Finally I got around to have some practice with gHowl. Before the first release of the tool, I had tried to link my iPhone both with Processing and Grasshopper, unfortunately without success.
This time everythink seems to work pretty fine, even if a little bit slowly!
TouchOSC is a universal iPhone application that lets you send and receive Open Sound Control messages over a Wi-Fi network using the UDP protocol. Together with his relative editor you can to design custom layouts (see Hexler.net’s for more informations and basic code http://hexler.net/software/touchosc).
The OSC message contains data coming from a customized touch XYpad and the accelerometer (the latter is the triplet of data: x-rot, z-rot, orientation). Once it has been received, gHowl delivers the content of the message to Processing, in order to provide a minimal visualization of any tracked data.
Maybe, as have already seen in my previous explorations, the test-wall shows adaptive behaviour by changing his porosity: the cursor coordinates on the touch XYpad (on the iPhone) are remapped conveniently to the surface's UV domain to define the varying position of an attractor point.
One further control is provided by a sort of 'switch' for the openings of the wall: the point attractor strategy is suddenly lost whenever the orientation (i.e. y-rot) assumes values within the ranges (0.9;1) and (-1;-0.9). That is, the iPhone is nearly horizontal. Only in that position the remote controller closes the entire panels.
more about gHowl @ Grasshopper forum: http://www.grasshopper3d.com/group/ghowl