const byte top=A5;
const byte right=A4;
const byte left=A3;
const byte bottom=A2;

int top_value;
int right_value;
int left_value;
int bottom_value;

void setup() {

  pinMode(top, INPUT);
  pinMode(right, INPUT);
  pinMode(left, INPUT);
  pinMode(bottom, INPUT);

  Serial.begin(9600);

}

void move_left(){
  Serial.println("Move left");
}

void move_right(){
  Serial.println("Move right");
}

void move_up(){
  Serial.println("Move up");
}

void move_down(){
  Serial.println("Move down");
}

void loop() {

  top_value=analogRead(top);
  right_value=analogRead(right);
  left_value=analogRead(left);
  bottom_value=analogRead(bottom);

  if (top_value<bottom_value){
    move_up();
  }
  else if(top_value>bottom_value){
    move_down();
  }  
  
  if (right_value<left_value){
    move_right();
  }
  else if(right_value>left_value){
    move_left();
  }

  delay(500);
}