FS300A Water Flow Sensor - Hall Effect Pulse Output, 1-60 L/min

The FS300A outputs a digital pulse signal. Each pulse corresponds to a specific volume of fluid. You connect the sensor's signal wire to a digital input pin on a microcontroller (like an Arduino) and use an interrupt or polling routine to count pulses over time to calculate the flow rate. The sensor requires a pull-up resistor on the signal line, typically included in the module or provided externally.

The sensor is rated for a maximum water pressure of 1.75 MPa (approximately 254 PSI) and an operating fluid temperature range of 0 to 80 degrees Celsius. Exceeding these limits may cause mechanical failure or inaccurate readings. For hot water applications, ensure the temperature stays within this specified range.

Calibration involves determining the K-factor (pulses per liter). Run a known volume of water through the sensor (e.g., 1 liter) and count the number of output pulses. The K-factor is calculated as (Pulse Count / Known Volume). This factor is then used in your code to convert future pulse counts into volumetric flow rate. For best accuracy, perform calibration near your typical operating flow rate.

While designed for water, it may work with other clean, non-corrosive, non-abrasive liquids of similar viscosity. However, performance and longevity are not guaranteed. Avoid using it with chemicals that may degrade the plastic body or seals, or with liquids containing particulates that could jam the rotor. Always install an inline filter if fluid purity is uncertain.