code reset volume and pulseCounts 0 of five yfs 401 in esp32 with connect php mysql database by ArduinoJson
This solution involves an ESP32 reading five YF-S401 flow sensors and sending the data to a MySQL database via a PHP script. After a successful database update, the ESP32 resets the pulseCounts and volume to zero. 
1. ESP32 Arduino Code
This code uses ArduinoJson to package data and HTTPClient to send it. 
cpp
#include <WiFi.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>

// WiFi and Server Config
const char* ssid = "YOUR_SSID";
const char* password = "YOUR_PASSWORD";
const char* serverUrl = "http://your-domain.com";

// Sensor Configuration
const int numSensors = 5;
const int flowPins[numSensors] = {4, 5, 18, 19, 21}; // ESP32 GPIOs
volatile long pulseCounts[numSensors] = {0, 0, 0, 0, 0};
float volumes[numSensors] = {0, 0, 0, 0, 0};
const float calibrationFactor = 5880.0; // Pulses per Liter for YF-S401

// Interrupt functions for each sensor
void IRAM_ATTR pulseCounter0() { pulseCounts[0]++; }
void IRAM_ATTR pulseCounter1() { pulseCounts[1]++; }
void IRAM_ATTR pulseCounter2() { pulseCounts[2]++; }
void IRAM_ATTR pulseCounter3() { pulseCounts[3]++; }
void IRAM_ATTR pulseCounter4() { pulseCounts[4]++; }

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) delay(500);

  void (*interrupts[])() = {pulseCounter0, pulseCounter1, pulseCounter2, pulseCounter3, pulseCounter4};
  for (int i = 0; i < numSensors; i++) {
    pinMode(flowPins[i], INPUT_PULLUP);
    attachInterrupt(digitalPinToInterrupt(flowPins[i]), interrupts[i], FALLING);
  }
}

void loop() {
  static unsigned long lastSend = 0;
  if (millis() - lastSend > 10000) { // Send every 10 seconds
    sendData();
    lastSend = millis();
  }
}

void sendData() {
  if (WiFi.status() == WL_CONNECTED) {
    StaticJsonDocument<300> doc;
    JsonArray data = doc.createNestedArray("sensors");

    for (int i = 0; i < numSensors; i++) {
      volumes[i] = (float)pulseCounts[i] / calibrationFactor; // Calculate Volume
      JsonObject obj = data.createNestedObject();
      obj["id"] = i + 1;
      obj["pulses"] = pulseCounts[i];
      obj["volume"] = volumes[i];
    }

    String jsonString;
    serializeJson(doc, jsonString);

    HTTPClient http;
    http.begin(serverUrl);
    http.addHeader("Content-Type", "application/json");
    
    int httpResponseCode = http.POST(jsonString);
    if (httpResponseCode > 0) {
      Serial.println("Data sent successfully. Resetting counters...");
      // RESET: Set all counts and volumes back to 0 after success
      for (int i = 0; i < numSensors; i++) {
        pulseCounts[i] = 0;
        volumes[i] = 0.0;
      }
    }
    http.end();
  }
}
Use code with caution.

2. PHP Script (update_flow.php)
This script receives the JSON and updates your MySQL database. 
php
<?php
$servername = "localhost";
$username = "db_user";
$password = "db_password";
$dbname = "flow_db";

$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) die("Connection failed: " . $conn->connect_error);

$json = file_get_contents('php://input');
$data = json_decode($json, true);

if (!empty($data['sensors'])) {
    foreach ($data['sensors'] as $sensor) {
        $id = $sensor['id'];
        $pulses = $sensor['pulses'];
        $volume = $sensor['volume'];
        
        // Update total or log reading
        $sql = "UPDATE flow_readings SET last_pulses=$pulses, total_volume=total_volume+$volume WHERE sensor_id=$id";
        $conn->query($sql);
    }
    echo "Success";
}
$conn->close();
?>
Use code with caution.

3. Database Schema
Create a table to store the sensor data: 
sql
CREATE TABLE flow_readings (
    sensor_id INT PRIMARY KEY,
    last_pulses INT DEFAULT 0,
    total_volume FLOAT DEFAULT 0.0,
    last_updated TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
);
-- Initialize for 5 sensors
INSERT INTO flow_readings (sensor_id) VALUES (1), (2), (3), (4), (5);
Use code with caution.

Key Considerations
Calibration: For the YF-S401, 1 Liter is approximately 5880 pulses.
Interrupts: Using IRAM_ATTR ensures the interrupt service routines (ISR) are stored in the ESP32's fast internal RAM.
Resets: The reset logic in the ESP32 code only triggers if httpResponseCode > 0, ensuring no data is lost if the server is down.