描述

該項目是一個基于 Arduino 的警報，用于監控計算機是否正常工作。萬一電腦死機，它會發出警告聲信號。

該項目由兩部分組成：在計算機上運行的程序和連接在 USB 端口中的 Arduino。

計算機程序以 1 秒的間隔向 Arduino 發送一個預定義的字符。Arduino 從計算機發送的數據中讀取數據。如果它在 10 秒內沒有收到任何字符，它會從連接到引腳 10 的蜂鳴器發出聲音。

計算機程序是用 Visual Basic 編寫的。它是一個簡單的 Windows 窗體應用程序，包含一個窗體 (Form1)、一個標簽 (Label1) 和一個計時器 (Timer1)。

Timer1 間隔設置為 1000 ms。

計算機程序的源代碼：

Imports System.IO.Ports
Public Class Form1
   Dim port As SerialPort
   Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
       port = New SerialPort("COM4", 9600) 'Set your board COM
       port.Open()
   End Sub
   Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
       port.Close()
   End Sub
   Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
       On Error GoTo error1
       port.Write("1") 'character to send to COM port, wich the Arduino will expect.
       Label1.Text = Now() & " - Sent ""1"" on COM4 baud 9600 - Success!"
       Exit Sub
error1:
       Label1.Text = Now() & " - " & ErrorToString()
   End Sub
End Class

Arduino程序源代碼：

char incomingChar = 0; // for incoming serial data
int NoSignalCounter = -60; // delay to allow for computer startup time
void setup() {
 Serial.begin(9600); // opens serial port, sets data rate to 9600 bps
}
void loop() {
 while (Serial.available() > 0) {
   NoSignalCounter = 0;
   incomingChar = Serial.read();
   if (incomingChar == '1') { // '1' is the character expected from the computer
     noTone(10);
   }
   else {
     tone(10, 2400); // alarm: the character sent from the computer is different from the expected character
   }
 }
 NoSignalCounter++;
 if (NoSignalCounter >= 10) { // alarm: no character was received from the computer in the last 10 seconds
   NoSignalCounter = 0;
   tone(10, 2400); //(pin,frequency)
 }
 delay(1000);
}

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