BeagleBone - Onboard LED KnightRider by Shane B.

#Import Libraries
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#Tell python we need the library "os" for executing system commands directly
import os

#Tell python we need the library "time" so we can use the "sleep" command
import time

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#Define Variables
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#Define commands to be executed later on based on logic
#Command for turning led0 "On"
led0_on = 'echo 1 > /sys/class/leds/beaglebone::usr0/brightness'
#Command for turning led0 "Off"
led0_off = 'echo 0 > /sys/class/leds/beaglebone::usr0/brightness'


#Command for turning led1 "On"
led1_on = 'echo 1 > /sys/class/leds/beaglebone::usr1/brightness'
#Command for turning led1 "Off"
led1_off = 'echo 0 > /sys/class/leds/beaglebone::usr1/brightness'

#Command for turning led2 "On"
led2_on = 'echo 1 > /sys/class/leds/beaglebone::usr2/brightness'
#Command for turning led2 "Off"
led2_off = 'echo 0 > /sys/class/leds/beaglebone::usr2/brightness'

#Command for turning led3 "On"
led3_on = 'echo 1 > /sys/class/leds/beaglebone::usr3/brightness'
#Command for turning led3 "Off"
led3_off = 'echo 0 > /sys/class/leds/beaglebone::usr3/brightness'
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#Begin Execution
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#Infinite On/off loop to make light blink
#Define "i" variable
i = 0;

#Begin Infinite loop
while(True):
    if i == 0:
        #Tell Beaglebone that we want LED0 "on"
        os.system(led0_on)

        #Tell Beaglebone that we want LED0, LED1 and LED3 "off"
        os.system(led1_off)
        os.system(led2_off)
        os.system(led3_off)

        #Tell python to turn led1 on next
        i = 1

    elif i == 1:
        #Tell BeagleBone that we want LED1 "on
        os.system(led1_on)

        #Tell Beaglebone that we want LED0, LED2 and LED3 "off"
        os.system(led0_off)
        os.system(led2_off)
        os.system(led3_off)

        #Tell python to turn led2 on next
        i = 2

    elif i == 2:
        #Tell BeagleBone that we want LED2 "on
        os.system(led2_on)

        #Tell Beaglebone that we want LED0, LED1 and LED3 "off"
        os.system(led0_off)
        os.system(led1_off)
        os.system(led3_off)

        #Tell python to turn led3 on next
        i = 3

    elif i == 3:
        #Tell BeagleBone that we want LED3 "on
        os.system(led3_on)

        #Tell Beaglebone that we want LED0, LED1 and LED2 "off"
        os.system(led0_off)
        os.system(led1_off)
        os.system(led2_off)

        #Tell python to turn led0 on next
        i = 4

    elif i == 4:
        #Tell BeagleBone that we want LED2 "on
        os.system(led2_on)

        #Tell Beaglebone that we want LED0, LED1 and LED3 "off"
        os.system(led0_off)
        os.system(led1_off)
        os.system(led3_off)

        #Tell python to turn led0 on next
        i = 5

    elif i == 5:
        #Tell BeagleBone that we want LED1 "on
        os.system(led1_on)

        #Tell Beaglebone that we want LED0, LED2 and LED3 "off"
        os.system(led0_off)
        os.system(led2_off)
        os.system(led3_off)

        #Tell python to turn led0 on next
        i = 0

    #Tell python to pause for 1 second then after the 1 second is over then continue with the infinite while loop
    time.sleep(0.15)


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