A microwave sensor emits electromagnetic waves in the microwave frequency range and detects changes in the reflected waves. When an object moves within the sensor’s range, the emitted waves hit the object and bounce back to the sensor. This creates a shift in frequency due to the Doppler effect, which the sensor identifies as movement. The sensor then triggers a response, such as turning on a light or activating an alarm. Unlike infrared or ultrasonic sensors, microwave sensors can detect movement through walls, glass, or other non-metallic objects, making them highly effective for security systems, automatic doors, and industrial applications. They are also more reliable in challenging environments, as they are less affected by temperature, light, or environmental conditions.