#include <Servo.h>

#define stepAngle 45

Servo myservo;

int pos = 0;
int oldPos = 180;
char recievedChar;

void setup() {
  Serial.begin(9600);
  myservo.attach(6);
  
  for(int i = oldPos; i <= pos; i++) {
    myservo.write(i);
    delay(20);
  }
}

void loop() {

  if(Serial.available()){
     int tmpPos = Serial.read();
     if(tmpPos) {
  
      switch(tmpPos) {
        case 'A':  
          pos = 0;
          break;
        case 'B':  
          pos = stepAngle * 1;
          break;
        case 'C':  
          pos = stepAngle * 2;
          break;
        case 'D':  
          pos = stepAngle * 3;
          break;
        case 'E':  
          pos = stepAngle * 4;
          break;
      }
  
      if(oldPos < pos) {
        for(int i = oldPos; i <= pos; i++) {
          myservo.write(i);
          delay(10);
        }
      } else {
        for(int i = oldPos; i > pos; i--) {
          myservo.write(i);
          delay(10);
        }
      } 
      

        /*
        Serial.print(oldPos);
        Serial.print("\t");
        Serial.print(pos);
        Serial.print("\t");
        Serial.println(tmpPos);
        */
        
        oldPos = pos;
     }

  }

  //Serial.flush();

}