/*
 Controlling a servo position using a potentiometer (variable resistor)
 by Michal Rinott <http://people.interaction-ivrea.it/m.rinott>

 modified on 8 Nov 2013
 by Scott Fitzgerald
 http://www.arduino.cc/en/Tutorial/Knob
*/

#include <Servo.h>

enum State { START, LED_ON_START, LED_ON_END, LED_OFF_START, LED_OFF_END, END };
enum ServoState { READ_PORT, SET_SERVO, WAIT, SERVO_END };

int ledpin = 13;
int ledstate = LOW;
int leddelay = 1000;
int start, ended  = 0;
State state = START;
int relaypin = 12;

class ServoX: Servo {
  public:
    ServoX(int servo_pin, int pot_pin);
    virtual ~ServoX() {}
    void    Init();
    void    Calc();

  private:
    int         m_pin, p_pin;
    ServoState  m_state;
    int         old_val, val;
    int         start_wait, end_wait, duration;
};

ServoX::ServoX(int servo_pin, int pot_pin)
: m_pin(servo_pin), p_pin(pot_pin), old_val(0), val(0), start_wait(0), end_wait(0), duration(15)
{
}

void ServoX::Init() {
  attach(m_pin);
  m_state = READ_PORT;
}

void ServoX::Calc() {
  int mval;

  switch (m_state) {
    case READ_PORT:
      val = analogRead(p_pin);              // reads the value of the potentiometer (value between 0 and 1023)
      if (old_val - val) {
        m_state = SET_SERVO;
      }
      break;
    case SET_SERVO:
      mval = map(val, 0, 1023, 0, 180);     // scale it to use it with the servo (value between 0 and 180)
      write(mval);                          // sets the servo position according to the scaled value
      old_val = val;                         
      m_state = WAIT;
      start_wait = millis();
      break;
    case WAIT:                              // waits for the servo to get there
      end_wait = millis();
      if (end_wait - start_wait > duration) {
        m_state = SERVO_END;
      }
      break;
    case SERVO_END:
      m_state = READ_PORT;
      break;
  }
}

int servo_pin = 9;
int pot_pin = 0;
ServoX myservo(servo_pin, pot_pin);

void setup() {
  myservo.Init();
}

void loop() {
  myservo.Calc();

  switch (state) {
    case START: 
      start = millis();
      state = LED_ON_START;
      break;
    case LED_ON_START:
      ledstate = HIGH;
      digitalWrite(ledpin, ledstate);
      digitalWrite(relaypin, ledstate);
      state = LED_ON_END;
      break;
    case LED_ON_END:
      ended = millis();
      if (ended - start > leddelay) {
        state = LED_OFF_START;
        start = ended;
      }
      break;
    case LED_OFF_START:
      ledstate = LOW;
      digitalWrite(ledpin, ledstate);
      digitalWrite(relaypin, ledstate);
      state = LED_OFF_END;
      break;
    case LED_OFF_END:
      ended = millis();
      if (ended - start > leddelay) {
        state = END;
        start = ended;
      }
      break;
    case END:
      state = START;
      break;
  }
}