Touchless Doorbell

#define SECRET_SSID    "Anmol-4g"
#define SECRET_PASS    "sark@1968"
#define CHANNEL_ID     CID
#define WRITE_APIKEY   "KEY"
#define TRIGGER D7
#define ECHO  D8
#include <LiquidCrystal_I2C.h>
#include "ThingSpeak.h"

LiquidCrystal_I2C lcd(0x27, 16, 2);
unsigned long myChannelNumber =  1894990;
const char * myWriteAPIKey = "TIBX52T8E173RFDR";

#include <ESP8266WiFi.h>

char ssid[] = SECRET_SSID;   // your network SSID (name)
char pass[] = SECRET_PASS;   // your network password
int keyIndex = 0;            // your network key index number (needed only for WEP)
const int REF_VIN=3.3; 
int i=0;
int count=0;
const int buzzer = D3;
WiFiClient  client;

void setup() {
  Serial.begin(115200);
  pinMode(TRIGGER, OUTPUT);
  pinMode(ECHO, INPUT);
  pinMode(D0, OUTPUT);//red light
  pinMode(buzzer, OUTPUT);
    lcd.begin();
  lcd.backlight();
  delay(100);
Serial.println();
  WiFi.mode(WIFI_STA);

  ThingSpeak.begin(client);
}

float project()
{
 float voltage= analogRead(A0);
 float tmpVal= {(voltage/1023.0)*REF_VIN*100};
 long duration, distance;
 
 
  digitalWrite(TRIGGER, LOW);  
  delayMicroseconds(2);
  digitalWrite(TRIGGER, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIGGER, LOW);
  duration = pulseIn(ECHO, HIGH);
  distance = (duration/2) / 29.1;
  lcd.clear();
  if(distance <=20) // If the sensor detects an obstacle less than 20 cm in distance, the LED will start to blink.
  {   tone(buzzer, 2000); // Send 1KHz sound signal...
      delay(1000);        // ...for 1 sec
      noTone(buzzer);     // Stop sound...
      delay(1000); 
      
 
  if(tmpVal>54){
      digitalWrite (D0, HIGH);
     lcd.setCursor(4, 0);
    lcd.print("Red Alert: ");
    lcd.setCursor(0,1); //Next Line
    lcd.print("High Temperature");
       
    }
 else{
      digitalWrite (D0, LOW);
    for( i=0;i<=15;i++)
     {
      tone(buzzer, 800); // Send 1KHz sound signal...
      delay(100);        // ...for 1 sec
      noTone(buzzer);     // Stop sound...
      delay(100);
      }
    lcd.setCursor(0, 0);
    lcd.print("Alert:Open Door ");
    lcd.setCursor(5,1); //Next Line
    lcd.print("Normal Temperature");
      count++;
   }
   
   }
  delay(50);
   
  Serial.println(tmpVal);
  //Serial.println("Duration is:  " + String(duration));
  //Serial.print("Distance is:  ");
  //Serial.print(distance);
  //Serial.println("  Centimeter:");
  Serial.print("No of People in Room are : ");
  Serial.println(count);
  return count;
  
  delay(1000);

}

void loop() {
int tempVal;
  // Connect or reconnect to WiFi
  if (WiFi.status() != WL_CONNECTED) {
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(SECRET_SSID);
    while (WiFi.status() != WL_CONNECTED) {
      WiFi.begin(ssid, pass); // Connect to WPA/WPA2 network. Change this line if using open or WEP network
      Serial.print(".");
      delay(5000);
    }
    Serial.println("\nConnected.");
  }

  // Get temperature value from sensor
  tempVal =  project();

  // Write value to Field 1 of a ThingSpeak Channel
  int httpCode = 
  httpCode = ThingSpeak.writeField(myChannelNumber, 1,  tempVal, myWriteAPIKey);


  if (httpCode == 200) {
    Serial.println("Channel write successful.");
  }
  else {
    Serial.println("Problem writing to channel. HTTP error code " + String(httpCode));
  }

  // Wait 20 seconds to update the channel again
  delay(20000);
}