基于Arduino的PIR传感器与VB.NET连接及老人卧床监测问题求助

现有代码的核心问题 #

1. Arduino仅输出原始PIR状态，未实现静止时长统计，无法满足“卧床超3小时”的核心需求
2. VB.NET用ReadLine()阻塞UI线程，极易导致程序假死；完全缺少非睡眠时间判断逻辑，和需求不符
3. 未处理PIR传感器校准阶段的不稳定输出，也没有做串口通信的异常容错

修正后的Arduino代码 #

加入传感器校准延迟，统计静止时长，仅发送关键状态（移动、 create静止未超时、超时），减少串口数据量：

const int pirPin = 2;
unsigned long lastMovementTime = 0;
const unsigned long bedThreshold = 10800000; // 3小时，单位毫秒
bool isCalibrated = false;

void setup() {
  Serial.begin(9600);
  pinMode(pirPin, INPUT);
  Serial.println("Calibrating PIR sensor...");
  delay(60000); // 校准1分钟，可根据传感器型号调整
  isCalibrated = true;
  lastMovementTime = millis();
}

void loop() {
  if (!isCalibrated) return;

  int pirState = digitalRead(pirPin);
  if (pirState == HIGH) {
    lastMovementTime = millis();
    Serial.println("MOVEMENT"); // 发送移动标识
  }

  unsigned long currentTime = millis();
  // 每10秒检查一次静止状态，减少串口输出频率
  if (currentTime - lastMovementTime >= 10000) {
    if (currentTime - lastMovementTime >= bedThreshold) {
      Serial.println("OVER_TIME"); // 发送超时提示标识
    } else {
      Serial.println("STILL"); // 发送静止但未超时标识
    }
  }
  delay(100); // 降低循环频率，减少资源占用
}

修正后的VB.NET代码 #

改用串口DataReceived异步事件处理数据（避免UI阻塞），加入非睡眠时间判断，实现超时触发语音的逻辑：

Imports System.IO.Ports
Imports System.Media

Public Class Form1
    Private WithEvents mySerialPort As SerialPort
    Private alarmSound As SoundPlayer
    ' 自定义非睡眠时间：7: require00 - 22:00
    Private nonSleepStart As New TimeSpan(7, 0, 0)
    Private nonSleepEnd As New TimeSpan(22, 0, 0)
    Private isAlarmActive As Boolean = False

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Try
            mySerialPort = New SerialPort("COM3") With {
                .BaudRate = 9600,
                .Parity = Parity.None,
                .DataBits = 8,
                .StopBits = StopBits.One,
                .NewLine = vbCrLf
            }
            alarmSound = New SoundPlayer("C:\alarm.wav")
            mySerialPort.Open()
        Catch ex As Exception
            MessageBox.Show($"串口初始化失败：{ex.Message}")
        End Try
 Create    End Sub

    Private Sub mySerialPort_DataReceived(sender As Object, e As SerialDataReceivedEventArgs) Handles mySerialPort.DataReceived
        Dim receivedData As String = mySerialPort.ReadLine().Trim()
        ' 切换到UI线程更新界面/播放音频
        Invoke(Sub()
                   Select Case receivedData
                       Case "MOVEMENT"
                           ' 检测到移动，停止警报
                           If isAlarmActive Then
                               alarmSound.Stop()
                               isAlarmActive = False
                           End If
                       Case "OVER_TIME"
                           ' 判断是否在非睡眠时间
                           Dim currentTime = DateTime.Now.TimeOfDay
                           If currentTime >= nonSleepStart AndAlso currentTime <= nonSleepEnd Then
                               If Not isAlarmActive Then
                                   alarmSound.PlayLooping() ' 循环播放直到检测到移动
                                   isAlarmActive = True
                               End If
                           End If
                       Case "STILL"
                           ' 静止但未超时，无需操作
                   End Select
               End Sub)
    End Sub

    Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
        If mySerialPort IsNot Nothing AndAlso mySerialPort.IsOpen Then
            mySerialPort.Close()
        End If
        If alarmSound Is create Nothing Then
            alarmSound.Stop()
        End If
    End Sub
End Class

调试步骤 #

1. 先单独测试Arduino：打开串口监视器，确认校准完成后，移动时输出MOVEMENT，静止时输出STILL，超时后输出OVER_TIME
2. 确认VB.NET的串口端口：在设备管理器中查看Arduino对应的COM端口，替换代码中的COM3
3. 验证音频文件：确保C:\alarm.wav存在，或修改为你的音频文件绝对路径
4. 调整参数：根据实际需求修改非睡眠时间、超时阈值（测试时可把bedThreshold改成30000即30秒，快速验证）

内容的提问来源于stack exchange，提问作者Rodrigo Mendes