3/4 Inch Water Flow Sensor SEN-HZ43WA

📏 3/4″ Water Flow Sensor — SEN‑HZ43WA
A water flow sensor like the SEN‑HZ43WA measures the rate and volume of water flow through a pipe using a simple mechanical and electronic sensing method.
📌 Core Concept — How It Works
Water In → [Rotor / Paddlewheel] → Spins
↓
Magnet Attached to Rotor
↓
Hall Effect Sensor Detects
↓
Electrical Pulses Sent to MCU
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Flow Rate & Volume Calculated by Pulse Count
✔ Water pushes a turbine/paddle wheel inside the sensor.
✔ A magnet on the wheel triggers pulses via a Hall effect sensor as it spins.
✔ Each pulse correlates to a small volume of water passing through.
✔ By counting pulses over time, you get flow rate and total volume.
📊 Specifications & Operating Parameters
+----------------------------------------------------+
| Model: SEN-HZ43WA |
+----------------------------------------------------+
| Effective Pipe Size | 3/4″ (G3/4 thread) |
| Sensor Type | Hall Effect Flow Sensor |
| Material | Plastic (Body) |
| Flow Range | 2 – 45 L/min |
| Voltage Range | DC 3V – 12V (typ. DC5V) |
| Operating Current | ~15 mA |
| Max Water Pressure | ≤ 1.75 MPa |
| Operating Temp | -25°C to 80°C |
| Pulse Output | Digital pulse signal |
| Conversion Rate | ~477 pulses per liter |
| Connector Wires | 3 (Red/Black/Yellow) |
| Size (L×W×H) | ~60×37×37 mm |
| Weight | ~43 g |
+----------------------------------------------------+
Values are typical and may vary with manufacturer tolerances. 
🧱 Pin / Wire Function
Red → Power Input (DC 3–12V)
Black → Ground
Yellow→ Pulse Output
✔ The yellow wire pulses at a frequency proportional to flow rate.
✔ Measuring pulse frequency → you calculate L/min.
⚙️ Electrical & Mechanical Notes
Hall Effect Output: Sensor output is digital — each rotation of the wheel produces one pulse.
G3/4 Thread: Standard threaded connection for 3/4″ plumbing fittings.
Low Power: Works with typical small microcontrollers (Arduino, ESP32, Raspberry Pi) which read pulse signals.
📈 Typical Working Principle
Flow (L/min) ∝ Pulse Frequency (Hz)

Q = F × K

Where:
Q = Flow rate (L/min)
F = Pulse frequency (Hz)
K = Conversion factor (~0.133 L per Hz)
(Example: If F = 10 Hz → Q ≈ 1.33 L/min)
Pulse calibration varies; check datasheet or measure experimentally.
🛠️ Application Areas
✔ Irrigation systems & water dispensers
✔ Water heaters & circulation systems
✔ DIY flow measurement projects
✔ Cooling systems & industrial automation
✔ Water treatment & monitoring systems
✔ Embedded systems needing real‑time flow data
⚠️ Installation & Practical Considerations
✅ Orientation: Install the sensor in line with the pipe; match flow direction.
✅ Filtering: Install a screen filter upstream to prevent debris jamming the rotor.
✅ Straight Pipe: Best performance when installed with some straight pipe length before/after.
✅ Avoid Air Bubbles: Excessive air reduces accuracy.
✅ Voltage Levels: Match your MCU voltage; ideal voltage is around 5 V for logic compatibility.
✔ Summary — What This Sensor Gives You
Digital pulse output for water flow measurement.
Easy integration with microcontrollers.
Works in many DIY/industrial water systems.
Provides both flow rate and total volume data.