Wokwi - Online ESP32, STM32, Arduino Simulator

#include <WiFi.h>
#include <WebServer.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include "ThingSpeak.h"

// WiFi credentials
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// ThingSpeak details
WiFiClient client;
unsigned long myChannelNumber = ;   // Replace with your ThingSpeak channel number
const char * myWriteAPIKey = "";       // Replace with your Write API Key

// Web server
WebServer server(80);

// Sensor pins
#define ONE_WIRE_BUS 4  // DS18B20 pin
const int phPin = 34;
const int tdsPin = 35;
const int turbidityPin = 32;

OneWire oneWire(ONE_WIRE_BUS);
DallasTemperature sensors(&oneWire);

float phValue, tdsValue, turbidityValue, temperature;
String waterStatus;

// Function to check water quality
void checkWaterStatus() {
  if (phValue >= 6.5 && phValue <= 8.5 &&
      tdsValue <= 500 &&
      turbidityValue <= 5 &&
      temperature >= 20 && temperature <= 35) {
    waterStatus = "SAFE";
  } else {
    waterStatus = "UNSAFE";
  }
}

// Handle webpage request
void handleRoot() {
  String html = "<!DOCTYPE html><html><head><title>Water Quality</title>";
  html += "<style>body{font-family:Arial;text-align:center;} .safe{color:green;font-size:24px;} .unsafe{color:red;font-size:24px;}</style></head><body>";
  html += "<h1>Water Quality Monitor</h1>";
  html += "<p>Temperature: " + String(temperature, 2) + " °C</p>";
  html += "<p>pH: " + String(phValue, 2) + "</p>";
  html += "<p>TDS: " + String(tdsValue, 2) + " ppm</p>";
  html += "<p>Turbidity: " + String(turbidityValue, 2) + " NTU</p>";
  html += "<p class='" + (waterStatus=="SAFE"?"safe":"unsafe") + "'>Status: " + waterStatus + "</p>";
  html += "</body></html>";
  server.send(200, "text/html", html);
}

void setup() {
  Serial.begin(115200);
  sensors.begin();

  // Connect WiFi
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500); Serial.print(".");
  }
  Serial.println("\nWiFi Connected! IP Address: ");
  Serial.println(WiFi.localIP());

  // Start ThingSpeak
  ThingSpeak.begin(client);

  // Start web server
  server.on("/", handleRoot);
  server.begin();
}

void loop() {
  // Read sensors
  sensors.requestTemperatures();
  temperature = sensors.getTempCByIndex(0);
  phValue = analogRead(phPin) * (14.0 / 4095.0);
  tdsValue = analogRead(tdsPin) * (1000.0 / 4095.0);
  turbidityValue = analogRead(turbidityPin) * (100.0 / 4095.0);

  checkWaterStatus();

  // Print on Serial Monitor
  Serial.printf("Temp: %.2f °C | pH: %.2f | TDS: %.2f ppm | Turbidity: %.2f NTU | Status: %s\n",
                temperature, phValue, tdsValue, turbidityValue, waterStatus.c_str());

  // Send data to ThingSpeak
  ThingSpeak.setField(1, temperature);
  ThingSpeak.setField(2, phValue);
  ThingSpeak.setField(3, tdsValue);
  ThingSpeak.setField(4, turbidityValue);

  int x = ThingSpeak.writeFields(myChannelNumber, myWriteAPIKey);
  if (x == 200) {
    Serial.println("Data sent to ThingSpeak!");
  } else {
    Serial.println("Error sending data to ThingSpeak!");
  }

  // Handle webpage requests
  server.handleClient();

  delay(15000);  // ThingSpeak requires min 15s interval
}