diff --git a/Code/Python_Code/06.2.1_Alertor/Alertor.py b/Code/Python_Code/06.2.1_Alertor/Alertor.py
index fe801d3..a329abd 100644
--- a/Code/Python_Code/06.2.1_Alertor/Alertor.py
+++ b/Code/Python_Code/06.2.1_Alertor/Alertor.py
@@ -41,6 +41,7 @@ def stopAlertor():
             
 def destroy():
     GPIO.output(buzzerPin, GPIO.LOW)     # Turn off buzzer
+    p.stop()  # stop PWM
     GPIO.cleanup()                       # Release GPIO resource
 
 if __name__ == '__main__':     # Program entrance
diff --git a/Code/Python_Code/08.1.1_Softlight/Softlight.py b/Code/Python_Code/08.1.1_Softlight/Softlight.py
index 2a753bf..ad3f4ea 100644
--- a/Code/Python_Code/08.1.1_Softlight/Softlight.py
+++ b/Code/Python_Code/08.1.1_Softlight/Softlight.py
@@ -38,6 +38,7 @@ def loop():
         time.sleep(0.03)
 
 def destroy():
+    p.stop()  # stop PWM
     GPIO.cleanup()
     adc.close()
     
diff --git a/Code/Python_Code/09.1.1_ColorfulSoftlight/ColorfulSoftlight.py b/Code/Python_Code/09.1.1_ColorfulSoftlight/ColorfulSoftlight.py
index d033603..58729ec 100644
--- a/Code/Python_Code/09.1.1_ColorfulSoftlight/ColorfulSoftlight.py
+++ b/Code/Python_Code/09.1.1_ColorfulSoftlight/ColorfulSoftlight.py
@@ -53,6 +53,9 @@ def loop():
 
 def destroy():
     adc.close()
+    p_Red.stop()  # stop PWM
+    p_Green.stop()  # stop PWM
+    p_Blue.stop()  # stop PWM
     GPIO.cleanup()
     
 if __name__ == '__main__': # Program entrance
diff --git a/Code/Python_Code/10.1.1_Nightlamp/Nightlamp.py b/Code/Python_Code/10.1.1_Nightlamp/Nightlamp.py
index 7d82006..55867f5 100644
--- a/Code/Python_Code/10.1.1_Nightlamp/Nightlamp.py
+++ b/Code/Python_Code/10.1.1_Nightlamp/Nightlamp.py
@@ -41,6 +41,7 @@ def loop():
 
 def destroy():
     adc.close()
+    p.stop()  # stop PWM
     GPIO.cleanup()
     
 if __name__ == '__main__':   # Program entrance
diff --git a/Code/Python_Code/13.1.1_Motor/Motor.py b/Code/Python_Code/13.1.1_Motor/Motor.py
index 8fef6c1..7343ea0 100644
--- a/Code/Python_Code/13.1.1_Motor/Motor.py
+++ b/Code/Python_Code/13.1.1_Motor/Motor.py
@@ -65,6 +65,7 @@ def loop():
         time.sleep(0.01)
 
 def destroy():
+    p.stop()  # stop PWM
     GPIO.cleanup()
     
 if __name__ == '__main__':  # Program entrance