The HC-SR505 Mini Infrared Motion Detector is a compact, low-power human body sensing module designed for automatic lighting, security systems, and smart home automation. It uses pyroelectric infrared (PIR) technology to detect motion and automatically switch connected devices on or off, making it an ideal solution for energy-saving applications, occupancy detection, and DIY electronics projects.
At the heart of the module is a pyroelectric infrared sensor that detects changes in infrared radiation caused by moving human bodies. When motion is detected within the sensor’s field of view (typically 100° cone angle), the module outputs a HIGH signal on the OUT pin. The signal remains HIGH for a fixed delay time (approximately 8 seconds), after which it automatically returns to LOW if no further motion is detected.
The module operates from 4.5V to 20V DC, making it compatible with a wide range of power sources including 5V and 12V systems. The ultra-low power consumption makes it suitable for battery-powered and energy-conscious applications. The module features a compact form factor measuring approximately 10mm × 23mm, significantly smaller than the standard HC-SR501, making it ideal for space-constrained designs.
The HC-SR505 is designed for automatic ON/OFF control — when motion is detected, the output goes HIGH and can trigger a relay, microcontroller interrupt, or other control circuit. When motion ceases and the delay time expires, the output returns to LOW. This makes it ideal for automatic lighting, security alarms, occupancy detection, and smart home automation.
The module features a 3-pin interface (VCC, GND, OUT) for easy connection to microcontrollers. The fixed delay time of approximately 8 seconds simplifies integration, while the high sensitivity ensures reliable detection of human movement. The module is widely used in automatic lighting, security systems, smart home devices, occupancy sensors, battery-powered alarms, and DIY electronics projects.
Important Note: The HC-SR505 has a fixed delay time (approximately 8 seconds) and fixed sensitivity. For applications requiring adjustable delay and sensitivity, consider the HC-SR501. Avoid mounting the module where it faces direct sunlight or near heat sources, as these can cause false triggering. Allow 30–60 seconds for the module to stabilize after power-up.
Whether you are building an automatic lighting system, a security alarm, or a smart home device, the HC-SR505 Mini Infrared Motion Detector provides a reliable, compact solution. It is suitable for individual makers, students, and businesses purchasing in bulk for product development or educational programs.
Features
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Pyroelectric infrared (PIR) sensor — Reliable human body detection
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Auto ON/OFF control — Output goes HIGH on motion, returns LOW after delay
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Ultra-compact form factor — Approximately 10mm × 23mm
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Wide operating voltage — 4.5V to 20V DC
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Low power consumption — Suitable for battery-powered applications
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Digital output — HIGH signal on motion detection
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100° detection angle — Wide field of view
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Fixed delay time — Approximately 8 seconds
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3-pin interface — VCC, GND, OUT for easy connection
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Wide application range — Automatic lighting, security, smart home, occupancy detection
Technical Specifications
| # | Parameter | Specification |
|---|---|---|
| 1 | Module Model | HC-SR505 |
| 2 | Sensor Type | Pyroelectric infrared (PIR) |
| 3 | Operating Voltage | 4.5V – 20V DC |
| 4 | Standby Current | < 50µA |
| 5 | Detection Angle | 100° (typical) |
| 6 | Detection Range | Up to 3 meters |
| 7 | Output Signal | Digital HIGH on motion detection |
| 8 | Delay Time | Approx. 8 seconds (fixed) |
