#include <WiFi.h>          // WiFi library for ESP32
#include <HTTPClient.h>     // HTTPClient library for making HTTP requests

// Define analog sensor pin (use the correct GPIO pin number)
#define ANALOG_SENSOR_PIN 34  // GPIO pin for analog input

// Define weight threshold (2500 kg)
const float weightThreshold = 2500;  // Weight in kg
// Define alarm pin
#define ALARM_PIN 2

// Calibration factor to convert analog reading to weight
const float calibrationFactor = 0.01 * (5500 / 50.0); // Adjust based on sensor

// ThingSpeak credentials
const char* ssid = "Wokwi-GUEST";            // Your Wi-Fi network SSID
const char* password = "";    // Your Wi-Fi network password
const char* server = "http://api.thingspeak.com";  // ThingSpeak server
const char* apiKey = "1YK6YMY3VD4JIEUO";  // Your ThingSpeak Write API Key

void setup() {
  Serial.begin(115200); // Initialize serial communication
  pinMode(ANALOG_SENSOR_PIN, INPUT); // Set analog sensor pin as input
  pinMode(ALARM_PIN, OUTPUT); // Set alarm pin as output
  digitalWrite(ALARM_PIN, LOW); // Ensure buzzer is off at startup

  // Connect to Wi-Fi
  Serial.print("Connecting to Wi-Fi");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print(".");
  }
  Serial.println(" Connected!");
}

void loop() {
  // Read weight from analog sensor
  int sensorValue = analogRead(ANALOG_SENSOR_PIN);

  // Convert sensor value to weight
  float weight = sensorValue * calibrationFactor;

  // Print weight to serial monitor
  Serial.print("Weight: ");
  Serial.print(weight);
  Serial.println(" kg");

  // Send weight to ThingSpeak via HTTP request
  if (WiFi.status() == WL_CONNECTED) { // Check Wi-Fi connection
    HTTPClient http;
    String url = String(server) + "/update?api_key=" + apiKey + "&field1=" + String(weight);
    http.begin(url);
    int httpResponseCode = http.GET();

    if (httpResponseCode > 0) {
      Serial.println("Data sent to ThingSpeak successfully!");
    } else {
      Serial.print("Error sending data to ThingSpeak. HTTP error code: ");
      Serial.println(httpResponseCode);
    }

    http.end(); // Close connection
  }

  // Check if the weight exceeds the threshold
  if (weight >= weightThreshold) {
    digitalWrite(ALARM_PIN, HIGH);  // Turn on the buzzer
    Serial.println("Overload detected! Buzzer ON.");
    tone(ALARM_PIN, 3000); // Play a 3000 Hz tone on the buzzer
  } else {
    digitalWrite(ALARM_PIN, LOW);   // Turn off the buzzer
    noTone(ALARM_PIN); // Stop any tone that might be playing
  }

  delay(20000); // Wait for 20 seconds before the next reading (as per ThingSpeak's limit)
}