A rainfall sensor is a device designed to detect and measure the presence, intensity, or amount of rainfall in an environment. It monitors precipitation events and converts the collected information into electrical or digital signals, which can be recorded, analyzed, or used to trigger automated responses such as irrigation control or weather monitoring alerts.

Rainfall sensors operate using different measurement principles depending on the application. Common types include tipping bucket sensors, which measure accumulated rainfall by counting bucket tips; optical or capacitive sensors, which detect the presence and intensity of rain; and acoustic or piezoelectric sensors, which sense the impact of raindrops.

Modern rainfall sensors are durable, weather-resistant, and capable of accurate outdoor operation over long periods. Many models also support real-time data transmission and integration with IoT platforms, smart irrigation systems, and environmental monitoring networks.

Rainfall sensors are widely used in agriculture, smart farming, urban water management, environmental research, and automated irrigation systems, helping optimize water usage, protect crops, and support data-driven decision-making based on accurate precipitation measurements.