#include <WiFi.h>
#include
<pubsubClient.h>
void callback(char* subscribetopic,byte* payload,unsigned int payloadLength);
//--------credentials of IBM Accounts----
#define ORG "kotoq5"//IBM ORGANITION ID
#define  DEVICE-TYPE"ESP32"//Device type mentioned in ibm watson IOT platform
#define DEVICE-ID"12345"//Device ID mentioned in ibm watson IOT platform
#define TOKEN"12345678"//Token
String data3;
char server[]=ORG".messaging.internetofthings.ibmcloud.com";
char publishTopic[]="iot-2/evt/data/fmt/json";
char subscibetopic[]="iot-2/cmd/test/fmt/string";
char authMethod[]="use-token-auth";
char token[]=TOKEN;
char clientId[]="d:"ORG":"DEVICE_TYPE":"DEVICE_ID;
wificlient wificlient;
pubsubClient client(server,1883,callback,wifiCient);
const int trigpin=5;
const int echopin=18;
#define SOUND_SPEED 0.034
long duration;float distance;
void setup(){  
  Serial.begin(115200);
  pinMode(trigpin, OUTPUT);
  pinMode(echopin, INPUT);
  wificonnect();
  mqttconnect();
}
void loop(){
  digitalWrite(trigpin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigpin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigpin, LOW);
  duration=pulseIn(echopin,HIGH);
  distance=duration*SOUND_SPEED/2;
  Serial.print("Distance (cm): ");
  Serial.println(distance);
   if(distance<100)
   {
     Serial.println("ALERT!!");
      delay(1000);PublishData(distance);
      delay(1000); if (!client.loop()) {
      mqttconnect();
}}
delay(1000);
}
void PublishData(float dist) {
  mqttconnect();
  String payload = "{\"Distance\":";
  payload += dist;
  payload += ",\"ALERT!!\":""\"Distance less than 100cms\"";
  payload += "}";
  Serial.print("Sending payload: ");
  Serial.println(payload);
  if (client.publish(publishTopic, (char*) payload.c_str())) {
  Serial.println("Publish ok");
  } else {
  Serial.println("Publish failed");
  } } void mqttconnect() {
  if (!client.connected())
  {
   Serial.print("Reconnecting client to ");
   Serial.println(server);
   while (!!!client.connect(clientId, authMethod, token)) {
   Serial.print(".");
   delay(500);
   }initManagedDevice();
   Serial.println();
   }
   }
   void wificonnect()
   {
    Serial.println();
    Serial.print("Connecting to ");
    WiFi.begin("Wokwi-GUEST", "", 6); while
    (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
    }
    Serial.println("");
    Serial.println("WiFi connected");
    Serial.println("IP address: ");
    Serial.println(WiFi.localIP());
    }
    void initManagedDevice()
    { if (client.subscribe(subscribetopic)) {
    Serial.println((subscribetopic));
    Serial.println("subscribe to cmd OK");
    }
    else
    {
    Serial.println("subscribe to cmd FAILED");
    }
    }
    void callback(char* subscribetopic,byte* payload,unsigned int payloadLength)
    {
    Serial.print("callback invoked for topic:");
    Serial.println(subscribetopic);
    for(int i = 0;i < payloadLength; i++)
    {//serial.print((char)payload[i]);
    data3 += (char)payload[i];
    }
    Serial.println("data:" + data3);
    data3="";
    }