====== BreathingLED ======

**//The Circuit://**
{{:hpc0:breathingled.jpg?nolink|}}

**//The Code: //**
<code py>
  1 #!/usr/bin/env python3                                           
  2 ########################################################################
  3 # Filename    : BreathingLED.py                                  
  4 # Description : Breathing LED                                    
  5 # Author      : www.freenove.com                                 
  6 # modification: 2019/12/27                                       
  7 ########################################################################
  8 import RPi.GPIO as GPIO                                          
  9 import time                                                      
 10                                                                  
 11 LedPin = 12                           # define the LedPin        
 12                                                                  
 13 def setup():                                                     
 14     global p                                                     
 15     GPIO.setmode(GPIO.BOARD)          # use PHYSICAL GPIO Numbering
 16     GPIO.setup(LedPin, GPIO.OUT)      # set LedPin to OUTPUT mode
 17     GPIO.output(LedPin, GPIO.LOW)     # make ledPin output LOW level to turn off LED 
 18                                                                  
 19     p = GPIO.PWM(LedPin, 500)         # set PWM Frequence to 500Hz
 20     p.start(0)                        # set initial Duty Cycle to 0
 21                                                                  
 22 #Function that handles the brightness of the LED                 
 23 def loop():                                                      
 24     while True:                                                  
 25         #While in brightness  ranges of 0 - 100 get brighter. Stop at 100
 26         for dc in range(0, 101, 1):                              
 27             p.ChangeDutyCycle(dc)     # set dc value as the duty cycle
 28             time.sleep(0.01)                                     
 29         #after hitting max birghtness wait 1 second              
 30         time.sleep(1)                                            
 31         #after hitting max brightness darken the LED till it is off
 32         for dc in range(100, -1, -1):                            
 33             p.ChangeDutyCycle(dc)     # set dc value as the duty cycle
 34             time.sleep(0.01)                                     
 35         #when the LED is off wait one second before starting over
 36         time.sleep(1)                                            
 37                                                                  
 38 #function that will end the program                              
 39 def destroy():                                                   
 40     p.stop()                          # stop PWM                 
 41     GPIO.cleanup()                    # Release all GPIO         
 42                                                                  
 43 if __name__ == '__main__':                                       
 44     print ('Program is starting ... ')                           
 45     setup()                                                      
 46     try:                                                         
 47         loop()                                                   
 48     except KeyboardInterrupt:         # When program ends cleanup                                           
 49         destroy()
</code>

In this project the LED will gradually get brighter and brighter till it hits max brightness. Then it will grow darker and darker till the LED is turned off. This was a simple setup only requiring a resistor, LED, and two jumpers. Otherwise I went through the code making the comments look neater and explaining the functions.