#include <Servo.h>
#include <SoftwareSerial.h>

SoftwareSerial Serial(PB1, PB2);

Servo myServo;
int servoPin = 0;
int servoPos;

int openPose = 0;
int closedPose = 90;
int trigPin = 3;
int echoPin = 4;
int travelTime;
int distance;

void setup() {
  // put your setup code here, to run once:
  myServo.attach(servoPin);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
Serial.begin(9600);
}

void loop() {
  // put your main code here, to run repeatedly:
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  travelTime = pulseIn(echoPin, HIGH);
  distance = 0.034 * travelTime/2;

if(distance < 20) {
  Serial.print(distance);
  Serial.println("");
  myServo.write(90);
  delay(2000);
} else {
  Serial.print(distance);
Serial.println("");
  myServo.write(180);
}
}