const int switchPin = 5;
const int triggerPin = 2;
const int echoPin = 4;
const int servoPin = 7;
const int controlPin = 6;

#include <Servo.h>
Servo myServo;

void setup() {
  pinMode(triggerPin, OUTPUT);  // define Arduino pin for trigger
  pinMode(echoPin, INPUT);      // define Arduino pin for echo
  Serial.begin(9600);           // enable serial monitor
  pinMode(switchPin, INPUT);
  myServo.attach(servoPin);
}

void loop() {

  int sensorValue = analogRead(A0);
  float voltage = sensorValue * (5.0 / 1023.0);
  float y = voltage / 5;

  // Send trigger pulse
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);

  long t = pulseIn(echoPin, HIGH);  // input pulse and save it to variable

  long inches = t / 74 / 2; // time convert distance to inches
  long cm = t / 29 / 2;     // time convert distance to cm

  String inch = " inches";
  String CM = " cm";

  while (digitalRead(switchPin) == HIGH) {
    float x = 90 * y;
    float a = 90 - x;
    float b = 90 + x;

    for (int i=a;i<=b;i++) {
      myServo.write(i);
      delay(5);
      Serial.print(inches);
      Serial.print(inch);
      Serial.print(" (");
      Serial.print(cm);
      Serial.print(CM);
      Serial.println(")");
    }

    for (int i=b;i>=a;i--) {
      myServo.write(i);
      delay(5);
      Serial.print(inches);
      Serial.print(inch);
      Serial.print(" (");
      Serial.print(cm);
      Serial.print(CM);
      Serial.println(")");
    }
  }

  if (digitalRead(controlPin) == HIGH) {
    float c = 180 * y;
    myServo.write(c);
      Serial.print(inches);
      Serial.print(inch);
      Serial.print(" (");
      Serial.print(cm);
      Serial.print(CM);
      Serial.println(")");
  }
}