#include <Servo.h>

Servo myServo;  // create a servo object
int pos = 0;    // variable to store the servo position

void setup() {
  myServo.attach(9);  // attach the servo to pin 9
  Serial.begin(9600); // initialize serial communication
}

void loop() {
  if (Serial.available() > 0) {    // check if there is incoming serial data
    char input = Serial.read();    // read the incoming byte
    if (input == 'w') {            // if the input is 'w'
      pos = 180;                   // set the servo position to 180 degrees
      myServo.write(pos);          // move the servo to the new position
      delay(500);                  // wait for the servo to finish moving
      pos = 0;                     // reset the servo position to 0 degrees
      myServo.write(pos);          // move the servo back to the original position
    }
  }
}