DotStar Pi Painter HELP !

[ludwig_pop]

Hi everyone,
I'm french photographer. I started this project : https://learn.adafruit.com/dotstar-pi-p ... y-pi-setup
I follow all steps to set-up the raspberry (raspberry pi 2 + raspberry Pi OS Lite 32).

But after doing: pyhton 3 DotStarPiPainter.py

I have an error message:
python3: can't open file '/home/lightpainting/DotStarPiPainter.py': [errno2] no such file or directory.

Can you help me?
Merci beaucoup :)

[mikeysklar]

Can you try typing the following from where you had run the python command?

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pwd
ls *.py

The command you had used to launch the program has typos, but if I can see the full path I might should be able to correct it for you.

[ludwig_pop]

Thank you for your reply.
I typed your instructions.

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pwd

The console displays :
/home/lightpainting

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ls *.py

The console displays :
ls: cannot access '*.py' : No such fileor directory

I've joined a screenshot at this post.

[mikeysklar]

Thank you.

It looks like there is no code there. At least not a python script.

Based on the guide instructions you should have the script here.

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cd DotStarPiPainter
python3 DotStarPiPainter.py

If all goes well, nothing should happen…it’s waiting for a USB drive to be inserted. Plug in a USB flash drive with one or more images on it, and after a moment you should see it print a message that it’s loading and processing an image. Fantastic! Press Control+C to break out of the program and we’ll do some final setup.

Were you able to follow all the steps on this guide page? There are several components to install.

[ludwig_pop]

Thank you for your help. I have entered your orders. I can run the python script fine. Unfortunately, I have an error. :(

Traceback (most recent call last):
File "/DotStarPiPainter.py", Line 48, in <module>
from lightpaint import LightPaint
ImportError: /home/lightpainting/DotStarPiPainter/lightpaint.so: undefined symbol: __pow_finite

I finded an post on this forum where this problem is mentioned : viewtopic.php?t=185938&start=15
------
For what it's worth, thought I'd report back on some findings.

Application was failing using RPi Lite (32 bit) 10/30/21 release.
Application runs using RPi Lite (Legacy) 2/12/21 release.

Not sure why, but no errors.

Problem I'm still working on its that the app recognizes my usb drive when I plug it in, but finds zero files (I added some code to spit out how many).
------

If i understand, I have a problem with my OS version ! I will try to reinstall my raspberry whith RPi Lite (Legacy) : https://www.raspberrypi.com/software/operating-systems/

I will share my experience on this post.

[mikeysklar]

Good find, but that forum thread you linked to is a 2 year old post so the Legacy Rpi Lite build 2/12/21 release has been replaced with a newer Legacy Lite 3/5/23.

Lets start with what version of Pi OS do you currently have installed? Please share the output from this command.

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cat /etc/os-release

As the guide you have been following indicates you need to recompile the library.

thread you linked to is a 2 year old post so the Legacy Rpi Lite build 2/12/21 release has been replaced with a newer Legacy Lite 3/5/23. The current legacy build may work for you so please give it a try.

I went ahead and built it on my Pi4 running Bullseye. You can let me know if it works for you.

FWIW, I did have to remove some hard coding in the source.

* lightpaint.c - change from including python3.5 to any python release.

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#include <Python.h>

* Makefile - added compiler flags to include python3.9 folder

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CFLAGS = -fPIC -Ofast -fomit-frame-pointer -funroll-loops -I/usr/include/python3.9

I've attached the library and modified files for you to try with your current Pi OS install.

DotStarPiPainter-updated.zip

(82.38 KiB) Downloaded 109 times

[mikeysklar]

I opened and issue with the DotStarPiPainter github repo about the source code needing to be rebuilt for Pi OS Bullseye and the suggested source changes (style).

[ludwig_pop]

Thank you for help !
I lanch this code :

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cat /etc/os-release

My raspberry show :

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pi@raspberrypi:~ $ cat /etc/os-releasepi@raspberrypi:~ $ cat /etc/os-release
PRETTY_NAME="Raspbian GNU/Linux 11 (bullseye)"
NAME="Raspbian GNU/Linux"
VERSION_ID="11"
VERSION="11 (bullseye)"
VERSION_CODENAME=bullseye
ID=raspbian
ID_LIKE=debian
HOME_URL="http://www.raspbian.org/"
SUPPORT_URL="http://www.raspbian.org/RaspbianForums"
BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs"

[ludwig_pop]

Then, i apply your modifications in lightpaint.c et Makefile.

lightpaint.c - i replace

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#include <python3.5/Python.h>

by

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#include <Python.h>

Makefile - i replace

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CFLAGS = -fPIC -Ofast -fomit-frame-pointer -funroll-loops

by

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CFLAGS = -fPIC -Ofast -fomit-frame-pointer -funroll-loops -I/usr/include/python3.9

Unfortunately, i have the same error when i launch DotStarPiPainter.py :

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pi@raspberrypi:~/DotStarPiPainter $ python3 DotStarPiPainter.py
Traceback (most recent call last):
  File "/home/pi/DotStarPiPainter/DotStarPiPainter.py", line 48, in <module>
    from lightpaint import LightPaint
ImportError: /home/pi/DotStarPiPainter/lightpaint.so: undefined symbol: __pow_finite

[mikeysklar]

You made the correct changes, but you need to run the ‘make’ command (just once) before running the python script.

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make

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python3 DotStarPiPainter.py

[ludwig_pop]

Awesome ! The script works :) Thanks

But nothing happens when I plug in the USB stick.
99_lightpaint_mount and 99_lightpaint_umount are in the good directory.
But, i've not finded "MountFlags=slave" on the system file => /lib/systemd/system/systemd-udevd.service

[mikeysklar]

Show me that the mount / umount files are in the correct location. Your previous screen shot showed them in your home directory, but they need to be under the respective /etc/usbmount folders as the instructions show:

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cd DotStarPiPainter
sudo cp 99_lightpaint_mount /etc/usbmount/mount.d
sudo cp 99_lightpaint_umount /etc/usbmount/umount.d

Run these commands to show me they are there:

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ls /etc/usbmount/mount.d 
ls /etc/usbmount/umount.d

Did you modify the system-udevd.service file? Let's see the content.

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cat /lib/systemd/system/systemd-udevd.service

[ludwig_pop]

I did the instructions :

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cd DotStarPiPainter
sudo cp 99_lightpaint_mount /etc/usbmount/mount.d
sudo cp 99_lightpaint_umount /etc/usbmount/umount.d

I verify if files are in the correct location.
My raspberry shows :

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pi@raspberrypi:~/DotStarPiPainter $ ls /etc/usbmount/mount.d
00_create_model_symlink  99_lightpaint_mount
pi@raspberrypi:~/DotStarPiPainter $ ls /etc/usbmount/umount.d
00_remove_model_symlink  99_lightpaint_umount
pi@raspberrypi:~/DotStarPiPainter $ 

I don't modify : /lib/systemd/system/systemd-udevd.service

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pi@raspberrypi:~/DotStarPiPainter $ cat /lib/systemd/system/systemd-udevd.service
#  SPDX-License-Identifier: LGPL-2.1-or-later
#
#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

[Unit]
Description=Rule-based Manager for Device Events and Files
Documentation=man:systemd-udevd.service(8) man:udev(7)
DefaultDependencies=no
After=systemd-sysusers.service systemd-hwdb-update.service
Before=sysinit.target
ConditionPathIsReadWrite=/sys

[Service]
DeviceAllow=block-* rwm
DeviceAllow=char-* rwm
Type=notify
# Note that udev will reset the value internally for its workers
OOMScoreAdjust=-1000
Sockets=systemd-udevd-control.socket systemd-udevd-kernel.socket
Restart=always
RestartSec=0
ExecStart=/lib/systemd/systemd-udevd
ExecReload=udevadm control --reload --timeout 0
KillMode=mixed
TasksMax=infinity
PrivateMounts=yes
ProtectClock=yes
ProtectHostname=yes
MemoryDenyWriteExecute=yes
RestrictAddressFamilies=AF_UNIX AF_NETLINK AF_INET AF_INET6
RestrictRealtime=yes
RestrictSUIDSGID=yes
LockPersonality=yes
IPAddressDeny=any
WatchdogSec=3min

Un grand merci !

[mikeysklar]

It looks like you found another issue with the guide related to a Pi OS update.

Starting with Pi OS Buster the syntax has changed for getting usbmount to work.

Try the following.

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sudo nano /lib/systemd/system/systemd-udevd.service

In the [Service] section of the configuration file add this line:

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PrivateMounts=no

restart udevd:

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sudo systemctl restart systemd-udevd

Now is your USB drive detected on insertion?

[ludwig_pop]

All works fine ! The script read only usb key fomated on FAT32.
Merci.