I am trying out the Turtlebot stack under Electric (beta). So far everything works great including the follower application. Next I want to control two Dynamixel AX-12 servos that I have attached to the Kinect for pan and tilt. The Create is on port /dev/ttyUSB1 and my USB2Dynamixel controller is on /dev/ttyUSB0 and I am using the dynamixel_motor package to control the servos.
When I launch the Turtlebot using the minimal.launch file, everything comes up fine on /dev/ttyUSB1. But as soon as I launch the dynamixel_motor controllers (which comes up fine on /dev/ttyUSB0), I get the following error in the Turtlebot launch window:
Failed to contact device with error: [Error reading from SCI port. Wrong data length.]. Please check that the Create is powered on and that the connector is plugged into the Create.[turtlebot_node-3] process has finished cleanly.
log file: /home/patrick/.ros/log/28a03a10-bb09-11e0-bde5-00271017076c/turtlebot_node-3*.log
[turtlebot_node-3] restarting process
process[turtlebot_node-3]: started with pid 
This block then just keeps repeating indefinitely.
Has anyone else experienced something similar?
Post score: 0
Comment by Pi Robot on 2011-07-31:
Thanks Alaina--that did the trick! If you post your comment as an answer, I can accept it as the correct answer.
Comment by Alaina on 2011-07-31:
Have you tried setting your udev rules to make the SCI port /dev/ttyUSB0 and your USB2Dynamixel controller /dev/ttyUSB1? I have a Logitech webcam running on /dev/ttyUSB1 with no problems.