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Hi! I alwasy run some command in terminal like:
sudo chmod 777 /dev/USB0
sudo chmod 777 /dev/ACM0
but how can i do this in launch file, when i ask roslaunch expamle.launch it call this shell programming for once?
You should really configure your system so that you don't have to manually modify device permissions on startup.
For serial devices on most Linux systems, that usually just means adding yourself to the proper group that has access to the serial device, or modifying the udev rules.
You can verify which group has access to the devices by doing ls -l /dev/ttyACM0 /dev/ttyUSB0 ; then add yourself to that group. For example, on Ubuntu the group is dialout, so you would do:
sudo usermod -a -G dialout USER
Put these commands into an executable shell script (let's call it yourscript.sh) somewhere inside the package directory (let's call the package yourpackage) and then reference that script inside your launch file (e.g. example.launch):
<node name="nodename" pkg="yourpackage" type="yourscript.sh">
@Mohsen Keep in mind that this 'script node' is started with all others in parallel. So while usually the chmods will be done before any node even starts thinking about those /devs, the worst case might be that every other node has started (and perhaps crashed) before the first chmod is called
When I use the above <node pkg="hast" type="yourScript.sh" name="yourScript"/> I get an error: ERROR: cannot launch node of type [hast/yourScript.sh]: Cannot locate node of type [yourScript.sh] in package [hast]. Is an entry to the CMakeLists file necessary?
Fixed the answer, thanks felix k. My answer is not a good one anyway. ;)
Similar to the other answer, but the other way round. Create a shell script that sets your permissions (as described above), but make the last line of this script
roslaunch example.launch
Then just run the shell script.
...but, you should really implement the solution in Austin's answer, since that's the Right Thing to do.
I agree with ahendrix answer: you should add yourself to the dialout group: it is most convenient and proper in my opinion.
For those that search for a way to run scripts or delay, see my answer here: http://answers.ros.org/question/51474...
Asked: 2013-05-28 22:02:15 -0500
Seen: 4,610 times
Last updated: Apr 24 '14
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