YF-S401 Water Flow Sensor

The YF-S401 Water Flow Sensor is a compact and efficient tool for accurately measuring liquid flow rates in real-time. This sensor operates on a simple principle: water flows through a turbine, and the rotation of the turbine generates a series of digital pulses. An embedded Hall Effect sensor detects these rotations, allowing you to easily calculate the volume of water passing through the unit. Engineers and hobbyists commonly choose the YF-S401 for its precision, small form factor, and ease of integration with microcontrollers like Arduino or Raspberry Pi. It offers a reliable and cost-effective way to monitor water consumption or manage liquid delivery in automated systems.

Key Features:

• Accurate Flow Measurement: It provides a digital pulse output, making flow rate calculation highly precise by counting the pulses per second.
• Hall Effect Sensor: This non-contact sensing method ensures durability and prevents wear-and-tear from the rotating turbine.
• Low Power Consumption: The sensor draws minimal current, making it suitable for battery-powered and continuous-monitoring projects.
• Compact Design: Its small size and lightweight construction allow for easy integration into tight spaces and portable systems.
• Simple Digital Output: You can directly connect the pulse signal to a digital input pin on a microcontroller, simplifying the required coding.
• Durable Construction: The body uses high-quality plastic, suitable for continuous contact with water.

Technical Specifications:

• Working Voltage Range: DC 5 V to 15 V (Optimal at 5V)
• Working Current: 15 mA (max)
• Flow Rate Range: Approximately 0.3 to 6 L/min
• Output Signal: Square Wave Pulse
• Pulse Frequency Formula: Frequency ($Hz$) = 98 $\times$ Flow Rate ($L/min$) (This value can vary slightly between units)
• Duty Cycle: 50% $\pm$ 10%
• Water Pressure Resistance: $\le$ 0.8 MPa

Mechanical Specifications:

• Connection Thread Size: G1/4″ male to male (compatible with 1/4 inch fittings)
• Material: Food-grade plastic (typically nylon or similar material)
• Tube Diameter: Internal diameter $\approx$ 6mm, Outer diameter $\approx$ 7.5mm
• Mounting: In-line installation. Ensure the flow direction matches the arrow on the sensor body.

Dimensions:

• Length: $\approx$ 58 mm (excluding connectors)
• Width: $\approx$ 35 mm
• Height: $\approx$ 28 mm

Pinout and Wiring:

• Red Wire (VCC): Connect to 5V power supply.
• Black Wire (GND): Connect to Ground.
• Yellow Wire (OUT): The Pulse Output signal. Connect this to a digital interrupt pin on your microcontroller (e.g., Digital Pin 2 or 3 on an Arduino Uno).
• Wiring Note: Always connect VCC to a stable 5V source and ensure all connections are watertight to prevent damage or leakage.

Datasheet Reference:

• Download Datasheet

Commonly Used in:

• Microcontroller Projects: Integrated into systems running on Arduino, ESP32, or Raspberry Pi to monitor small water volumes.
• Beverage Dispensers: Used for precise liquid dispensing in automated vending or brewing machines.
• Hydroponics/Aquaponics: Essential for monitoring nutrient solution flow to plants or water circulation in fish tanks.

Applications:

• Automatic Drip Irrigation: Accurately control the amount of water delivered to plants.
• Water Consumption Monitoring: Measure and log water usage in home or small-scale commercial settings.
• Cooling Systems: Monitor the circulation flow in PC liquid cooling loops or industrial equipment.
• Custom Coffee/Drink Machines: Ensure precise liquid measurement for recipes.

Equivalent Models:

• YF-S201: A larger flow sensor designed for higher flow rates (typically 1-30 L/min) with 1/2″ thread.
• FS300A/G3/4: A sensor for very high flow applications, commonly using 3/4″ pipe threads.

Package Includes:

• 1 x YF-S401 Water Flow Sensor