1/8 Inch Water Flow Sensor YF-S401
📌 Overview
The YF-S401 Water Flow Sensor is a compact sensor used to measure water flow rate in small pipes.
👉 Ideal for:
🚰 Water dispensing systems
🌱 Irrigation systems
🤖 Arduino & IoT projects
☕ Coffee machines & appliances
🧠 Working Principle
Inside → rotating turbine (rotor) + Hall Effect sensor
Water flows → rotor spins
Speed of rotation ∝ flow rate
Sensor outputs pulse signals
👉 Based on Hall Effect
✔ More flow → more pulses
📊 Infographic Summary
┌──────────────────────────────┐
│ 💧 YF-S401 FLOW SENSOR │
├──────────────────────────────┤
│ 🎯 Measures: Water flow │
│ 📏 Range: 0.3–6 L/min │
│ ⚡ Voltage: 5V–24V │
│ 🔌 Output: Pulse signal │
│ 📦 Size: 1/8 inch │
│ 🧠 Tech: Hall Effect │
└──────────────────────────────┘
🔌 Pin Configuration
┌────────────────────┐
│ YF-S401 Sensor │
├────────────────────┤
│ Red → VCC (5–24V)
│ Black → GND
│ Yellow→ Signal
└────────────────────┘
⚙️ Key Specifications
⚡ Operating Voltage: 5V – 24V DC
📏 Flow Range: 0.3 – 6 L/min
🔌 Output: Digital pulse signal
🎯 Accuracy: ±5%
🔋 Current Consumption: ~15 mA
🌡 Max Liquid Temp: up to 120°C
💧 Pressure: up to ~0.8–2 MPa
🔄 Pulse Output Formula
👉 Typical relation:
1 Liter ≈ 5880 pulses
So,
Flow rate = pulses per second ÷ calibration factor
🌟 Key Features
💧 Compact 1/8" pipe size
⚡ Low power consumption
🔧 Easy to interface
📊 Pulse output (easy to count)
📦 Waterproof internal design
🧪 Applications
🚰 Water flow monitoring
🌱 Smart irrigation systems
☕ Coffee/tea machines
🧪 Liquid dispensing systems
🤖 IoT water management
🏭 Cooling systems (CNC/laser)
🔗 Interfacing
Compatible with:
🔵 Arduino
📡 ESP32 / ESP8266
🍓 Raspberry Pi
👉 Connect signal → digital pin (interrupt recommended)
🔄 Working Example
👉 Water Monitoring System:
Water flows through sensor
Rotor spins
Pulses generated
Microcontroller counts pulses
Displays flow rate or total volume
⚠️ Important Notes
⚠️ Must be installed vertically for accuracy
⚠️ Avoid air bubbles (affects readings)
⚠️ Not suitable for dirty/corrosive liquids
⚠️ Needs calibration for precise measurement
🆚 YF-S401 vs YF-S201
| Feature | YF-S401 | YF-S201 |
|---|---|---|
| Pipe Size | 1/8 inch | 1/2 inch |
| Flow Range | 0.3–6 L/min | 1–30 L/min |
| Use Case | Small systems | Medium systems |
💡 Pro Tip
Use interrupt pin for accurate pulse counting
Add filter or debounce logic in code
👉 Perfect for low-flow precision measurement projects
