Water Flow Sensor - Hall Effect Paddlewheel Flow Meter (Arduino/ESP32/RPi)
Key Specifications & Features
General Operation
Measures the flow rate of water by counting pulses from an internal Hall'effect sensor as the paddlewheel turns with liquid flow.
Outputs digital pulse signals easy to interface with microcontrollers like Arduino, ESP32, Raspberry Pi, PLCs, etc., by counting pulses per unit time.
Fluid & Environmental Specs
Fluid type: Clean water (suitable for potable water per drinking standards).
Temperature range: 080C (approx).
Housing material: Brass body (good corrosion resistance).
Max operating pressure: 1.75MPa (some listings show ~1.2MPa).
Electrical & Signal
Current draw: 15mA.
Output: Digital pulse (Yellow wire).
Connector: 3pin JST (Red = Vcc, Black = GND, Yellow = Pulse).
Pulse duty cycle: ~50%.
Flow Characteristics
Flow range: ~0.353.0L/min.
Flow to pulse relation: ~1L of water 1780 pulses.
Flow equation: F (Hz) = 73Q (L/min) ~10%. This means as flow increases, pulse frequency increases proportionally, letting your controller convert pulses to flow rate.
How It Works (Principle)
The sensor contains a small rotor with a magnet placed inside the brass body. As water flows through, the rotor spins. A
Typical Applications
Water purification & dispensers.
Coffee machines and vending systems.
Thermostatic water heaters.
Smart metering and embedded measurement systems.
Irrigation or small fluid flow monitoring systems.
Integration Tips
Installation
Install after a filter to avoid debris jamming the rotor.
Avoid areas with strong vibrations, which can affect pulse accuracy.
Reading the Sensor (with a Microcontroller)
Connect Yellow pulse pin to a digital interrupt pin.
Count pulses per time interval (e.g., per second) to compute flow rate. Example formula:
Flow (L/min)=Pulses in 1 sec601780\text{Flow (L/min)} = \frac{80}Flow (L/min)=1780Pulses in 1 sec60
Use debouncing or digital interrupts to improve counting accuracy if water turbulence causes noisy pulses.