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ImportError: No module named 'ow' Python 3.5.3

3118 Views - Created 26/04/2018

26/04/2018

Posted by:
Kaiden

Hi,

I started a project in Pyton 3. I use Tkinter to make a graphical interface of my project. I use a Raspberry. I want to use 1-wire to control sensors, so I use owfs with i2c.

After exchanging wih someone, he told me that Python 3 did not use the right way to find "ow".

Then I decided to try Python 2 and it seems to work. A different error appears.

I use this code for test :

import ow ow.init('localhost4304')for sensor in sensorlist:     print('Device Found')     print('Address:' + sensor.address)     print('Family:' + sensor.family)     print('ID:' + sensor.id)     print('Type:' + sensor.type)     print('')

In Python 2 the error comes from ow.init line 224 "Raise exNoController".

My problem is that I want to use "ow" in python 3 but i can't access it. Do you have an idea to solve my problem ?

Maybe I've to use : python3 -m pip install ****** ? I should replace the stars by ?

Thanks,

-K

26/04/2018

Posted by:
andrew

Location:
United Kingdom

Hi

The Raise exNoController error is probably being caused by the owserver not running. There is a thread in this forum post with someone else who had the same problem and a way to fix it. Hopefully, this is the same problem you are having.

python-ow is not available in Python 3 but it is possible to access the 1-wire sensors directly through the file system. The code below shows how to mount owfs using a subprocess call and then read the temperature from a sensor by accessing it directly through the file system. You would need to update the Sensor1 variable to point to the path of your 1-wire sensor. This method should work with python 2 and 3.

#!/usr/bin/pythonimport osimport subprocessimport time# mount owfssubprocess.call(["owfs", "--i2c=ALL:ALL", "--allow_other", "/mnt/1wire/"])# 1 wire temperature sensorsSensor1 = "/mnt/1wire/10.BA7392020800/temperature"varSensor1Value = 0.0def get_1wire_sensor(path):    #    # Function to read 1-Wire sensors using OWFS    #    try:        f = open(path, "r")        text = f.readlines()        f.close()        return float(text[0]) + 3    except:        print("getwiretemp failed")    return 88while (True):    varSensor1Value = get_1wire_sensor(Sensor1)    print(varSensor1Value)    time.sleep(1)

26/04/2018

Posted by:
Kaiden

Hi Andrew,

Thanks for the support.

I've test your code and i think that will solve my problem, but now, there is actually this problem with owserver... i get "getwiretemp failed 88" when i execute the code.

I've follow all your tutorial but i've problem when i write this command: sudo /opt/owfs/bin/owserver -c /etc/owfs.conf --pid-file /var/run/owfs/owserver.pid

It shows me an error: sudo: /opt/owfs/bin/owserver : command not found.

Where's the problem ?

Thanks,

-K

26/04/2018

Posted by:
Kaiden

Re,

Many thanks for your help, that has fixed the problem.

I found the second problem, i forgot to change the sensor "Sensor1" That's why there was this problem.

Thanks a lot for your help !

-K

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