Saier HZ21FC-B Water Flow Sensor (1–30 L/min) - 4.5-18V DC

The sensor provides both analog voltage and digital pulse output options. The digital output is a square wave pulse whose frequency is proportional to the flow rate. The analog output varies with flow, with a high-level voltage ≥4.5V and a low-level ≤0.5V, making it compatible with most microcontroller ADCs or digital input pins.

Yes. The operating voltage range of 4.5V to 18V DC includes the standard 5V logic from an Arduino. Ensure your power supply can provide the required ≤15mA current. For digital pulse reading, connect the signal wire to a digital input pin configured with a pull-up resistor or use the pulseIn() function.

The sensor is primarily designed for clean water and similar low-viscosity, non-corrosive liquids. Its brass construction offers good corrosion resistance for typical water applications. It is not recommended for use with aggressive chemicals, oils, or fluids containing large particulates that could damage the internal turbine mechanism.

Install the sensor inline with your water pipe, ensuring flow direction matches the arrow marked on the body. For calibration, you will need to establish a conversion factor between the output pulse frequency (or analog voltage) and a known flow rate. Use a calibrated container and timer to measure actual flow, then calculate pulses per liter for your specific setup.