Sender-ESP

#include <ArduinoIoTCloud.h>
#include <Arduino_ConnectionHandler.h>
#include <WiFiClientSecure.h>
#include <ESP8266WiFi.h>

const char DEVICE_LOGIN_NAME[]  = "8d0e5e21-90d2-474d-b875-5b2f7d15b96a";

//Change the SSID PASS DEVICE_KEY with your credentials.

const char SSID[]               = SECRET_SSID;    // Network SSID (name)
const char PASS[]               = SECRET_OPTIONAL_PASS;    // Network password (use for WPA, or use as key for WEP)
const char DEVICE_KEY[]  = SECRET_DEVICE_KEY;    // Secret device password

void onWaterLevelChange();
void onLightChange();

int waterLevel;
bool light;

void initProperties(){

  ArduinoCloud.setBoardId(DEVICE_LOGIN_NAME);
  ArduinoCloud.setSecretDeviceKey(DEVICE_KEY);
  ArduinoCloud.addProperty(waterLevel, READWRITE, ON_CHANGE, onWaterLevelChange);
  ArduinoCloud.addProperty(light, READWRITE, ON_CHANGE, onLightChange);

}

WiFiConnectionHandler ArduinoIoTPreferredConnection(SSID, PASS);


#define trigger_pin D5
#define Echo_pin D6
long duration;
int distance;

void setup() {
  pinMode(trigger_pin, OUTPUT);
  pinMode(Echo_pin, INPUT);
  Serial.begin(115200);

  // This delay gives the chance to wait for a Serial Monitor without blocking if none is found
  delay(1500); 

  // Defined in thingProperties.h
  initProperties();

  // Connect to Arduino IoT Cloud
  ArduinoCloud.begin(ArduinoIoTPreferredConnection);
  
  /*
     The following function allows you to obtain more information
     related to the state of network and IoT Cloud connection and errors
     the higher number the more granular information you’ll get.
     The default is 0 (only errors).
     Maximum is 4
 */
  setDebugMessageLevel(2);
  ArduinoCloud.printDebugInfo();
}

void loop() {
  ArduinoCloud.update();
  // Your code here 
  digitalWrite(trigger_pin, LOW); //set trigger signal low for 2us
  delayMicroseconds(2);
  digitalWrite(trigger_pin, HIGH);  // make trigger pin active high
  delayMicroseconds(10);            // wait for 10 microseconds
  digitalWrite(trigger_pin, LOW);   // make trigger pin active low
  duration = pulseIn(Echo_pin, HIGH); // save time duration value in "duration variable
  distance= duration*0.034/2; //Convert pulse duration into distance
  Serial.println("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  //int dist = (distance/86) * 100; 
  waterLevel = 100 - ((distance* 100)/100);
  delay(1000);
}

/*
  Since WaterLevel is READ_WRITE variable, onWaterLevelChange() is
  executed every time a new value is received from IoT Cloud.
*/
void onWaterLevelChange()  {
  // Add your code here to act upon WaterLevel change
}

/*
  Since LIGHT is READ_WRITE variable, onLIGHTChange() is
  executed every time a new value is received from IoT Cloud.
*/
void onLIGHTChange()  {
  // Add your code here to act upon LIGHT change
}


void onLightChange()  {
  // Add your code here to act upon Light change
}