diff --git a/ES/Lab/Lab11/PWM_Keyboard.c b/ES/Lab/Lab11/PWM_Keyboard.c
index e1e2325..b0cb2e0 100644
--- a/ES/Lab/Lab11/PWM_Keyboard.c
+++ b/ES/Lab/Lab11/PWM_Keyboard.c
@@ -1,33 +1,22 @@
 #include "LPC17xx.h"
+#include <stdio.h>
 
 unsigned long int duty_cycle = 0;
-int direction = 1;
-int step = 50;
+unsigned long int new_duty = 0;
+int press_count = 0;
+
+void delayMs(unsigned int ms)
+{
+    unsigned int i, j;
+    for (i = 0; i < ms; i++)
+        for (j = 0; j < 20000; j++);
+}
 
 void PWM1_IRQHandler(void)
 {
     if (LPC_PWM1->IR & (1 << 0))
     {
-        if (direction == 1)
-        {
-            duty_cycle += step;
-            if (duty_cycle >= 3000)
-            {
-                duty_cycle = 3000;
-                direction = 0;
-            }
-        }
-        else
-        {
-            duty_cycle -= step;
-            if (duty_cycle <= 0)
-            {
-                duty_cycle = 0;
-                direction = 1;
-            }
-        }
-
-        LPC_PWM1->MR4 = duty_cycle;
+        LPC_PWM1->MR4 = new_duty;
         LPC_PWM1->LER = (1 << 4);
         LPC_PWM1->IR = (1 << 0);
     }
@@ -35,23 +24,47 @@ void PWM1_IRQHandler(void)
 
 int main(void)
 {
+    char key;
+
     LPC_PINCON->PINSEL3 |= (2 << 14);
-
     LPC_PWM1->TCR = (1 << 1);
-    LPC_PWM1->CTCR = 0;
+    LPC_PWM1->CTCR = 0x00;
     LPC_PWM1->PR = 0;
-
     LPC_PWM1->MR0 = 3000;
     LPC_PWM1->MR4 = duty_cycle;
-
     LPC_PWM1->MCR = (1 << 1) | (1 << 0);
     LPC_PWM1->PCR = (1 << 12);
-
     LPC_PWM1->LER = (1 << 0) | (1 << 4);
 
     NVIC_EnableIRQ(PWM1_IRQn);
 
     LPC_PWM1->TCR = (1 << 0) | (1 << 3);
 
-    while (1);
+    printf("Press any key to change brightness...\n");
+
+    while (1)
+    {
+        key = getchar();
+
+        if (key)
+        {
+            press_count++;
+
+            if (press_count == 1)
+                new_duty = 300;
+            else if (press_count == 2)
+                new_duty = 1500;
+            else if (press_count == 3)
+                new_duty = 2700;
+            else
+            {
+                new_duty = 0;
+                press_count = 0;
+            }
+
+            printf("Duty cycle set to %lu\r\n", new_duty);
+
+            delayMs(500);
+        }
+    }
 }