Python 3 code Question

Question

Hi. I am new to the Raspberry Pi. I have a Raspberry Pi 3 and a PiFace 2. I am trying to update a Christmas decoration made over 40 years ago by my father. It was run by a rotisserie motor and a wooden cylinder with copper strips and screws to make contact and light the stars up in sequences.

I have 5 stars in the following formation:

1 2

5

4 3

I am trying to have the stars light up in a certain sequence with a small delay in between each function

1

2

3

4

5

1,2,3

2,3,4

3,4,1

4,1,2

1,2,5

2,3,5

3,4,5

4,5,1

1,2,3,4,5

then begin the sequence again.

I have tried following as many of the posts as I can and receive errors on everything from syntax to int and tuples.

I am sure that it is something that is simple to the rest of you but just eludes me. Any help in any way will be greatly appreciated.

Elli

jdlui · Answer

Hi Ellen, Suggestion: With any problem I think it's helpful try and break things into pieces. Share more info with us on what you've tried, what isn't working, what code you are using. I.E. Have you tested a basic python script to get PiFace to turn on a single light yet? Confirm that this is working before you proceed. Test it on a random light like an LED. Then test it on your ornament. Hardware - PiFace I've never worked with PiFace so I don't know what your hookup options are to your ornament. I assume you have already made your electrical connections? Completed to the point where you can turn on a light if you run some basic blink script? There seems to Code - The Loop What code have you tried so far? Share it and we can help you more easily. Here is an example code that will look through your lighting combinations. This will go through each lighting combination and wait 1 second in between. Try running it and see how it works. You can modify the wait time as well. Hope this helps! J import time
# Example of a script to cycle through and change light sequence

# Every lighting combination can be summarized as a '1' for an on light and an '0' for an off light.
# Those combinations are shown below.
lights = ['10000','01000','00100','00010','00001','11100','01110','10110','11010','11001','01101','00111','10011','11111']

# Define wait time for our function
waittime = 1 # Number of seconds between light sequences, measured in seconds.

# We want this script to run perpetually so we create a while True loop
while True:
 # We iterate through each item in our list of light combinations, which is called 'lights'
 for index,item in enumerate(lights):
 # Putting a bunch of text print outs so you can see how the loop iterates
 print('We are now printing combination number',index+1,'in our light sequence')
 print('Light combination is',item)

# Here is where you would send the data to the PiFace to control its lighting.
 print('If we send these commands to a lighting system 
light 1 is',item[0],'light 2 is',item[1],'light 3 is',item[2],'light 4 is',item[3],'light 5 is',item[4],'
')
 # Insert some lighting command here. Use the on/off data stored in the item variable to turn your lights on or off.

# Now we use time command to put a delay in between lighting instruction
 time.sleep(waittime)
 print('Completed all sequences. repeating')

urkraft · Answer

To Douglas Wong: Sorry, i see now that your post was not directed to me. Was not very focused when i read it. I did notice that there was a very important bug in my code in that it did not handle interrupts and could easily enter an undesirable state when stopped. A better solution to my submission follows: #!/usr/bin/env python3 import pifacedigitalio, time, sys pfd = pifacedigitalio.PiFaceDigital() try: while True: pfd.output_port.value = 0x02 time.sleep(0.5) pfd.output_port.value = 0x04 time.sleep(0.5) pfd.output_port.value = 0x08 time.sleep(0.5) pfd.output_port.value = 0x10 time.sleep(0.5) pfd.output_port.value = 0x20 time.sleep(0.5) pfd.output_port.value = 0x0E time.sleep(0.5) pfd.output_port.value = 0x1C time.sleep(0.5) pfd.output_port.value = 0x1A time.sleep(0.5) pfd.output_port.value = 0x16 time.sleep(0.5) pfd.output_port.value = 0x26 time.sleep(0.5) pfd.output_port.value = 0x2C time.sleep(0.5) pfd.output_port.value = 0x38 time.sleep(0.5) pfd.output_port.value = 0x32 time.sleep(0.5) pfd.output_port.value = 0x3E time.sleep(0.5) except: pfd.output_port.all_off() pfd.deinit_board() print('
Exiting due to unexpected interrupt.') sys.exit(0)

urkraft · Answer

Since there is a lot of unnecessary repetition and generally bad programming practices in my previous posts on this topic, i have cleaned up my code a bit. This is my alternative solution: #!/usr/bin/env python3 import pifacedigitalio, time, sys pause_time = 0.5 the_sequence = [ 0x02, 0x04, 0x08, 0x10, 0x20, 0x0E, 0x1C, 0x1A, 0x16, 0x26, 0x2C, 0x38, 0x32, 0x3E] pfd = pifacedigitalio.PiFaceDigital() try: while True: for seq in the_sequence: pfd.output_port.value = seq time.sleep(pause_time) except: pfd.output_port.all_off() pfd.deinit_board() print('
Exiting due to unexpected interrupt.') sys.exit(0)

Python 3 code Question

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