#include <Servo.h>

Servo servo;
int btnStart = PIN4;
int btnStop = PIN7;

uint8_t isServoOn = HIGH;

void setup() {
  servo.attach(2);
  pinMode(btnStart, INPUT_PULLUP);
  pinMode(btnStop, INPUT_PULLUP);
}

void loop() {
  if (digitalRead(btnStart) == LOW) {
    isServoOn = HIGH;
  }

  if (digitalRead(btnStop) == LOW) {
    isServoOn = LOW;
  }

  if (isServoOn) {
    servo.write(0);
    delay(750);
    servo.write(180);
    delay(750);
  }
}