Servo button example

servo.ino

#include <Servo.h>

// Declear the servo
Servo myservo;
// Declear pins
const int buttonPin = 2;
const int servoPin = 13;
// Declear variables
int lastButtonState = LOW; 
int bottonState = LOW;
// use in control flow
int mode = 0; // current mode
int angle = 0; //current angle
bool forward = true; // turning direction

// Setup function
void setup() {
  // initialize the pin
  pinMode(servoPin, OUTPUT);
  pinMode(buttonPin, INPUT);
  // attach to servo
  myservo.attach(servoPin);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the button state from pin
  bottonState = digitalRead(buttonPin);
  // check if button change state for sure
  if (bottonState == HIGH && lastButtonState == LOW) {
    // change mode
    if (mode <= 2) {
      mode++;
    } else {
      // if mode is over 3, reset it.
      mode = 0;
    }
    // make sure button works by putting delay to make sure it did not repeated
    delay(30);
  }
  // make sure to change the last button state
  lastButtonState = bottonState;
  
  // start running the mode
  switch (mode) {
      case 0: // reset to 0 angle
        angle = 0;
        break;
      case 1: // set to 90 angle
        angle = 90;
        break;
      case 2: //moving forward and backward by 10
        if (forward == true) {
          angle+=10;
        } else {
          angle-=10;
        }
        delay(30); // slow it down, it might go crazy without it.
        break;
      case 3: //moving forward and backward by 30
        if (forward == true) {
          angle+=30;
        } else {
          angle-=30;
        }
        delay(30); // same
        break;
  }
  // vilidating the angle, make sure it goes between 0 and 180
  if (angle >= 180) {
    angle = 180;
    forward = false;
  }
  if (angle <= 0) {
    angle = 0;
    forward = true;
  }
  
  // Final result goes to the servo
  myservo.write(angle);
}