const int joystick_x_pin = A0; 
const int joystick_y_pin = A3;

void setup() {
  Serial.begin(115200);
}

void loop() {
  int x_adc_val, y_adc_val; 
  float x_volt, y_volt;
  x_adc_val = analogRead(joystick_x_pin); 
  y_adc_val = analogRead(joystick_y_pin);
  x_volt = ( ( x_adc_val * 3.3 ) / 4095 );  
  y_volt = ( ( y_adc_val * 3.3 ) / 4095 ); 
  if(x_volt > 3){
    Serial.println("l");
  }
  if(x_volt < 1){
    Serial.println("r");
  }
  if(y_volt > 3){
    Serial.println("u");
  }
  if(y_volt < 1){
    Serial.println("d");
  }
  delay(100);
}