SmartElex NS412 Digital PIR Motion Sensor Module

Overview

The SmartElex NS412 PIR Motion Sensor Module is a compact, low-power digital passive infrared (PIR) sensor used for human motion detection.

• Integrates:

  • Pyroelectric sensing element

  • Digital signal processing circuit

   

• Provides direct digital output (HIGH/LOW)

• Designed for low-power embedded and automation systems

Combines sensing + processing in a single module for stable detection

Working Principle

• Detects infrared radiation changes from human body movement

• Internal flow:

  • IR change analog signal

  • Amplification + filtering

  • Digital conversion (threshold detection)

   

• When motion exceeds threshold:

  • REL output is triggered (digital HIGH)

   

All signae chip

Internal Architecture

• Pyroelectric IR sensing element

• High-impedance differential amplifier

• Digital processing IC

• Band-pass filter (removes noise)

• Threshold detection logic

Includes electromagnetic shielding for stability

Electrical Characteristics

• Operating Voltage: 2.2V 3.7V

• Static Current Consumption: < 11 A

Ultra-low power suitable for battery-powered devices

Detection Characteristics

• Detection Range: up to 10 meters

• Detection Angle: ~120 (horizontal)

• Sensing Window Size: ~3 4 mm

Performance depends on Fresnel lens used

Output Characteristics

• Output ul>

• HIGH Motion detected

• LOW No motion

Directly compatible with microcontrollers

Functional Features

• Integrated digital PIR processing

• Adjustable delay time via external resistor

• Built-in:

  • Noise filtering

  • RF interference suppression

  • Stable threshold detection

Performance Characteristics

• High noise immunity

• Low false triggering

• Short warm-up time

• Stable operation in noisy environments

Functional Behavior

• Detects only motion (dynamic IR changes)

• Best detection when movement is:

  • Across sensor field (side motion)

• Outputs:

  • Digital pulse with configurable delay

Key Technical Fe11 A)

Digital output (no external amplifier needed) Wide detection angle (120) Long sensing range (~10 m) Adjustable delay timing Integrated signal processing Compact module design

Advantages

• Very low power consumption

• Simple digital interface

• Stable and reliable detection

• Compact and lightweight

• Easy integration into embedded systems

Limitations

• Cannot detect stationary objects

• Performance affected by:

  • Temperature changes

  • External heat sources

• Requires proper lens and placement

• Limited configuration compared to advanced PIR ICs

Technical Summary

The NS412 module is a low-power digital PIR motion sensor that:

• Integrates IR sensing + signal processing

• Provides direct digitli>Is optimized for compact, battery-powered, and IoT applications

Compared to higher-end PIR sensors:

• Simpler but very power-efficient

• Good balance of range, stability, and ease of use</