YF-B8 1/2″ Brass Water Flow Sensor Hall Effect Pulse Flowmeter 5–18V Arduino

#include <Arduino.h>

const byte flowSensorPin = 2; // Must be interrupt-capable on UNO (2 or 3)
volatile unsigned long pulseCount; // Incremented in ISR

// Calibration factor for this sensor:
// Frequency (Hz) = 11 * Q(L/min)
const float calibrationFactor = 11.0;

unsigned long oldTime = 0;
float flowLMin = 0.0;
float totalLitres = 0.0;

void IRAM_ATTR flowPulseISR() {
pulseCount++;
}

void setup() {
Serial.begin(9600);
delay(1000);

pinMode(flowSensorPin, INPUT_PULLUP); // enable internal pull-up
pulseCount = 0;

attachInterrupt(digitalPinToInterrupt(flowSensorPin), flowPulseISR, FALLING);

Serial.println("YF-B8 Water Flow Sensor Test");
Serial.println("Open Serial Monitor at 9600 baud.");
}

void loop() {
unsigned long currentTime = millis();

// Calculate every 1 second
if (currentTime - oldTime >= 1000) {
detachInterrupt(digitalPinToInterrupt(flowSensorPin));

unsigned long pulses = pulseCount;
pulseCount = 0;
oldTime = currentTime;

// pulses per second = frequency (Hz)
float frequency = (float)pulses; // since interval is 1 second
flowLMin = frequency / calibrationFactor; // L/min

// Convert L/min to litres over 1 second
float litresThisInterval = (flowLMin / 60.0);
totalLitres += litresThisInterval;

Serial.print("Flow: ");
Serial.print(flowLMin, 2);
Serial.print(" L/min\tTotal: ");
Serial.print(totalLitres, 3);
Serial.println(" L");

unsigned long oldTime = 0;
float flowLMin = 0.0;
float totalLitres = 0.0;

void IRAM_ATTR flowISR() {
pulseCount++;
}

void setup() {
Serial.begin(115200);
delay(1000);

pinMode(flowPin, INPUT_PULLUP); // use 3.3V pull-up

attachInterrupt(digitalPinToInterrupt(flowPin), flowISR, FALLING);
Serial.println("ESP32 YF-B8 Flow Sensor Test");
}

void loop() {
unsigned long now = millis();
if (now - oldTime >= 1000) {
detachInterrupt(digitalPinToInterrupt(flowPin));

unsigned long pulses = pulseCount;
pulseCount = 0;
oldTime = now;

float frequency = (float)pulses;
flowLMin = frequency / calibrationFactor;
float litresThisInterval = flowLMin / 60.0;
totalLitres += litresThisInterval;

Serial.print("Flow: ");
Serial.print(flowLMin, 2);
Serial.print(" L/min\tTotal: ");
Serial.print(totalLitres, 3);
Serial.println(" L");