Introduction While commonly used for motion detection, pyroelectric sensors are also the heart of Non-Dispersive Infrared (NDIR) gas sensors. This article explains the principles and applications. NDIR Principle NDIR gas sensing works on the principle that many gases absorb infrared…

Introduction The optical window of a PIR sensor protects the pyroelectric element while allowing infrared radiation to pass. Two common materials are silicon and germanium. This article compares their properties. Silicon Windows Silicon (Si) is the most common window material…

Introduction Noise Equivalent Power (NEP) is a key figure of merit for infrared detectors. It quantifies the minimum detectable signal power. This article explains what NEP means for PIR sensors and how to use it in design. Definition of NEP…

Introduction Thermal camera arrays (e.g., MLX90640, AMG8833) are becoming popular for occupancy sensing. This article compares them with traditional PIR sensors to help you choose the right technology. How Thermal Camera Arrays Work Thermopile arrays consist of multiple thermopile sensors…

Introduction The final stage in a PIR signal chain is a comparator that converts the analog signal to a clean digital output. Adding hysteresis prevents oscillation when the signal hovers near the threshold. Why Hysteresis is Essential Without hysteresis, when…

Introduction The raw output from a pyroelectric sensor is a tiny signal, typically millivolts or less, requiring significant amplification before it can be processed. This guide covers the design of a complete analog front-end. Signal Characteristics Amplitude: 1-50 mV peak-to-peak…

Introduction To properly place a PIR sensor, you need to understand its field of view (FOV) and how it translates to actual coverage area. This article provides the formulas and calculations needed. Basic Parameters Horizontal FOV (θ_h): The angle the…

Introduction The Murata IRA-S200ST01 is a high-performance pyroelectric infrared sensor widely used in security systems, automatic doors, and occupancy detection. This article provides a complete technical analysis of its specifications, characteristics, and integration requirements. Key Specifications Parameter Value Package TO-5…