[Tutor] Help needed

Joel Goldstick joel.goldstick at gmail.com
Thu Feb 4 19:13:19 EST 2016

On Thu, Feb 4, 2016 at 6:26 PM, Tom Brodle <tbrodle at hotmail.com> wrote:

> I am very new  to Python.  I am just practicing code using a simple plug
> board.  The code is working as I want it to but the last message and the
> original looping makes me have questions.  Because the main code works I
> will just abbreviate it.
> import GPIO
> import time
> Gpio setmode (BCM)
> led_pin = 18
> GPIO setup(led_pin, GPIO)
> try:
>         While true:

Actually you need:
            While True:

This means run forever.  In the while loop you need some test to break or
this loop will run forever.  You can press Ctl-C to quit the program

>             Turn LED on
>             sleep 5 seconds
>             Turn LED off
>             sleep .5 seconds  # program was initially designed to keep LED
> turning on and off and that worked.
>                                            # Coming from the world of
> Basic I did/do not understand what made the program loop
>                                            # back to while True: line of
> code.
>                                            # I  wanted the LED to turn on
> and then off and stay off, so from some Python.org
>                                            # page I became aware of
> quit(code=None) and inserted it before the line Print("Cleaning up")
>           quit(code=None)            # I put this line in to stop the
> looping back to While true:.
>     Print("Cleaning up")
>     GPIO.cleanup()           # I was told to put this line in but I do not
> know where it goes to do whatever.
>                                           #The code did turn the LED on
> once and then it did stay off, but it gave me a message that
>                                           # the  program is still
> running.  I did not think that programs actually did stop until the
>                                           # power was removed.
> Thanks
> Tom
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Joel Goldstick

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