HC-SR505 Mini Infrared PIR Motion Sensor Infrared Detector Module

HC-SR505 Mini Infrared PIR Motion Sensor Infrared Detector Module
Despite its size, the HC-SR505 features a fully integrated Fresnel lens that focuses infrared radiation onto a high-sensitivity pyroelectric element. It operates on a "set-and-forget" principle, with its sensitivity and delay time pre-calibrated for general-purpose use.

 
Why it’s a Portable & IoT Essential:
• Space-Saving Design: At roughly the size of a finger-tip, it can be hidden inside 3D-printed cases, small lamps, or picture frames without being intrusive.
• Ultra-Low Power: It is specifically engineered for low-power standby. This makes it perfect for battery-powered IoT nodes that need to last for months on a single charge.
• Wide Voltage Range: Like the larger version, it accepts anywhere from 4.5V to 20V, but outputs a clean 3.3V digital HIGH signal. This makes it natively compatible with both 5V Arduinos and 3.3V chips like the ESP32.
• Simplicity: With no potentiometers to adjust, it provides a consistent, factory-calibrated experience that is less prone to "drift" caused by vibration.

 
Technical Capabilities:
• Detection Range: Approximately 3 to 5 meters, providing a smaller but more focused detection "bubble."
• Fixed Delay: Once motion stops, the output stays HIGH for approximately 8 seconds before resetting.
• Digital Logic: Outputs a simple HIGH (3.3V) when motion is detected and LOW (0V) when the area is clear.

 
Best For:
The HC-SR505 is the primary choice for closet/cabinet lighting, portable security gadgets, battery-operated welcome mats, and miniature robotics.