diff --git a/src/main.cpp b/src/main.cpp
index b64f693..9398aa3 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -281,7 +281,27 @@ void loop()
 }
 
 void on_pin_change(uint8_t pin, uint8_t value)
-{}
+{
+  // For input pin 0-3, map it with output pin 0-3
+  // For input pin 4-7, map it with output pin 8-11
+  // For input pin 12, map it with output pin 12
+  // When Input pin change, Toggle the output pin
+  if (pin < 4)
+  {
+    bool new_value = !espmega.outputs.getState(pin);
+    espmega.outputs.setState(pin, new_value);
+  } 
+  else if (pin < 8)
+  {
+    bool new_value = !espmega.outputs.getState(pin + 4);
+    espmega.outputs.setState(pin + 4, new_value);
+  }
+  else if (pin == 12)
+  {
+    bool new_value = !espmega.outputs.getState(12);
+    espmega.outputs.setState(12, new_value);
+  }
+}
 
 uint16_t get_pm25_out()
 {