通过蓝牙连接RaspberryPi与Android并传输WiFi配置文件的技术咨询

一、树莓派端：一次性SSH脚本完成全配置 #

因为最终仅能通过SSH执行一次脚本，且后续无网络，脚本需包含所有依赖安装、蓝牙配置、接收服务部署：

• 安装蓝牙依赖（初始联网时完成，脚本执行时自动处理）：

  sudo apt update && sudo apt install -y bluez bluez-tools python3-bluez
  

• 持久化蓝牙可发现/可配对：
  修改蓝牙配置文件，确保树莓派始终处于可被安卓发现的状态：

  sudo sed -i 's/#DiscoverableTimeout = 0/DiscoverableTimeout = 0/' /etc/bluetooth/main.conf
  sudo sed -i 's/#PairableTimeout = 0/PairableTimeout = 0/' /etc/bluetooth/main.conf
  sudo systemctl restart bluetooth
  

• 部署WiFi配置接收服务：
  脚本内嵌Python监听逻辑，接收安卓发来的WiFi配置并写入系统文件：
  1. 先写入接收脚本到树莓派：

  cat << 'EOF' > /home/pi/wifi_config_receiver.py
  import bluetooth
  import subprocess
  import json
  
  server_sock = bluetooth.BluetoothSocket(bluetooth.RFCOMM)
  server_sock.bind(("", bluetooth.PORT_ANY))
  server_sock.listen(1)
  
  port = server_sock.getsockname()[1]
  uuid = "00001101-0000-1000-8000-00805F9B34FB"
  
  bluetooth.advertise_service(server_sock, "WiFiConfigServer", service_id=uuid)
  
  print(f"Waiting for Android connection on RFCOMM port {port}")
  try:
      client_sock, client_info = server_sock.accept()
      print(f"Connected to {client_info}")
  
      data = client_sock.recv(1024).decode('utf-8')
      if not data:
          raise ValueError("Empty config data received")
  
      config = json.loads(data)
      ssid = config.get('ssid')
      password = config.get('password')
      if not ssid or not password:
          raise ValueError("Invalid WiFi config")
  
      # 写入WiFi配置文件
      config_entry = f'\nnetwork={{\n    ssid="{ssid}"\n    psk="{password}"\n}}'
      with open('/etc/wpa_supplicant/wpa_supplicant.conf', 'a') as f:
          f.write(config_entry)
  
      # 重启网络服务生效
      subprocess.run(["sudo", "systemctl", "restart", "wpa_supplicant"], check=True)
      print("WiFi config applied successfully")
  except Exception as e:
      print(f"Error: {str(e)}")
  finally:
      if 'client_sock' in locals():
          client_sock.close()
      server_sock.close()
      print("Socket closed")
  EOF
  

  2. 设置开机自启，确保树莓派重启后自动监听：

  sudo cat << EOF > /etc/systemd/system/wifi-config-bt.service
  [Unit]
  Description=Bluetooth WiFi Config Receiver
  After=bluetooth.service
  
  [Service]
  ExecStart=/usr/bin/python3 /home/pi/wifi_config_receiver.py
  User=pi
  Restart=always
  
  [Install]
  WantedBy=multi-user.target
  EOF
  sudo systemctl daemon-reload
  sudo systemctl enable wifi-config-bt.service
  

• 将以上所有命令整合成一个脚本，通过SSH一次性执行，执行后树莓派无需网络即可运行蓝牙监听服务。

二、安卓端：应用实现蓝牙发起连接与配置传输 #

安卓应用需完成蓝牙扫描、配对、RFCOMM连接、配置发送四个核心步骤：

• 权限配置（AndroidManifest.xml）：

  <uses-permission android:name="android.permission.BLUETOOTH" android:maxSdkVersion="30" />
  <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" android:maxSdkVersion="30" />
  <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" android:maxSdkVersion="30" />
  <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
  <uses-permission android:name="android.permission.BLUETOOTH_SCAN" />
  

• 核心逻辑（Kotlin示例）：
  1. 扫描树莓派设备：

  private fun scanBluetoothDevices() {
      val bluetoothAdapter = BluetoothAdapter.getDefaultAdapter()
      if (!bluetoothAdapter.isEnabled) {
          // 提示用户开启蓝牙
          return
      }
      val scanner = bluetoothAdapter.bluetoothLeScanner
      scanner.startScan(object : ScanCallback() {
          override fun onScanResult(callbackType: Int, result: ScanResult?) {
              result?.device?.let { device ->
                  if (device.name == "raspberrypi") { // 过滤树莓派设备
                      scanner.stopScan(this)
                      connectToDevice(device)
                  }
              }
          }
      })
  }
  

  2. 连接并发送配置：

  private fun connectToDevice(device: BluetoothDevice, ssid: String, password: String) {
      val uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB")
      val socket = device.createRfcommSocketToServiceRecord(uuid)
      try {
          socket.connect()
          val outputStream = socket.outputStream
          val configJson = """{"ssid":"$ssid","password":"$password"}"""
          outputStream.write(configJson.toByteArray(Charsets.UTF_8))
          outputStream.flush()
          // 提示用户发送成功
      } catch (e: IOException) {
          // 处理连接/发送失败
      } finally {
          socket.close()
      }
  }
  

• 注意事项：处理蓝牙配对请求（安卓端会弹出配对提示，用户确认后即可连接），添加网络权限适配不同安卓版本。

三、验证流程 #

1. 树莓派执行一次性SSH脚本，完成所有配置后重启
2. 安卓应用开启蓝牙，扫描并配对树莓派
3. 输入WiFi SSID和密码，发送配置
4. 树莓派自动写入配置并重启网络，完成联网

内容的提问来源于stack exchange，提问作者Nihon