HC-SR501 Adjustable PIR Motion Detector Module 🔔

The HC-SR501 Adjustable PIR Motion Detector is a compact, easy-to-use motion sensor module designed for detecting human or animal movement using PIR (Passive Infrared) technology. Ideal for security systems, automatic lighting, and occupancy detection, it integrates seamlessly with popular microcontroller platforms such as Arduino, Raspberry Pi, ESP32, and other DIY electronics projects.

How It Works 🔍

When no motion is present, the sensor’s digital output remains at logic 0. Upon detecting movement, the output switches to logic 1 (active HIGH). The board includes two adjustable trimpots:

• Sx (Sensitivity): Adjusts the detection range between 3–5 meters.
• Tx (Time): Sets the hold time for how long the output stays HIGH after motion, adjustable from 5–200 seconds.

Key Features ✅

• Wide supply voltage: DC 5 V to 20 V for flexible power options.
• Digital output levels: HIGH ≈ 3.3 V, LOW = 0 V.
• Embargo (lockout) time: 0.2 seconds between triggers.
• Detection range: Adjustable 3–5 meters.
• Detection angle: Approximately 140° field of view.
• Hold time: Adjustable 5–200 seconds after motion is detected.
• Operating temperature: -15°C to +70°C for indoor and sheltered outdoor use.
• Easy integration with Arduino, Raspberry Pi, and other microcontroller platforms.

Integration & Pinout 🤝

This module is well-suited for electronics components prototyping and embedded systems. Typical 3-pin interface:

• VCC: DC 5–20 V input
• OUT: Digital signal output (HIGH ≈ 3.3 V when motion detected)
• GND: Ground

Note: The 3.3 V logic HIGH is compatible with most 5 V-tolerant inputs on Arduino. For systems requiring 5 V logic levels, consider a level shifter.

Typical Applications 💡

• Security: Burglar alarms and intrusion detection
• Automation: Motion-activated lighting and energy-saving controls
• IoT/DIY: Smart home projects with Arduino, Raspberry Pi, ESP32, and other modules

Specifications 📊

• Working voltage: DC 5 V to 20 V
• Logic signal voltage: HIGH ≈ 3.3 V, LOW = 0 V
• Embargo time: 0.2 s
• Working temperature: -15°C to +70°C
• Detection range: 3–5 m (adjustable via Sx)
• Detection angle: 140°
• Hold time: 5–200 s (adjustable via Tx)

Dimensions 📏

PCB size: 32 × 24 mm. Mounting hole spacing: 28 mm. Mounting hole diameter: 2 mm. Fresnel (induction) lens diameter: 23 mm (default).