widely used in various automatic sensing electrical equipment, especially battery-powered automatic control products. Multiple specifications are available, allowing users to choose different sensing distances, delay times, and trigger modes based on actual requirements.
HC-SR501 PIR Motion Sensor Module Key Features
The HC-SR501 supports a wide DC voltage input from 4.5V to 20V, with a quiescent current of less than 50μA, making it ideal for battery-powered devices with its ultra-low power consumption. The output level is high 3.3V / low 0V, easily interfacing with various circuits. Trigger modes are selectable via jumper: L for non-repeatable trigger, H for repeatable trigger (default H). Delay time is adjustable from 0.5 to 200 seconds (customizable from fractions of a second to tens of minutes). The default blocking time is 2.5 seconds (customizable from fractions of a second to tens of seconds), effectively suppressing various interferences during load switching. The sensing angle is less than 100 degrees cone angle, and the sensing distance is adjustable via potentiometer: clockwise rotation increases distance (up to ~7 meters), counterclockwise decreases it (to ~3 meters). Operating temperature range is -15℃ to +70℃. The sensing lens diameter is 23mm (default), and the PCB dimensions are 32×24mm.
HC-SR501 PIR Motion Sensor Module Applications
The HC-SR501 PIR motion sensor module is widely used in security products for intrusion detection and alarm systems; interactive toys and devices; automatic lighting and stairway switches; industrial automation control; smart home applications for automatic control of air conditioners and TVs; as well as automatic doors, electric fans, dryers, and various automatic sensing electrical equipment.
HC-SR501 PIR Motion Sensor Module Key Advantages
The HC-SR501 features a German-original imported LHI778 pyroelectric infrared probe with high sensitivity and strong reliability, delivering superior detection performance compared to similar products. Equipped with the BISS0001 dedicated signal processing chip for stable performance and a wide operating voltage range (2V-6V). Ultra-low power consumption with quiescent current below 50μA, specifically suited for battery-powered automatic control products, significantly extending battery life. Wide voltage input support from DC 4.5-20V offers strong compatibility for direct integration with various power systems. Two trigger modes (repeatable/non-repeatable) are flexibly selectable via jumper to suit different application scenarios. Both delay time and blocking time are independently adjustable for flexible configuration. The module reserves a position for photoresistor control, enabling optional daytime/bright light non-sensing functionality. Available in multiple specifications including standard, high sensitivity, and short delay versions. Sensing distance is easily adjustable via potentiometer (3-7 meters) to suit different installation environments. High-level 3.3V output directly interfaces with Arduino, Raspberry Pi, and other mainstream development boards without level shifting.
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FAQ
1. What is the HC-SR501 PIR Motion Sensor Module?
The HC-SR501 is a motion detection module based on Passive Infrared (PIR) technology. It detects changes in ambient infrared radiation caused by the movement of humans or warm-blooded animals and outputs a digital high/low level signal.
2. What are the key specifications of the HC-SR501 module?
Operating Voltage: 4.5V ~ 20V DC
Standby Current: < 50µA
Output Level: High 3.3V / Low 0V
Sensing Angle: < 100° cone angle (some sources specify < 120°)
Sensing Range: Up to 7 meters (adjustable)
Delay Time: 0.3s ~ 200s (adjustable)
Blocking Time: 2.5s (default)
Operating Temperature: -15°C ~ +70°C
Module Size: 32mm × 24mm
3. What package and interface does the HC-SR501 module use?
The module comes in PCB form, measuring 32mm × 24mm. It features 3 pins: VCC (power), GND (ground), and DOUT (signal output). A circular Fresnel lens (23mm diameter) is mounted on top.
4. What applications is the HC-SR501 module suitable for?
It is widely used in various automation sensing applications:
Burglar alarms and security systems
Automatic doors and smart lighting
Industrial automation and control
Smart home and IoT projects
Battery-powered automatic control products
5. What development tools support the HC-SR501 module?
The module can be used standalone without additional tools. When connecting to platforms like Arduino or Raspberry Pi, simply read the digital signal via GPIO. It supports direct programming in Arduino IDE and can also drive relays or LEDs independently.
6. What is the operating temperature range of the HC-SR501 module?
The operating temperature range is -15°C to +70°C. When ambient temperature approaches human body temperature (around 30-32°C), sensor sensitivity decreases significantly, and detection range may be reduced by approximately 15%.
7. What two trigger modes does the HC-SR501 module support?
The module supports two trigger modes, selectable via a jumper on the back:
Non-repeatable trigger (L mode) : After output goes high, it automatically returns to low when the delay ends; new activity during the delay does not reset the timer
Repeatable trigger (H mode, default) : After output goes high, it stays high as long as motion is detected during the delay period; the timer resets with each new detection
8. How do I adjust the delay time and sensing distance on the HC-SR501 module?
The module has two onboard potentiometers:
Delay adjustment potentiometer: Controls how long the output stays high, adjustable from 0.3s to over 200s
Sensitivity adjustment potentiometer: Turn clockwise to increase detection range (up to 7 meters), counterclockwise to decrease (down to 3 meters)
9. What should I consider when installing the HC-SR501 module?
Initialization time: The module requires about 60 seconds of calibration after power-on, during which 2-3 false triggers may occur — this is normal
Mounting orientation: The dual-element sensor should be parallel to the main direction of human movement; sideways motion is detected most sensitively
Avoid interference: Keep away from air conditioner vents, radiators, and other temperature-varying areas; avoid direct light on the lens; avoid direct airflow
Mounting height: Recommended 2 ~ 2.2 meters
10. How can I prevent false triggering when using the HC-SR501 module?
Power quality: Use a well-regulated and filtered power supply; avoid unregulated 9V batteries
Lens cleaning: Regularly clean the Fresnel lens surface to prevent dust and oil from causing infrared refraction anomalies
Temperature compensation: In high-temperature environments, an external NTC thermistor can be added to enable temperature compensation
Jumper setting: For crowded areas, use H (repeatable trigger) mode