YF-S402 Water Flow Sensor 1/4 Inch

The YF-S402 Water Flow Sensor uses that mechanism in a compact 1/4 inch body measuring flow from 1 to 5 litres per minute. A water flow sensor works by placing a small turbine wheel inside the water pipe. As water flows past the turbine, it spins. A hall effect sensor inside the body detects each rotation and sends a pulse to the microcontroller — the faster the water flows, the more pulses arrive per second. Counting those pulses and applying the sensor’s calibration factor converts pulse frequency directly into flow rate in litres per minute.

The water flow sensor YF-S402 operates from 4.5V DC at 15mA maximum, making it compatible with both 5V Arduino and 3.3V ESP32 systems with a simple pull-up resistor on the signal line. The 1/4 inch outer diameter pipe gauge fits the standard tubing used in coffee machines, water purifiers, and drip irrigation systems — the same thread size as most RO membrane housings and small pump fittings. Liquid temperature tolerance reaches 120°C, which covers hot water dispensing applications alongside cold water measurement.

Water pressure limit is 0.35 MPa — adequate for domestic water supply pressure but not high-pressure industrial line use. The 1/4 inch water flow sensor suits water dispenser volume tracking, drip irrigation monitoring, and aquarium circulation flow measurement. Available on StemVolt. This Water Flow Sensor for working on water flow measurement and practical fluid monitoring projects.

Related Products:

• Checkout Water Flow Sensor YF-S401

Features:

• Hall effect pulse output counts turbine rotations for flow rate calculation
• 1 to 5 L/min measurement range suits low-flow domestic water system builds
• 4.5V DC at 15mA supply draws minimal current from battery-powered sensor nodes
• Liquid temperature tolerance covers hot water dispensing application builds
• A pressure rating suits domestic supply pressure water line integration

Technical Specifications:

 Applications:

• YF-S402 Water Flow Sensor tracks water volume dispensed in Arduino
• Monitors drip irrigation flow rate in automated garden watering system
• Water flow sensor measure aquarium circulation pump flow rate in tank monitoring
•  Tracks hot water consumption in solar water heater monitoring
• 1/4 inch water flow sensor YF-S402 measures RO purifier output flow in water quality monitor

Package Include:

• 1 x YF-S402 Water Flow Sensor 1/4 Inch