Finally a breath-based joystick!
I finally managed to find a breath-base joystick:Evreinov G., Evreinova T. "Breath-Joystick" – Graphical Manipulator for Physically Disabled Users. In Proceedings of the 7th International Conference on Computer Helping People with Special Needs. ICCHP2000, July 17-21, 2000, Karlsruhe, Germany, pp. 193-199. Unfortunately there is no picture of the device.
Manipulator of joystick’s type was implemented as device having a high sensitivity to human respiration flow. A circuit diagram of the breath-joystick is shown in Figure 1.
Six thermo-transducers are located in front of user’s mouth on a surface having special elements of construction, which are dividing and selecting necessary components of directed air stream. Thus, a prototype implements a function of two-dimension thermo-converter of coordinates, while two others thermo-transducers must emulated a function of buttons. Thermo-transducers have a temperature little bit above than environmental one (about 40?C), it allows to remove undesirable influence of a water vapor, being in air flow.