Saier HZ43WB Water Flow Sensor (2–45 L/min, 4.5–18V DC)

The HZ43WB provides both a digital pulse output and an analog voltage output. The digital output is a square wave signal where the frequency is proportional to the flow rate. The analog output voltage varies linearly with the flow rate across the specified 2–45 L/min range, making it compatible with both digital and analog microcontroller inputs.

The sensor operates on a wide DC voltage range of 4.5 to 18V, making it compatible with 5V and 12V systems. It has three wires: Red (VCC), Black (GND), and Yellow (Signal Output). The signal wire carries the pulsed output. Ensure the supply current capacity is at least 15mA. Always use a regulated power supply for stable sensor readings.

While primarily designed and calibrated for water and similar low-viscosity liquids, the turbine mechanism can respond to gas flow. However, accuracy is not guaranteed for gases, as the calibration and rotor dynamics are optimized for liquid density and viscosity. For precise gas flow measurement, a sensor specifically designed and calibrated for gaseous media is recommended.

For the digital pulse output, connect the signal wire to a digital interrupt pin on the Arduino. Use the pulse frequency to calculate the flow rate. For the analog output, connect it to an analog input pin (ADC). On Raspberry Pi, an external ADC is required for the analog signal. Sample code for calculating flow rate from frequency is typically provided by the manufacturer or available in open-source libraries.