HC-SR505 Mini PIR (Passive Infrared) Motion Sensor

🔥 HC-SR505 Mini PIR Motion Sensor
🧩 What is it?
The HC-SR505 is a mini Passive Infrared (PIR) sensor used to detect human or animal motion by sensing infrared (heat) radiation. It outputs a digital signal when motion is detected.
📊 Key Features (Infographic Points)
🔹 Core Features
👁️ Detects infrared radiation from living beings
⚡ Ultra-low power consumption (ideal for battery projects)
📏 Compact size (perfect for small devices)
🔁 Repeatable trigger mode (default)
🔹 Technical Specifications
🔌 Operating Voltage: 4.5V – 20V DC
📡 Detection Range: ~3 meters
🔄 Detection Angle: ~100° cone
⚡ Output: HIGH (3.3V) / LOW (0V)
⏱️ Delay Time: ~8 seconds (adjustable in some variants)
🔋 Current Consumption: < 60 µA (very low)
🌡️ Working Temp: -20°C to +80°C
⚙️ How It Works
🔥 Detects changes in infrared heat radiation
🚶 When a person enters range → Output goes HIGH
⏳ After motion stops → Output returns LOW after delay
🔁 If motion continues → delay resets automatically
🔌 Pin Configuration
VCC → Power (5V–12V typical)
OUT → Digital output signal
GND → Ground
💡 Advantages
🔋 Excellent for battery-powered devices
📦 Very small size (≈ 10 × 23 mm)
🧠 Easy interface with:
Arduino
ESP32
Raspberry Pi
⚠️ Limitations
❌ Shorter range than larger PIR sensors (like HC-SR501)
⚠️ Sensitive to electrical noise in some setups (needs stable power)
🔧 Limited adjustability (fewer controls than bigger modules)
🏠 Common Applications
💡 Automatic lights (motion-based)
🚪 Security & intrusion detection
🤖 Robotics motion sensing
🧸 Smart toys / IoT devices
📦 Battery-powered automation systems
🧠 Pro Tips
Keep sensor away from heat sources (fans, sunlight)
Use stable power supply to avoid false triggers
Mount at human height (~1–2m) for best detection