Not a hardware issue. When I run the example code I get import error: “no module named wiringpi2”
Any insite on why this is happening? Any other information I need to provide in order to get this fixed?
I fallowed the directions exactly on how to install the DRV8835 library from github.
Hello, Loren.
From the error you are getting, it sounds like the WiringPi2-Python library might not have installed correctly. Can you try re-entering the commands for downloading and installing WiringPi2-Python listed in the “Installation” section of the Python library for the DRV8835 Dual Motor Driver Kit for Raspberry Pi GitHub page? Can you post a copy of the output you get when you run those commands?
Brandon
HI BrandonM
Here are the steps exactly as I performed them after removing
wiringpi and wiringpi2-Python folders.
open terminal.
entered “sudo apt-get install git”
git was already newest version.
entered “git clone git://git.drogon.net/wiringPi”
terminal put out:
Cloning into ‘wiringPi’…
remote: Counting objects: 1009, done.
remote: Compressing objects: 100% (831/831), done.
remote: Total 1009 (delta 715), reused 214 (delta 142)
Receiving objects: 100% (1009/1009), 327.76 KiB | 0 bytes/s, done.
Resolving deltas: 100% (715/715), done.
Checking connectivity… done.
Entered “cd wiringPi”
Terminal changed directory
Entered ./build
Terminal did stuff then said All done.
Terminal also made this note:
NOTE: To compile programs with wiringPi, you need to add:
-lwiringPi
to your compile line(s) To use the Gertboard, MaxDetect, etc.
code (the devLib), you need to also add:
-lwiringPiDev
to your compile line(s).
I then closed out terminal.
Then I moved to the next step of downloading and installing wiringpi 2
Close terminal.
Finally last steps:
Close out terminal
Steps taken to try running the example program:
Open terminal
Enter: cd /home/pi/drv8835-motor-driver-rpi
Enter: ls
Terminal outputs:
build example.py pololu_drv8835_rpi.py README.textile setup.py
Enter sudo python example.py
AND dang it.
lol it worked.
I think my frustration was trying to get this to go in python3 which is what I learned on.
So I guess I’ll just figure out the difference between the 2 and program this in python 2.
Unless you could point out what I need to do differently to install this stuff for python 3.
I am glad it is working for you now; thank you for letting me know.
The “Installation” section of the GitHub page for the library (that I linked to in my first post) has instructions for different versions of Python:
Brandon
Ok I re-removed the files as I really want this to work in python 3.
Here are the steps I took to try to install it for python 3:
Next:
Next:
Last:
open terminal
Enter: cd /home/pi/drv8835-motor-driver-rpi
Enter: sudo python3 example.py
Terminal:
Traceback (most recent call last):
File “example.py”, line 3, in
from pololu_drv8835_rpi import motors, MAX_SPEED
File “/home/pi/drv8835-motor-driver-rpi/pololu_drv8835_rpi.py”, line 1, in
import wiringpi2
File “/usr/local/lib/python3.4/dist-packages/wiringpi2-1.1.1-py3.4-linux-armv7l.egg/wiringpi2.py”, line 28, in
_wiringpi2 = swig_import_helper()
File “/usr/local/lib/python3.4/dist-packages/wiringpi2-1.1.1-py3.4-linux-armv7l.egg/wiringpi2.py”, line 24, in swig_import_helper
_mod = imp.load_module(’_wiringpi2’, fp, pathname, description)
File “/usr/lib/python3.4/imp.py”, line 243, in load_module
return load_dynamic(name, filename, file)
ImportError: /usr/local/lib/python3.4/dist-packages/wiringpi2-1.1.1-py3.4-linux-armv7l.egg/_wiringpi2.cpython-34m.so: undefined symbol: PyString_FromStringAndSize
Last thing: entering “sudo python example.py” will still run the example. However doesn’t this mean I’m still running it in python 2?
Hello.
Yes, on Raspbian and other Debian-based systems, the command python usually corresponds to Python 2. You can check this by running python --version. So if you run sudo python example.py, you are still using Python 2.
I looked into the error you were getting and it turned out that it was a bug in the WiringPi2-Python repository, and that repository is deprecated. We just published a new version of the drv8835-motor-driver-rpi library which fixes this problem, and it has simpler instructions that should work with both Python 2 and Python 3. Please try the new instructions and let me know if you have any issues.
–David
I just wanted to thank you for successfully helping me fix this. Both python 2 and 3 will now run the example so I can finally get to programming now. 
