Just back from a few days in Bristol working with Duncan Speakman and Kathy Hinde making some mobile sound installations using PDa on the gumstix.
We were interfacing phidget USB sensor boards which allow a wide variety of sensors to be conveniently accessed.
I am very impressed by the phidgets ease of use and the quality of their documentation: however there is no off-the shelf way of talking to them in pure data.
One result is a new external for pd and PDa for the phidget 8×8x8 interfaceKit (linux only).
you need to download and make the phidget linux library
make & sudo make install
The external allows you to set the digital outputs, read the digital & analogue inputs, and set the threshold sensitivity for the ADCs.