6.1K views · 15 reactions | How do motion sensor lights work? Those outdoor lamps that switch on when you walk by use passive infrared sensors. They detect tiny changes in infrared radiation when a warm body moves across their field of view. The sensor triggers a circuit that powers the light instantly. Engineers design them to ignore small fluctuations like wind or rain, so they only react to significant movement. A simple, brilliant mix of electronics and safety. | Electricalgram | Facebook