#include <WiFi.h>
#include <PubSubClient.h>
#include <NewPing.h>
// Replace with your own WiFi credentials 
const char* ssid = "your_SSID"; 
const char* password = "your_PASSWORD";
// Replace with your own
#include <SoftwareSerial.h> 
#include <WiFi.h> 
#include <PubSubClient.h>
// WiFi credentials
const char* SSID = "your_wifi_ssid"; 
const char* PASSWORD = "your_wifi_password";
// IBM Cloud credentials
const char* ORG = "zp8kep";
const char* DEVICE_TYPE = "abcd";
const char* DEVICE_ID = "1234";
const char* AUTH_TOKEN= "12345678";
const char* SERVER = "your_server_url";
// MQTT topics
const char* EVENT_TOPIC= "iot-2/evt/status/fmt/ json"; 
const char* COMMAND_TOPIC= "iot-2/cmd/led/ fmt/json";
// Ultrasonic sensor pins 
const int TRIGGER_PIN = 1; 
const int ECHO_PIN = 2;
WiFiClientSecure wifiClient; 
PubSubClient mqttClient (wifiClient);
void connectWiFi() 
{
WiFi.begin(SSID, PASSWORD); 
while (WiFi.status() != WL_CONNECTED) 
{ 
 delay(1000); 
 Serial.println("Connecting to WiFi...");
} 
 Serial.println("Connected to WiFi");
}
void connectMqtt() {
mqttClient.setServer (SERVER, 8883); 
mqttClient.setBufferSize(1024); 
mqttClient.setCallback(callback);
// Connect to MQTT Broker while (!mqttClient.connected()) 
{ 
  Serial.println("Connecting to MQTT Broker..."); 
  mqttClient.connect(DEVICE_ID, DEVICE_TYPE,AUTH_TOKEN); 
  delay(1000);

} 
Serial.println("Connected to MQTT Broker"); 
mqttClient.subscribe (COMMAND_TOPIC); 
}

void callback(char* topic, byte* payload, unsigned int length) { 
  // Handle incoming MQTT messages 
  }
  long measure Distance() 
  { 
    digitalWrite(TRIGGER_PIN, LOW);
    delayMicroseconds(2); 
    digitalWrite(TRIGGER_PIN, HIGH);
    delayMicroseconds(10);
    digitalWrite(TRIGGER_PIN,LOW);

    long duration = pulseln (ECHO_PIN, HIGH); 
    long distance = duration * 0.034/2;

    return distance;

}

void setup() {

Serial.begin(9600); 
pinMode(TRIGGER_PIN, OUTPUT); 
pinMode(ECHO_PIN, INPUT);

connectWiFi(); 
connectMqtt();

}

void loop() {
 long distance = measure Distance(); 
 Serial.println(distance);

 if (distance < 100) {

// Create JSON payload with distance value String payload= "{\"d\":{\"distance\":" +String(distance) +"}}"; 
// Publish MQTT event mqttClient.publish(EVENT_TOPIC, payload.c_str());

Serial.println("Distance uploaded to IBMCloud");

}

mqttClient.loop(); // Maintain MQTT connection 
delay(1000); // Wait for 1 second

}