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--- gpio_inputs_-_button_led_control [2016/08/09 20:14] – walkeradmin
+++ gpio_inputs_-_button_led_control [2017/10/22 15:38] (current) – [The Button in Action] walkeradmin
@@ Line 32: / Line 32: @@
     sudo nano LED-Button.py
 \\
+** You can download the code {{ :led-button.zip |Here}}: **
 \\
-#import modules
+    #import modules
-import RPi.GPIO as GPIO    # This imports the GPIO libarary that allows the use of the GPIO pins,
+    import RPi.GPIO as GPIO    # This imports the GPIO libarary that allows the use of the GPIO pins,
-                           # These libraries are built in to Raspbian.
+                               # These libraries are built in to Raspbian.
-GPIO.setmode (GPIO.BOARD)  # This sets the GPIO pin numbering. Our LED is connected to Pin 12,
+    GPIO.setmode (GPIO.BOARD)  # This sets the GPIO pin numbering. Our LED is connected to Pin 12,
-                           # so we can reference it by using BOARD as pin 12. However there is
+                               # so we can reference it by using BOARD as pin 12. However there is
-                           # another option (BCM) where we can reference a pin by it's name, pin
+                               # another option (BCM) where we can reference a pin by it's name, pin
-                           # 12 is called GPIO18 (a reference to its place on the chip).
+                               # 12 is called GPIO18 (a reference to its place on the chip).
-GPIO.setup(11, GPIO.IN, pull_up_down=GPIO.PUD_DOWN) # setup GPIO Pin 11 as an input, and set
+    GPIO.setup(11, GPIO.IN, pull_up_down=GPIO.PUD_DOWN) # setup GPIO Pin 11 as an input, and set
-                                                    # the resistor to Pull Down (PUD_DOWN)
+                                                        # the resistor to Pull Down (PUD_DOWN)
-                                                    # this is the pin the button is connected to
+                                                        # this is the pin the button is connected to
-                                                    # button is connected from pin 11 to the
+                                                        # button is connected from pin 11 to the
-                                                    # +3.3v pin on the GPIO
+                                                        # +3.3v pin on the GPIO
-GPIO.setup(12, GPIO.OUT)   # Sets the GPIO pin as output. This is connected to the LED, then
+    GPIO.setup(12, GPIO.OUT)   # Sets the GPIO pin as output. This is connected to the LED, then
-                           # from the LED to 0v via a 330 Ohm resistor.
+                               # from the LED to 0v via a 330 Ohm resistor.
-GPIO.output(12, 0)         # sets the GPIO Pin 12 to low (so 0v)
+    GPIO.output(12, 0)         # sets the GPIO Pin 12 to low (so 0v)
-try:
+    try:
-        while True:                             # start a loop
+            while True:                             # start a loop
-                if (GPIO.input(11) == 0):       # if GPIO pin 11 is a 0 (Low (0v)) then..
+                    if (GPIO.input(11) == 0):       # if GPIO pin 11 is a 0 (Low (0v)) then..
-                        GPIO.output(12,0)       # set Pin 12 to 0v (LED Stays off)
+                            GPIO.output(12,0)       # set Pin 12 to 0v (LED Stays off)
-                else:                           # if GPIO pin is anything other than High (3.3v) then..
+                    else:                           # if GPIO pin is anything other than High (3.3v) then..
-                        GPIO.output(12,1)       # set Pin 12 to 3.3v (LED comes on)
+                            GPIO.output(12,1)       # set Pin 12 to 3.3v (LED comes on)
-except KeyboardInterrupt:                       # if Ctrl-C is pressed, exit loop
+    except KeyboardInterrupt:                       # if Ctrl-C is pressed, exit loop
-        GPIO.cleanup()                          # reset GPIO pins to default state
+            GPIO.cleanup()                          # reset GPIO pins to default state
-#End
+    #End
+\\
+\\
+==== The Button in Action ====
+Here is the button turning on the LED {{:led-button.mp4|950x574|autoplay,loop}}
+\\
+\\
+==== A Small Issue ====
+\\
+While this code works without any real problems, because we are in a constant loop, this code is very heavy on CPU load, on the Pi Zero I am using this causes the processer to sit at 100 %, a better method is to use an **interrupt**
+\\
+\\
+This guide is comprised of information from a youtube video by **Gaven MacDonald**. Thanks Gaven.
+\\
+\\