diff --git a/CommandHandler.cs b/CommandHandler.cs
index 31bf630..584bb07 100644
--- a/CommandHandler.cs
+++ b/CommandHandler.cs
@@ -14,7 +14,8 @@ namespace DualScreenDemo
     public class CommandHandler
     {
         public static bool readyForSongListInput = false;
-
+        private readonly int _maxHistoryLength = 6; // 最多保留 6 筆
+        private readonly Queue<string> _indataHistory = new Queue<string>();
         private readonly SongListManager songListManager;
 
         public CommandHandler(SongListManager songListManager)
@@ -25,13 +26,7 @@ namespace DualScreenDemo
         //關機錨點
         public async Task ProcessData(string indata)
         {
-            string filePath = Path.Combine(Application.StartupPath, "dataLog.txt");
-            if (CheckLogForShutdown(filePath))
-            {
-                Console.WriteLine("Shutdown condition met. Application will now close.");
-                ShutdownComputer();
-            }
-
+            AddToHistory(indata);
             switch (indata)
             {
                 case "A261A4":
@@ -188,6 +183,29 @@ namespace DualScreenDemo
             }
         }
 
+        private void AddToHistory(string indata)
+        {
+            if (_indataHistory.Count >= _maxHistoryLength)
+            {
+                _indataHistory.Dequeue(); // 移除最舊的項目
+            }
+            _indataHistory.Enqueue(indata); // 添加新的項目
+            CheckSequenceforClose(); // 每次更新完 queue 後檢查
+        }
+        private void CheckSequenceforClose()
+        {
+            string[] targetSequence = { "A262A4", "A262A4", "A262A4", "A261A4", "A261A4", "A261A4" };
+
+            if (_indataHistory.Count == targetSequence.Length &&
+                _indataHistory.SequenceEqual(targetSequence))
+            {
+                // 👇 這裡就是條件符合時要做的事情
+                Console.WriteLine("Shutdown condition met. Application will now close.");
+                ShutdownComputer();
+                // 你可以呼叫其他方法、觸發事件、改狀態等等
+            }
+        }
+
         void InvokeAction(Action action)
         {
             if (OverlayForm.MainForm.InvokeRequired)
@@ -895,20 +913,6 @@ private static void DisplaySongHistory()
             }
         }
 
-        public static bool CheckLogForShutdown(string filePath)
-        {
-            if (File.Exists(filePath))
-            {
-                
-                string content = File.ReadAllText(filePath).Replace(Environment.NewLine, "");
-                if (content.Length >= 6 && content.Substring(content.Length - 6) == "bbbaaa")
-                {
-                    return true;
-                }
-            }
-            return false;
-        }
-
         public static void ShutdownComputer()
         {
             try