[ros-users] NXT Ultrasonic sensor

[Melonee Wise]

Yes I understand...I need to look into the problem more carefully Monday.. My thoughts are right now to put a try and catch in for the exception and to take another look at the raw nxt stream and see if there is anything I missed the first time I stumbled upon this problem.. If you want to work on it some more try looking at usbsock.py in nxt_python you can set debug to True and look at the data coming over the wire. 

-Melonee

On Aug 8, 2010, at 4:49 AM, Max B <skinkworks42 at gmail.com> wrote:

> You say this happens periodically, but for me, it happens almost every time I run nxt_ros. I have set nxt_ros to respawn in the launch file, and it just keeps respawning. I applied the fix noted in Issue 5 on the nxt-python bug tracker, but it provided no help either.
> 
> From,
>     Max
> 
> On Sat, Aug 7, 2010 at 6:08 PM, Melonee Wise <mwise at willowgarage.com> wrote:
> This is a problem in the underlying driver in nxt_python... It occurs when the I2C bus is pulled too quickly by the python library... I will look more into a more permanent fix on monday morning since I don't have a brick at home. For now if it only happens periodically set nxt_ros respawn in your launch file..
> 
> -Melonee
> 
> On Aug 7, 2010, at 2:34 PM, Max B <skinkworks42 at gmail.com> wrote:
> 
> > Hello,
> >     I am using cturtle from the Ubuntu Lucid repositories, with the svn version of the nxt stack. I am running Ubuntu Lucid x64 with kernel 2.6.32-generic. I have an NXT controller, and I am trying to use it with ROS. I have an ultrasonic sensor configured for use on the robot. When I run nxt_ros with bluetooth, I get the error "nxt.error.I2CError: ls_get_status timeout" when it is setting up the sensors, and nxt_ros dies. When I use USB, I get the error "usb.USBError: No error" and nxt_ros dies. What can I do to fix this? If I comment out the ultrasonic sensor from the yaml file (and just leave two motors and a gyro), the process runs just fine.
> > From,
> >    Max
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