ESP32 using A02YYUW

This works fine for interfacing an ESP32 to the A02YYUW  Ultrasonic Sensor…

//The ESP32 knows that Serial2 pins are RX=16 and TX=17

unsigned char data[4]={};
float distance;

void setup()
{
 Serial.begin(115200);
 Serial2.begin(9600); 
 delay(3000);
 Serial.println("Starting");
}

void loop()
{
 if(Serial2.read()==0xff)
 {
   data[0] = 0xff;
   for(int i=1;i<4;i++)
   {
     data[i]=Serial2.read();
   }

   int sum;
   sum=(data[0]+data[1]+data[2])&0x00FF;
   if(sum==data[3])
   {
     distance=(data[1]<<8)+data[2];
     Serial.print("distance=");
     Serial.print(distance/10);
     Serial.println("cm");
   }
   
 }
 
 data[0] = 0x00;
 Serial2.flush();
 delay(100);
 
}