The **WMS2-03-R/Q** is a specific variant of water flow sensor, typically utilized in appliances like coffee machines, water purifiers, and industrial liquid dispensing systems. It operates on the principle of the Hall Effect to measure the volume of liquid passing through it. --- ### 1. Technical Specifications The following table outlines the core electronic and mechanical parameters for this component: | Parameter | Specification | | :--- | :--- | | **Sensor Type** | Hall Effect Sensor | | **Operating Voltage (VCC)** | 3.5V to 18V DC | | **Output Type** | NPN Pulse Signal (Square Wave) | | **Flow Rate Range** | 0.3 to 6.0 Liters/min (Approx.) | | **Accuracy** | ±3% to ±5% | | **Max Current** | 10 mA - 15 mA | | **Insulation Resistance** | > 100MΩ | | **Operating Temperature** | ≤ 80°C | --- ### 2. Internal Electronic Components The device consists of three primary internal parts that work in unison to generate a signal: 1. **The Turbine (Impeller):** A mechanical rotor equipped with a permanent magnet. As water flows, it forces the turbine to spin. 2. **The Hall Effect IC:** A semiconductor sensor located outside the fluid chamber. It detects the magnetic field changes as the turbine magnets pass by. 3. **Circuit Board:** A small PCB that regulates the input voltage and provides an open-collector output (NPN), allowing for easy interfacing with microcontrollers like Arduino or ESP32. --- ### 3. Wiring Configuration The sensor typically features a 3-wire connection interface: | Wire Color | Function | Description | | :--- | :--- | :--- | | **Red** | VCC | Connect to Power Supply (e.g., +5V) | | **Black** | GND | Connect to Ground | | **Yellow** | Signal (OUT) | Pulse output (Requires a pull-up resistor) | --- ### 4. Interfacing Logic To read the data from the WMS2-03-R/Q, a microcontroller counts the number of pulses per second (frequency). The relationship between flow and frequency is generally expressed as: `Flow Rate (L/min) = Frequency (Hz) / K-factor` #### Example Code Snippet (Arduino) ```cpp const int sensorPin = 2; // Signal wire connected to digital pin 2 volatile int pulseCount = 0; void pulseCounter() { pulseCount++; } void setup() { pinMode(sensorPin, INPUT_PULLUP); attachInterrupt(digitalPinToInterrupt(sensorPin), pulseCounter, RISING); } ``` --- ### 5. Key Electronic Advantages * **Non-Contact Sensing:** The electronics are isolated from the water, preventing corrosion and short circuits. * **Digital Output:** Provides a clean square wave signal that does not require an Analog-to-Digital Converter (ADC). * **Low Power Consumption:** Ideal for battery-operated monitoring devices.