const byte xPin = A0, yPin = A1, buttonPin = 2;
int centerX = 512, centerY = 512;
const int deadZone = 35;
unsigned long reportedAt = 0;

int axisValue(int raw, int center) {
  const int offset = raw - center;
  if (abs(offset) <= deadZone) return 0;
  if (offset > 0) {
    return constrain(map(raw, center + deadZone, 1023, 0, 100), 0, 100);
  }
  return constrain(map(raw, 0, center - deadZone, -100, 0), -100, 0);
}

void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
  Serial.begin(9600);
  Serial.println("Release the stick; center calibration starts in 2 seconds");
  delay(2000);
  long xSum = 0, ySum = 0;
  for (byte i = 0; i < 64; ++i) {
    xSum += analogRead(xPin); ySum += analogRead(yPin); delay(5);
  }
  centerX = constrain(xSum / 64, deadZone + 1, 1022 - deadZone);
  centerY = constrain(ySum / 64, deadZone + 1, 1022 - deadZone);
}

void loop() {
  const unsigned long now = millis();
  if (now - reportedAt < 100) return;
  reportedAt = now;
  Serial.print("x="); Serial.print(axisValue(analogRead(xPin), centerX));
  Serial.print(" y="); Serial.print(axisValue(analogRead(yPin), centerY));
  Serial.print(" pressed="); Serial.println(digitalRead(buttonPin) == LOW ? 1 : 0);
}