ESP8266如何将引脚D1和接地引脚连接到墙壁开关？

我刚刚开始使用 ESP8266 的第一个项目，也很高兴知道我对这类项目没有太多的电子知识。我尝试做的是以下内容。我想将引脚 D1 和接地引脚连接到墙壁开关（通常用于打开或关闭灯）。如果墙壁开关的状态发生变化，我想改变一个 philips hue 灯的状态（意思是：如果灯熄灭，那么如果按下墙壁开关我想打开它，反之亦然）。
ESP8266的代码是：
代码：全选#include
#include

// Wifi Settings
const char* ssid = "xxxxx";
const char* password = "xxxxx";

// Hue Settings

const char hueHubIP[] = "xxxxx"; // Hue Bridge IP
const int hueHubPort = 80;
const char hueUsername[]="xxxxxx";
String light="1";

// Commands

String hue_on="{\"on\":true}";
String hue_off="{\"on\":false}";

boolean state = false; // for monitoring switch state changes
boolean previousState; // ditto
boolean onOffState = false;   // To store actual on/off state of light as reported by Hue bridge
int switchPin = 5; // -- control sense pin, mapped to D1 on NodeMCU

WiFiClient client;

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);     // Initialize LED_BUILTIN pin as output

  Serial.begin(9600);
  pinMode(switchPin, INPUT_PULLUP);
  delay(10);

  // We start by connecting to a WiFi network
  Serial.println();
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.begin(ssid, password);
  
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());

  previousState = digitalRead(switchPin);
  digitalWrite(LED_BUILTIN, HIGH);
  Serial.println("State Switch:");
  Serial.println(previousState);
}

void loop() {
  state = digitalRead(switchPin); // for checking for state change

  if (state != previousState) // state change
  {
    previousState == state;
   
    getHue();
    delay(500);
   
    if (onOffState == true)                         // If lights are on, send "Off" command
    {
      Serial.println("");
      Serial.print("Switch lamp off");
      String command =  "{\"on\": false}";
      setHue(command);
      digitalWrite(LED_BUILTIN, LOW);
    }
    else                                            // If lights are off, send "On" command
    {
      Serial.println("");
      Serial.print("Switch lamp on");
      String command =  "{\"on\": true}";
      setHue(command);
      digitalWrite(LED_BUILTIN, HIGH);
    }
  }
}


void setHue(String command)
{
  if (client.connect(hueHubIP, hueHubPort))
  {
    client.print("PUT /api/");
    client.print(hueUsername);
    client.print("/lights/");
    client.print(light);
    client.println("/state HTTP/1.1");
    client.println("keep-alive");
    client.print("Host: ");
    client.println(hueHubIP);
    client.print("Content-Length: ");
    client.println(command.length());
    client.println("Content-Type: text/plain;charset=UTF-8");
    client.println();                             // Blank line before body
    client.println(command);
    client.stop();
  }
}

void getHue()
{
  if (client.connect(hueHubIP, hueHubPort))
  {
    client.print("GET /api/");
    client.print(hueUsername);
    client.print("/lights/");
    client.print(light);
    client.println(" HTTP/1.1");
    client.print("Host: ");
    client.println(hueHubIP);
    client.println("Content-type: application/json");
    client.println("keep-alive");
    client.println();
    while (client.connected())
    {
      if (client.available())
      {
        client.findUntil("\"on\":", "\0");
        onOffState = (client.readStringUntil(',') == "true");
        break;
      }
    }
    client.stop();
  }
}


当我测试此设置并将引脚 D1 接地时，D1 的状态似乎不断变为高/低（而电线仍接地）。我不知道为什么会这样。
任何地方都可以帮助我并告诉我我做错了什么吗？我不应该将 D1 连接到地面，而是以其他方式连接吗？还是我的编码错了？