diff --git a/.settings/org.eclipse.core.resources.prefs b/.settings/org.eclipse.core.resources.prefs
index 755ea81..718cb40 100644
--- a/.settings/org.eclipse.core.resources.prefs
+++ b/.settings/org.eclipse.core.resources.prefs
@@ -1,4 +1,6 @@
 eclipse.preferences.version=1
+encoding//Debug/docs/latex/subdir_rules.mk=UTF-8
+encoding//Debug/docs/latex/subdir_vars.mk=UTF-8
 encoding//Debug/driverlib/MSP430FR2xx_4xx/subdir_rules.mk=UTF-8
 encoding//Debug/driverlib/MSP430FR2xx_4xx/subdir_vars.mk=UTF-8
 encoding//Debug/jsmn/subdir_rules.mk=UTF-8
diff --git a/main.c b/main.c
index 4cffd0c..e86a47d 100755
--- a/main.c
+++ b/main.c
@@ -1,9 +1,6 @@
 /**
  * @file    main.c
- * @brief   UART console, interrupt-driven 4×4 keypad input, and Morse LED blink on MSP430FR2355.
- *
- * Initializes peripheral modules and enters low-power mode, waking on keypress
- * interrupts to blink Morse code on LED and echo keys over UART.
+ * @brief   Entrypoint for the program.
  *
  * @date    2025-07-02
  */
diff --git a/src/state_machine.c b/src/state_machine.c
index 5af30e3..108ec39 100644
--- a/src/state_machine.c
+++ b/src/state_machine.c
@@ -38,7 +38,7 @@
 #define BUZZER_PORT_DIR   P5DIR
 #define BUZZER_PORT_OUT   P5OUT
 #define BUZZER_PIN        BIT0
-#define BUZZER_PERIOD     1000U
+#define BUZZER_PERIOD     300U
 
 /** Red LED on P1.0. */
 #define LED_RED_PORT_DIR  P1DIR
@@ -87,6 +87,7 @@ char buffer_cd[17];
 /* Hardware feedback */
 static void update_leds(void);
 void buzz_invalid_input(void);
+void buzz_input(void);
 void sound_alarm(void);
 void reset_alarm(void);
 
@@ -233,10 +234,20 @@ void buzz_invalid_input(void)
 {
     /* beep 50ms */
     sound_alarm();
-    sleep(50);
+    sleep(400);
     reset_alarm();
 }
 
+/**
+ * @brief Short buzzer beep for invalid input.
+ */
+void buzz_input(void)
+{
+    /* beep 50ms */
+    sound_alarm();
+    sleep(50);
+    reset_alarm();
+}
 
 /**
  * @brief Sound the alarm continuously.
@@ -267,6 +278,8 @@ void reset_alarm(void)
  */
 static void keypad_handler(char key)
 {
+    buzz_input();
+
     keypad_last_key = key;
     keypad_flag_chg = true;
 
@@ -570,6 +583,7 @@ static void door_opened_handler(void)
 {
     if (!open_door_allowed()) {
         transition(STATE_UNAUTHORIZED);
+        sound_alarm();
     } else if (
         current_state != STATE_EDIT_STOCK_SELECT &&
         current_state != STATE_EDIT_STOCK_SET &&
@@ -603,6 +617,8 @@ static void door_closed_handler(void)
         transition(STATE_IDLE);
         door_open = false;
     }
+
+    reset_alarm();
 }