Differentialpilot over bluetooth delay

[maigel]

Hi,

I'm currently using the Lejos eclipse plugin to create a PC project. This project sets up a bluetooth connection for me so I can remotly send commands to the NXJ.
Now I'm trying to write a program that allows me to use my arrow keys on my laptop to control the robot.
I tried using a DifferentialPilot object to send the forward(), backward(), etc messages. Where as this works, I can notice a pretty hard delay on it. When I press a key the robot starts moving 1 - 1.5 seconds later.

If I use a RemoteMotor object and write my own forward, rotate etc functions directly controlling the RemoteMotor's the delay is gone.

Though, I would prefer to use a differentialpilot, does anyone know what causes the delay/lag and how to fix it?

[skoehler]

If delay matters, don't control use DifferentialPilot on the PC, but instead write a program that runs locally on the NXT. Of course, that program can communicate with a program running on the PC.

[maigel]

So there's no way to fix the delay with only the program running on the pc?

[skoehler]

So there's no way to fix the delay with only the program running on the pc?

Not really.

[maigel]

What I don't get though, is when I use for example

Code: Select all

Motor.A.forward();
Motor.B.forward();

instead of

Code: Select all

pilot.forward();

to tell my robot to go forward, the first one with the motor's has a way lower delay

[gloomyandy]

Not surprisingly this is probably because the Differential pilot version does a lot more than simply making the motors move forward. So perhaps you could reduce the delay by writing your own version of the pilot (after all you have the source code). But as Sven has already mentioned to get good real time control the best way will almost certainly be to have some of your code running on the NXT and use your own protocol between the PC and the NXT.

[maigel]

Turns out it's the inbuilt motorlisteners in the differential pilot class causing the delay.

Thanks all for the help!