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index 8c6e80b..378569b 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -34,9 +34,21 @@
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@@ -119,7 +131,7 @@
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@@ -170,10 +182,11 @@
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diff --git a/04. Programming/QT/timer.md b/04. Programming/QT/timer.md
new file mode 100644
index 0000000..44614b5
--- /dev/null
+++ b/04. Programming/QT/timer.md	
@@ -0,0 +1,19 @@
+使用QTimer來反覆執行工作。
+QTimer可以單次執行，也可以多次執行。
+
+使用概念如下：
+1. 建立 QTimer 物件，例如叫做 timer。
+2. 連接QTimer的timeout signal到你的反應 function
+3. 呼叫 timer->start()
+
+Example:
+```cpp
+QTimer* timer = new QTimer(this);
+connect(timer, SIGNAL(timeout()), this, SLOT(update()));
+timer->start(1000);
+```
+
+QTimer可以單次執行：
+```cpp
+QTimer::singleShot(200, this, SLOT(update());
+```