const int buttonPin = 15; // 按鈕連接 D15 
const int relayPin = 4; // Relay 連接 D4
boolean buttonState = true; // 按鈕放開狀態

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  // 定義此元件為 PULL_UP
  pinMode( relayPin, OUTPUT); // 設定腳位為輸出
  pinMode(buttonPin, INPUT_PULLUP);
}

void loop() {
  // 讀取按鈕狀態
  if (digitalRead(buttonPin) == LOW) {
    buttonState =!buttonState;
    if (buttonState == false) {
      Serial.println("Button is pressed");
      digitalWrite(relayPin, LOW);
      Serial.println("LED is OFF!");
    }
    // 表示按鈕放開即持續放開
    else {
      digitalWrite(relayPin, HIGH);
      Serial.println("LED is ON!");
    }
    delay(200); // 設置延遲 200ms，防機械彈跳
  }
}