Hello Rebble,

          To be honest, I have no experience on writing a driver for stage so far ... and I have no idea how to implement it. Sorry for that.
          Regards
            yang

Rebble :
Dear yang:
   your suggestion is right. But when i use gdb,it comes the error:
 backtrace
#0  main (argc=Cannot access memory at address 0x0
Do you know how to solve the problem?
Thanks a lot!
                          Rebble 

Hi Rebble,
     I do not use opaque proxy before...
     However, in my view, the warning message
  
 skipping subscription to unknown device
opaque:0
    
indicates that your declaration is  not valid.  The example format 
should be like this
  
driver
(
  name "opaquedriver"
  plugin "libopaquedriver"
  provides ["opaque:0"]
    
I do not think the name "relay" is a valid one since that the driver 
name should be one in the list of the libplayerdrivers:
http://playerstage.sourceforge.net/doc/Player-2.1.0/player/group__drivers.html
{for example, if your robot is iRobot Create Vacuum robot, you can use 
opaque under the "create" driver:
  
driver
(
  name "create"
  provides ["position2d:0" "power:0" "bumper:0" "ir:0" "opaque:0"]
  port "/dev/ttyS2"
)
    
}
Moreover, if you are using stage, the opaque interface is not in the 
list of supported plugins:
http://playerstage.sourceforge.net/doc/stage-3.0.1/group__player.html
Maybe it is the reason that player can not recognize the Opaque proxy 
with stage.

Regards
            yang