Problem to run weatherstation.py "No USB libary found"

[Hoggel0815]

Hi,

i try to run on my RaspberryPi4 with Python3.7 the weatherstation.py, to get some easy weatherinformations for a own python Projekt, but everything i´ve try to run the programm doesent work and i end up with No USB libary found".

I´ve trying "pip3 install libusb", "pip3 install usb", "sudo apt-get install python-libusb1.0.0", "sudo apt-get install python-usb", "pip3 install pyusb"

Any ideas to try something else?

[jim-easterbrook]

Try sudo apt-get install python3-libusb1 to install the Python 3 version instead of the Python 2 version.

[Hoggel0815]

Thanks for the fast answere, but the problem still "No USB libary found". I try to run the example code in weatherstation.py

`import weatherstation

ws = weatherstation.WeatherStation() print(ws.get_fixed_block(['min', 'temp_out', 'val']))`

[jim-easterbrook]

Remove all the pip installed USB stuff and reinstall python3-libusb1 with apt. As it relies on a C library (libusb1) it is much safer to install with apt as that should install the C dependency. then try running pywws-testweatherstation.

[Hoggel0815]

I´ve tried it on a fresh other RaspberryPi to run the testweatherstation, but the same issue

[jim-easterbrook]

What's the output of dpkg -l | grep -i libusb?

[Hoggel0815]

ii libusb-0.1-4:armhf 2:0.1.12-32 armhf userspace USB programming library ii libusb-1.0-0:armhf 2:1.0.22-2 armhf userspace USB programming library ii libusb-1.0-doc 2:1.0.22-2 all documentation for userspace USB programming ii libusbmuxd4:armhf 1.1.0~git20181007.07a493a-1 armhf USB multiplexor daemon for iPhone and iPod Touch devices - library ii python3-libusb1 1.7-1 all Python wrapper for libusb1 (Python 3)

[jim-easterbrook]

That's all looking good. What about python3 -c "import pywws.weatherstation"?

[Hoggel0815]

that work´s no output

[jim-easterbrook]

OK, I think python3 -m pywws.testweatherstation should work, in which case pywws is installed and working.

[Hoggel0815]

Yeah, but

Traceback (most recent call last): File "/usr/lib/python3.7/runpy.py", line 193, in _run_module_as_main "main", mod_spec) File "/usr/lib/python3.7/runpy.py", line 85, in _run_code exec(code, run_globals) File "/home/pi/.local/lib/python3.7/site-packages/pywws/testweatherstation.py", line 190, in sys.exit(main()) File "/home/pi/.local/lib/python3.7/site-packages/pywws/testweatherstation.py", line 117, in main ws = pywws.weatherstation.WeatherStation() File "/home/pi/.local/lib/python3.7/site-packages/pywws/weatherstation.py", line 464, in init self.cusb = CUSBDrive() File "/home/pi/.local/lib/python3.7/site-packages/pywws/weatherstation.py", line 318, in init self.dev = USBDevice(0x1941, 0x8021) File "/home/pi/.local/lib/python3.7/site-packages/pywws/device_libusb1.py", line 77, in init self.dev = self.context.openByVendorIDAndProductID(idVendor, idProduct) File "/usr/lib/python3/dist-packages/usb1/init.py", line 2391, in openByVendorIDAndProductID return result.open() File "/usr/lib/python3/dist-packages/usb1/init.py", line 2159, in open mayRaiseUSBError(libusb1.libusb_open(self.device_p, byref(handle))) File "/usr/lib/python3/dist-packages/usb1/init.py", line 133, in mayRaiseUSBError raiseUSBError(value) File "/usr/lib/python3/dist-packages/usb1/init.py", line 125, in raiseUSBError raise STATUS_TO_EXCEPTION_DICT.get(value, __USBError)(value) usb1.USBErrorAccess: LIBUSB_ERROR_ACCESS [-3]

[jim-easterbrook]

That's probably because your user account doesn't have permission to access the station's USB port. You can either run everything as root (not a good idea) or set a udev rule to change ownership or permissions on the USB port. https://pywws.readthedocs.io/en/latest/guides/getstarted.html?highlight=udev#test-the-weather-station-connection

[Hoggel0815]

Ok, my Mission was to get simple weather informations like temperature in and out, wind speed, wind direction, rainfall.

So i want to create a object from weatherherstation and thought to get informations over ws.get_fixed_block(['min', 'temp_out', 'val'])` in my programm, for example.

Is that feasible?

[jim-easterbrook]

The "fixed block" probably isn't what you want - it stores things like the highest and lowest temperature the station has ever recorded. Have a look at the pywws.testweatherstation module. Its -h option fetches the most recently logged data which includes temperatures and wind direction.

Rainfall is slightly tricky as the data is a cumulative amount since the outside sensors were last reset. You'll need to store a previous reading and compare the two to see how much rain has fallen in that time interval.

[Hoggel0815]

Now i got enough to work with, you are great thanks a lot @jim-easterbrook

import pywws.weatherstation
import pprint

def raw_dump(pos, data):
    print("%04x" % pos, end=' ')
    for item in data:
        print("%02x" % item, end=' ')
    print('')

ws = pywws.weatherstation.WeatherStation()

history_count = 10

fixed_block = ws.get_fixed_block()
ptr = fixed_block['current_pos']
for i in range(history_count):
    print("0x%04x" % ptr, end=' ')
    data = ws.get_data(ptr)
    pprint.pprint(data)
    ptr = ws.dec_ptr(ptr)