Errors when using joy

Error: Couldn't open joystick

•  user@prX:rosrun joy joy_node
  [ INFO] 1254256422.863852000: Started node [/joy_node], pid [24689], bound on [nsf], xmlrpc port [56918], tcpros port [33023], logging to [/u/watts/ros/rc/log/joy_node_24689.log], using [real] time
  [ERROR] 1254256422.883483000: Couldn't open joystick /dev/input/js0. Will retry every second.

Solution:

• Is the joystick connected?
  • The joystick won't work if it's not plugged in. Connect the joystick and retry.
• Machine set correctly This can also mean you're running joy_node on the wrong machine. Make sure you're running the node on the right machine. Check to make sure that the port is open.

ls -l /dev/input/js0

You may have to add permissions:

chmod +rw /dev/input/js0

• If you're sure you're connected, try using jstest to view the joystick.

sudo jstest /dev/input/js0

• PS3 joystick not connected.

If you're using a PS3 joystick, you will have to pair it properly, and connect it. See: Pairing a PS3 joystick.

Error: Joystick control is inaccurate / moves robot when deadman switch is pressed

(This one assumes you are encountering the error while using teleop_joystick.launch) Use  rostopic echo joy  to see the joystick commands being sent out. When the joysticks are at rest (centered) all of the axes should be 0. If they are not, then the joystick itself is malfunctioning. Try removing its batteries and putting them back in.

It may also be necessary to re-mate the joystick to the wireless receiver in order to re-zero the joystick axes.