PIR & Motion Sensor
PIR & Motion Sensor
Introduction Many modern microcontrollers like ESP32, Raspberry Pi Pico, and STM32 use 3.3V logic. Traditional PIR sensors like HC-SR501 are designed for 5V. Connecting them directly can cause problems. The Problems 1. Power Supply Voltage HC-SR501 requires at least 4.5V…
Introduction Insects and spiders are a surprisingly common cause of PIR sensor false triggers. A crawling insect near the lens can look like a warm moving object to the sensor. How Insects Cause False Triggers Direct Contact An insect crawling…
Introduction Outdoor PIR sensors often false-trigger during rain or snow. This is a common complaint, especially with inexpensive sensors. Understanding why helps in finding solutions. Why Rain and Snow Cause False Triggers Water Droplets on Lens Water absorbs infrared strongly.…
Introduction Just as cold weather affects PIR sensors, high temperatures can also cause problems. When ambient temperature approaches human body temperature (37°C), the contrast between a person and the background disappears, making detection difficult or impossible. Why High Temperature Causes…
Introduction Staircases are high-risk areas for falls, especially in the dark. PIR sensors can trigger lighting when someone approaches, improving safety and saving energy. Applications Automatic Stair Lighting Lights turn on when person approaches staircase, turn off after they pass.…
Introduction Greenhouses are controlled environments where automation can improve efficiency. PIR sensors contribute by detecting pests, tracking workers, and automating responses. Applications in Greenhouses Pest Detection Detect larger animal pests like rodents, rabbits, or birds that enter the greenhouse. Trigger…
Introduction Smart classrooms use technology to enhance learning and save energy. PIR sensors contribute to both goals through occupancy detection and activity monitoring. Applications in Classrooms Occupancy-Based Lighting and HVAC Lights and HVAC automatically turn off when classroom is empty,…
Introduction Smart elevators use sensors to optimize operation. PIR sensors can detect if people are waiting or inside, enabling more efficient dispatching. Applications in Elevators Waiting Area Detection Detect people waiting for elevator on each floor. If no one is…
Introduction Smart waste management systems need to know when bins are used and how full they are. PIR sensors can detect people approaching bins, indicating usage. Applications in Waste Management Usage Detection Detect when someone approaches a bin to deposit…
Introduction With aging populations, technology for elderly care is increasingly important. PIR sensors offer a privacy-preserving way to monitor activity and detect falls. Applications in Elderly Care Fall Detection A fall has a characteristic signature: rapid movement followed by prolonged…