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Pixy2: Python3 Linux

Pixy Software
#1

Hello,

I am a college student that will be using pixy cam for my project. My only problem is that I need Pixy2 to work with Python3 API. Just to start it, I installed libpixyusb2 and tried the CPP examples which worked. But when I tried doing the Python API and run it with ($ python3) and it’s giving me this error:

Input: $ python3 get_blocks_python_demo.py

Output:

  File "get_blocks_python_demo.py", line 2, in <module>
    import pixy
  File "/home/ubuntu/pixy2/build/python_demos/pixy.py", line 15, in <module>
    import _pixy
  ModuleNotFoundError: No module named '_pixy'

I already tried this forum: https://forum.pixycam.com/t/libpixyusb-python-module-trouble-python-3-related/6453/8
He basically said to change the Python —> Python3 in the bash file of build_python_demos.sh. But it didn’t work for me, the error is still the same as the top.

Please help…

#2

Hello,
You need to change your system python to point to python3. That is, for example:

pi@alpha:~/$ which python
/usr/bin/python
pi@alpha:~/$ ls -l /usr/bin/python
lrwxrwxrwx 1 root root 18 Jul 25 22:12 /usr/bin/python -> /usr/bin/python3.7

Here, the system python points to python3 (python3.7 specifically)
You may need to replace the link for python if it’s pointing to a python 2 version.

Once you get it pointing to the correct version, you can try to bulld.

Hope this helps.

Edward

#3

Hello,
Thank you so much for the quick reply. I apologize for not mentioning that I only have python3 installed on my system. Is it really possible to run the demo python script with python3?

I did what you told me but unfortunately it didnt work :

ubuntu@ubuntu:~$ which python
/usr/bin/python
ubuntu@ubuntu:~$ ls -l /usr/bin/python
lrwxrwxrwx 1 root root 7 Apr 15  2020 /usr/bin/python -> python3

Also when I try to run the build_python_demos.sh file, it gives me this error output:

image
image1586×848 48.3 KB

#4

Update: So I got it working by installing python3-dev to have an additional library and editing the file of build_python_demos.sh(python --> python3). But now the only problem I have is that when I run the file without sudo, I get this output:

ubuntu@ubuntu:~/pixy2/build/python_demos$ python3 get_blocks_python_demo.py
Pixy2 Python SWIG Example -- Get Blocks
Segmentation fault (core dumped)

However, w/ sudo, it works well. My question is, can I run the script without adding sudo? I am actually trying to implement pixy to ROS and to do that I need to run the script without sudo and avoid “Segmentation fault”

If there is any solution, I will really appreciate it. Thanks in advance

#5

Hello,
Pixy permissions are usually an issue with udev rules. Hopefully this helps:

https://docs.pixycam.com/wiki/doku.php?id=wiki:v2:installing_pixymon_on_linux#add-permissions-for-pixy-usb-interface

Edward

1 Like
#6

Thank you so much! the link you sent me worked. I really appreciate the fast response, have a good one!