The TOOB
The TOOB Controller (standing for Totally Obnoxious and Offensive Butterfly, or Tube-Oriented Optical Bookend, or whatever you desire) is an expressive wireless wind controller that also senses finger pressure and motion.
Check out this video of Greg Souza and I performing at the Brown music dept graduation recital (we closed a show composed otherwise of classical music!)
The instrument is made up of two housings, one held in each hand, connected by a flexible tube that allows them to move independently of each other. Modeled after a trumpet, the right hand housing contains the breath sensor and three finger pressure pads. This section also contains most of the electronics, including the microcontroller, sensor conditioning circuits and bluetooth wireless transmitter. The left hand housing is smaller and contains a motion sensor (a 3-axis accelerometer) and three additional finger pressure pads.
The TOOB software is still a work in progress, but the basic premise is painting in the frequency spectrum. Blowing into the instrument allows a peak of frequencies from a noisy audio sample through a spectral filter. The frequencies let though depend on the left (low pitch) and right (high pitch) tilt of the left hand section of the instrument. The decay of this frequency peak as well as its width are controlled with finger pressure on the left hand and the looping speed of the original audio file is modulated by froward and backward tilt.
The right hand fingers control the input, feedback and length of a custom delay system. The 3rd finger on the left hand controls a completely independent synthesis process triggered by any motion of the left hand section which sounds somewhat like the creaking of a ship's timbers.
The TOOB does breath sensing with a simple piezo sensor purchased at Radioshack, the output of which is minimally smoothed with an analog RC filter and boosted using an Op-Amp.
A 3-axis analog accelerometer senses motion in the left hand section, picking up pitch, roll and upside-down/right-side-up orientation as well as any sudden jerky movements left/right or front/back (Jerky motions are currently used to switch between noisy samples). The analog outputs of the accelerometer are
The finger pressure pads are FSRs from Interlink electronics. They sense force and are analog, so they detect how much force you are using, not just if you are pressing/not pressing.
The Bluetooth transmitter claims a range of up to 100 ft through walls and 300 ft in direct view of the reciever (my powerbook). I have not tested the limits of this, but I have done my own soundchecks by standing in the audience of the hall and playing!
For analog to digital conversion and data acquisition I am using a PIC microcontroller that I programmed in C. And yes - you can do that on a mac nowdays.