Main.ino

#include <SoftwareSerial.h>

String apiKey = "API KEY"; // Your Api key
SoftwareSerial ser(10, 11); // TX, RsX

int trigPin = 6; 
int echoPin = 5; 
long rate=0;
long preread=0;
long counter =0;
int object=0;
float halfval=0;

void setup() {     
    Serial.begin(115200);
    pinMode(trigPin, OUTPUT);
    pinMode(echoPin, INPUT);  
    ser.begin(115200);  
    ser.println("AT+RST");
}

void loop() {
      long duration, distance;
      counter ++;      
      digitalWrite(trigPin,HIGH);
      delayMicroseconds(1000);
      digitalWrite(trigPin, LOW);
      duration=pulseIn(echoPin, HIGH);
      distance =(duration/2)/29.1;
      Serial.print("Counter = ");
      Serial.println(counter);
      Serial.print(distance);
      Serial.println("CM");
      delay(500);  
     if(counter %2 !=0)
     {
      rate=distance-preread;
      preread=distance;
      halfval= preread/2;
      
     }
      Serial.print("halfval = ");
      Serial.println(halfval);
       if(distance<=halfval)
      {
            object=2;            
            distance=50;
            rate=0;
      }
      String state1=String(distance); 
      String state2=String(rate);
      String state3=String(counter);
      String state4=String(object); 

      String cmd = "AT+CIPSTART=\"TCP\",\"";
      cmd += "184.106.153.149"; // api.thingspeak.com
      cmd += "\",80";
      ser.println(cmd);
      Serial.println(cmd); 
      
      String getStr = "GET /update?api_key=";
      getStr += apiKey;  
      getStr +="&field1=";
      getStr += String(state1);  
      getStr +="&field2=";
      getStr += String(state2);
      getStr +="&field3=";
      getStr += String(state3);
      getStr +="&field4=";
      getStr += String(state4);
      getStr += "\r\n\r\n";

      cmd = "AT+CIPSEND=";
      cmd += String(getStr.length());
      ser.println(cmd);
      Serial.println(cmd);
      ser.print(getStr);
      Serial.print(getStr); 
       object --;  
      delay(16000); 
}