I'm working on a python app that's reading from a gps usb dongle. This far everything has been running in ubuntu/debian based systems where I communicated with the gps in a rather blunt way of scanning all of /dev/ttyUSB0-9 with pySerial for something speaking NMEA sentences on 38400 baud. Now I have been asked to get this app working cross platform and I'm a bit confused on which would be the best way of finding the gps dongle.
I have considered something along the lines of:
if os.name == "posix":
self.conn = serial.Serial("/dev/ttyUSB%i" % usb)
elif os.name == "nt":
...
But I would rather have a single solution that works cross platform. Does anyone know of such a solution?
You could use the comports function from the scanwin32.py module provided in the pySerial documentation to figure out which COM ports are available, and then, using the returned informations about the open ports, find which one is your GPS dongle.
Edit: The documentation also provides a scan.py module which contains only a very simple function that probes each 256 ports to find which ones are open, maybe it would be sufficient for what you need.
I would guess that in the long run you may have more use of a cross platform anyway so go for why not stay with it?
Related
If i have two keyboards (default keyboard and an RFID reader) in my Linux machine
Using python how can I know from which device the input is coming from ?
I can read my input using the
input()
but i need to distinguish between the two devices
I'm assuming the RFID reader works on USB, if that's the case, should be treated like an input device as well as the HID Keybord (I'm assuming HID by your default).
I'm using evdev in python to do something similar for myself.
You can find the documentation here: http://python-evdev.readthedocs.io/en/latest/tutorial.html#reading-events
It has lots of simple and useful examples, like identify and read from multiple devices asynchronously.
I found it very easy to use.
I want to experiment with the PN532 that comes connected with an arduino UNO. I have never touched anything similar, and in fact it took me quite a few tries to be able to play with LEDs on another arduino board I have.
Can someone provide me with a concrete example of reading data from the pn532 when I use a tag or card on it in Python?
Take a look at https://github.com/HubCityLabs/py532lib. The standard library is in C, somebody wrote a Python wrapper for the C library that you can use.
I did found a way that might be partially correct. Since Eugenes' answer does not provide a definitive way that we know will work, it cannot be considered a full answer so I will most probably accept this one if nothing else changes.
First of all since the PN532 does not continuously monitor for signals and emits data, we will have to program it the usual way in order for it to behave according to what we want to achieve.
This can be done using the same software that you program any other Arduino device.
Make sure you have chosen the correct port from the tools menu. If you don't know which port is that, in windows go to Start>All Programs>Accessories>System Tools>System Information>Components>Ports>Serial. For Linux going to /dev/serial/by-id should do.
Then I would recommend using the examples provided by the manufacturer here. Make sure you choose the right connection type or else you will see no data coming from the device (Most probably you will want I2C).
Once that is done, and your device emits data each time a tag is used on it (check with a serial terminal configured at 115200 Baud rate) then you are ready to start working with python.
Again I recommend this module to read your data from the serial port. It even comes with a ready to use example of a wxWidgets terminal to read your data from the PN532. If of curse you use another python library and you think its better do say so in the comments.
I'm looking to see if there is a way to connect or disconnect to a wireless network in python, preferably a way that would work for both public and secured networks if I supplied the password. If I can configure the options about wireless, that would be an added bonus (ex. see all networks in range, see information about networks in range (like encryption type)). I run a windows computer, so I see many answers to this question in Linux, or other operating systems, but none in windows. Thanks in advance.
You'll probably have to use one of the DLLs in windows for that. Using ctypes you can get access to the win32 API from Python.
It looks like the functions from wlanapi.dll, starting with WlanOpenHandle and WlanEnumInterfaces might do what you want.
Edit: For example code, see the accepted answer to this.
A friend asked me for a program to switch his integrated wifi card off and on. I've googled it with no luck. Can someone tell me if there's any way to do that natively in python?
Does the solution have to be native? I would use a utility called 'devcon' which is created by Microsoft. You could use Python to call devcon and parse the output and disable the required device(s).
Here's an example:
http://en.kioskea.net/faq/1886-enable-disable-a-device-from-the-command-line
You can get the list of network devices with
devcon hwids =net
You can try to parse the one with WiFi in it and the lines that start with PCI.
Or you can do something like:
devcon disable hwids =net, unfortunately this disables the ethernet devices as well.
If you need to just disconnect from WiFi you can use netsh wlan disconnect
EDIT: Ok, finally found the perfect solution (IMHO).
You will need to install two packages pywin32 and wmi.
Using WMI (Windows Management Instrumentation) bindings for Python this becomes pretty easy.
import wmi
cur=wmi.WMI()
wireless_devices=cur.query("select * from Win32_NetworkAdapter WHERE NetConnectionID = 'Wireless Network Connection'")
for device in wireless_devices:
device.Disable()
If it returns a tuple with the first value of (0) it succeeded. Obviously, this must be run as an administrator (otherwise you will get 5 as the return value).
If there is a way to do it from the win32 API in C/C++ (I honestly don't know), then you can use the pywin32 bindings to do it from Python.
I have a robotics type project with an Arduino Uno, and to make a long story short, I am experimenting with some AI algorithms. However, I need to implement some high level matrix algorithms that would be quite simple using NumPy/SciPy, but they are an utter nightmare in C or C++. Even with the libraries out there, this is just getting ridiculous.
Is there any way I can do this project in Python? I think I heard something about the Mega having this capability, but I have an Uno, and replacing it is not an option at this point (that would set the project back quite a bit.) Also, I heard somethings about using Python to communicate to the Arduino via USB, but I cannot have the USB cable in while the thing is running. I need to be able to upload the program and be done with it.
Are there any options out there, or have I just reached a dead end?
There was a talk about using Python with robotics at this years PyConAU called Ah! I see you have the machine that goes 'BING'! by Dr. Graeme Cross.
The only option he recommended for using Python on a microcontroller board was PyMite which I think also goes by the name of Python-On-A-Chip.
It has been ported to a range of boards - specifically he mentions the Arduino Mega which you said is not an option for you, but it is possible it is supported on other Arduino boards.
However, because it is a "batteries not included" version of Python it is more than likely that you will have a real problem getting numpy/scipy etc up and running.
As other posters have suggested, implementing in C might be the path of least resistence.
Update: again, not specifically for Arduino, but pyMCU looks to provide python on a chip. The author states he may look at developing an Arduino version of pyMCU if there is enough interest.
I've started work on a "Little Python" to C++ (called Pyxie - a play on Py CC- Pyc-C) compiler, with the specific aim of compiling a sane subset of python to C++ such that it can run on an arduino.
This is far from complete at time of writing (0.0.16), but it can currently compile a very small subset of python - enough for the arduino "blink" example to run. To support this, it has a compilation profile - which essentially means "compile using the arduino toolchain."
A program it can compile looks like this:
led = 13
pinMode(led, OUTPUT)
while True:
digitalWrite(led, HIGH)
delay(1000)
digitalWrite(led, LOW)
delay(1000)
This parses, performs analysis (like type inference, etc), compiles to C++, which is then compiled to a hex file, which you can load onto your device.
There's a long way to go before it's useful, but it is progressing and does have a roadmap/etc.
PyPI - http://pypi.python.org/pypi/pyxie
Homepage - http://www.sparkslabs.com/pyxie/index.html
In particular a key difference from Micropython (and PyMite) is that it's designed to compile to devices too small to run either implementation. (This also means it's very different from things like ShedSkin which while a Python to C++ compiler target larger execution environments)
It's going to be difficult to get any kind of Python script running directly on the Arduino uno.Reason is that it is an interpreted language, so you will need a interpreter on-board in addition to the plain text script. There is probably not going to be enough memory for all of thatin arduino uno.
What you can do best is to find a way to compile a Python script to native machine code (this is how C/C++ works). I have seen projects around to do something like that for other platforms, but (as far as I know) none which does it successfully for Arduino uno yet.
you can visit http://www.toptechboy.com/using-python-with-arduino-lessons/ for more.
wish this will help you.
thanks!
This is not a direct solution but in your circumstances If I were you, I would write the AI program on my computer and the rest of it in Arduino. after that I would write a flask server with my AI program. and then, port forward from my router to the local machine. finally, make requests from Arduino to the server.