#include <Servo.h>

unsigned long dur_t, start_t;
Servo arm; 
float pos = 0.0;
float step = 30.0; 
bool buttonPressed = false; 

void setup() {
  pinMode(4, INPUT_PULLUP); 
  arm.attach(3); 
  arm.write(pos); 
}

void loop() {
  if (digitalRead(4) == LOW && !buttonPressed) { 
    buttonPressed = true; 
    delay(50); 
    start_t = millis(); 
  }

  if (digitalRead(4) == HIGH && buttonPressed) {
    dur_t = millis() - start_t; 
    buttonPressed = false; 

    if (dur_t < 300) { 
      rotateClockwise();
    } else { 
      rotateAntiClockwise();
    }
  }
}

void rotateClockwise() {
  if (pos <= 150.0) { 
    pos = pos+step; 
    arm.write(pos); 
    delay(100); 
  }
}

void rotateAntiClockwise() {
  if (pos >= 30.0) { 
    pos = pos-step; 
    arm.write(pos); 
    delay(100); 
  }
}