The linux driver allready does this for you (partly). The thing is that a ff device is a small robot, with onboard memory and 2 motors. F.i. for periodic effects the waveform can be uploaded.
Simulated direct control of the force is easy. You upload a constant force object with infinite duration, and then change the force and the direction. With periodic effects you can change the period and the force ad the direction. You have to start and stop to change the waveform I think, although the driver may take care of this. It is a bit device dependent I think. Of course this is still not the same as directly controlling the electrical motors. But that is impossible I think, they are controlled by the electronics in the joystick, and that reacts to certain USB messages. Besides, if you want that, there are easier and cheaper ways to control electrical motors with a computer.
I will send the code to you over the weekend.
Gerard
Hans-Christoph Steiner said at "Re: Force Feedback Joysticks."r[2003/03/04 03:54]
What I would really love to do is be able to control the forces and vibrations directly from PD, rather than having to load pre-built 'effects'. From what I've read, it might be possible to emulate this by dynamically switching effects, but that seems like a bit of a pain to code. I just found the linux FF API and have only started looking into it. Is there any way to directly control the forces and vibrations?
I look forward to getting your code. I have also been trying to think of a way to incorporate FF into jsarlo's joystick object, but I haven't figured that one out yet.
.hc