Raspberry Pi 4 LED output

''' rp_output_test104.py

Turn 4 different LEDs on and off

The black terminal strip is located on the upper side of the Raspberry B+ board
there a two rows of 20 physical pins each
the upper row starts with the even pins 2 (upper left corner, ulc) to 40
the lower row starts with the odd pins 1 (lower left corner, llc) to 39

We will be using the following pins:
GND (pin 9)
GPIO17 (pin 11)
GPIO27 (pin 13)
GPIO22 (pin 15)
GPIO23 (pin 16)
17, 22, 23, 27 are the internal Broadcom (BCM) numbers

These might be the LED colors red, yellow, blue, green

Each of the LEDs is in series with a 220 ohm current limiting resistor
connect the LED cathode (has flat spot, shorter lead) toward GND and
the free end of the resistor to the proper GPIO
GPIO HIGH will be about +3 volt (each LED draws about 5 mA)
GPIO LOW will be 0 volt

220 ohm --> red(2) red(2) brown(1) gold(5%) bands
(you can use a 200 to 500 ohm resistor to limit the current)

Note:
each GPIO is limited to no more than 15mA current draw
the sum of all currents flowing through GPIOs is limited to 50mA

To execute this code from the idle IDE start idle as root (super user)
via terminal command:  sudo idle

To run from the LXTerminal -->
(assume that the code is in directory rpi_python)
cd rpi_python
sudo python rp_output_test104.py

tested with a Raspberry PI B+, Linux/Rasbian OS, Python27

picture at: prntscr.com/5kbm3s
code stored at:

for parts used see ...
http://www.canakit.com/raspberry-pi-starter-ultimate-kit.html
'''

import RPi.GPIO as gpio
import time

def output_on(nn):
    # GPIOnn will go to +3.3 volt
    # you can use gpio.HIGH, True, or 1
    gpio.output(nn, gpio.HIGH)

def output_off(nn):
    # GPIOnn goes to 0 volt
    # you can use gpio.LOW, False, or 0
    gpio.output(nn, gpio.LOW)


def output_blink(nn, blinks, delay=1):
    for k in range(blinks):
        print("Blink {}".format(k+1))
        output_on(nn)
        time.sleep(delay)
        output_off(nn)
        time.sleep(delay)

# use Broadcom GPIO 00..nn numbers (recommended)
gpio.setmode(gpio.BCM)

led_list = ['red', 'yellow', 'blue', 'green']
# these are the BCM GPIO numbers we are using
# the red LED is connected to GPIO17 and so on
gpio_list = [17, 22, 23, 27]
# set them all to output
for nn in gpio_list:
    gpio.setup(nn, gpio.OUT)

delay = 3
for color, nn in enumerate(gpio_list):
    sf = "LED {} on for {} seconds ..."
    print(sf.format(led_list[color], delay))
    output_on(nn)
    # keep LED on for delay seconds
    time.sleep(delay)
    output_off(nn)
    # wait 1 second
    time.sleep(1)


# let's do some blinking
nn = 17
blinks = 5
delay = 0.5
sf = "LED {} blinking {} times with {} second delay"
for color, nn in enumerate(gpio_list):
    print(sf.format(led_list[color], blinks, delay))
    output_blink(nn, blinks, delay)

print("Real quick action ...")
for k in range(20):
    for nn in gpio_list:
        output_on(nn)
        time.sleep(0.1)
        output_off(nn)
        time.sleep(0.05)

print("Turn all LEDs on for 1 minute ...")
for nn in gpio_list:
    output_on(nn)

time.sleep(60)

# reset all GPIO channels used by this program
gpio.cleanup()

#help(gpio)