1/4 inch Water Flow Sensor YF-S402

1/4 inch Water Flow Sensor YF-S402 

The YF-S402 is a compact inline water flow sensor designed for use with small diameter pipes or tubing with a 1/4-inch connection size. It contains an internal turbine rotor that spins as water flows through the sensor body. A Hall-effect sensor inside detects each rotation of the turbine and generates a digital pulse output proportional to the flow rate. By counting these pulses with a microcontroller, controller board, or monitoring system, you can determine the flow rate and total volume of water passing through the line. Its small size and simple interface make it well-suited for DIY projects, automation systems, and microcontroller-based monitoring.

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Features

• Designed for 1/4-inch (G1/4) inline connection
• Built-in turbine and Hall-effect sensor
• Digital pulse output proportional to flow rate
• Simple 3-wire connection
• Lightweight and compact plastic body
• Low power consumption
• Easy to install inline with plumbing or tubing
• Works with microcontrollers (Arduino, ESP32, Raspberry Pi)
• Good for low-to-moderate flow measurement
• Reliable and low maintenance

Applications

• Small water monitoring systems
• Arduino/ESP32/Raspberry Pi DIY projects
• Mini pump control
• Aquarium water flow measurement
• Hydroponics and irrigation systems
• Home water automation systems
• Small dispenser and fluid tracking systems
• Education and prototype testing