Re: [Java-player-users] Weird sonar issue -

[Nils O. T. <no...@gm...>]

Hi Shane,
I guess its related to the way you poll your data from the sensor, try


pc.runThreaded (-1, -1);

in the initialization section end delete the si.readData() stuff. As far 
as I see from my working code its not necessary this way.


Hope this helps

Ole

Shane Hoversten wrote:
> Hi -
> 
> I'm just starting work with playerclient using stage 1.3.5 and I'm 
> encountering some really bizarre sonar readings.  Here's a code snippet:
> 
> ----
>        ...
>        SonarInterface si = pc.requestInterfaceSonar(0, 'r');
>        ...
>        while (yes == 1) {
>            si.readData();
>            int [] r = si.getRanges();
>                      System.out.println(r[0] + " " + r[1] + " " + r[2] + 
> " " +
>                                            r[3] + " " + r[4] + " " + r[5]);
> 
>            try { Thread.sleep(1000); }
>            catch (InterruptedException e) {e.printStackTrace(); }
>        }
> ----
> 
> As you can see, all it's doing is reading sonar and printing out the 
> first six values.  The simulated robot that's executing this code is 
> completely stationary.  And yet, here's a chunk of the readings:
> 
> ----
> 5000 5000 5000 5000 5000 5000
> 5000 5000 5000 5000 5000 5000
> 34835 34835 34816 0 0 0
> 4115 34835 34835 34835 34835 34835
> 0 0 0 0 0 0
> 5000 5000 5000 5000 5000 5000
> 0 0 25 0 0 0
> 0 0 0 0 0 0
> 5000 5000 5000 5000 5000 5000
> 5000 5000 5000 5000 5000 5000
> 5000 5000 5000 5000 5000 5000
> 5000 5000 5000 5000 5000 5000
> 5000 5000 5000 5000 5000 5000
> ----
> 
> As you can see, I'm getting lots of weird bouncing around.  The robot is 
> stationary, so the readings shouldn't change (especially since this 
> example has the robot in the middle of empty space.)  When I execute the 
> same program with the same stage world using the C++ client the readings 
> are rock steady.
> 
> Does anyone know what's going on? Do I need to be checking the status of 
> the sonar and waiting for it to be ready or something?  (Since there are 
> virtually no examples available I'm doing this by looking at the c++ 
> code that comes with player and trying to backport it.  Some real 
> examples would be REALLY useful.)
> 
> Thanks,
> 
> Shane
> 
> 
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