Check it out, a Sip-and-Puff Arduino shield. This is an assistive technology that allows the physically challenged to control things using a plastic air tube. Different combinations of sucking (Sip) or blowing (Puff) differentiate between control commands.
In this case the device is used to control an iPod dock, but [Bob Johnson's] Kickstarter project seeks to put the Sip-and-Puff functionality out there so that it can bridge the control gap no matter what the need. One example that he mentions in the video after the break is a Morse Code keyboard.
This shield uses a pressure sensor to receive input from the plastic tubing. But we’ve also seen it done using mechanical pressure switches. That technique is what was used in the Sip-and-Puff Kayak build.