Sip-and-puff or sip 'n' puff (SNP) is assistive technology used to send signals to a device using

air pressure Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars ...

by "sipping" (inhaling) or "puffing" (exhaling) on a straw, tube or "wand." It is primarily used by people who do not have the use of their hands. It is commonly used to control a

motorized wheelchair A motorized wheelchair, powerchair, electric wheelchair or electric-powered wheelchair (EPW) is a wheelchair that is propelled by means of an electric motor (usually using differential steering) rather than manual power. Motorized wheelchairs ...

by quadriplegics with very high injury to their

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the sp ...

or people with ALS.{{cite web, url=http://atwiki.assistivetech.net/index.php/Alternative_wheelchair_control , title=Alternative wheelchair control - ATWiki , publisher=Atwiki.assistivetech.net , date= , accessdate=2011-11-04

Calibration and setup

Devices that use SNP technology require specific amounts of air pressure to be "sipped" or "puffed" by the user. These amounts of pressure are typically denoted as a hard sip/hard puff or soft sip/soft puff, however other terminologies might exist. Note that the words "hard" and "soft" are relative to the user and depend on their breathing abilities. Typically, air pressure levels pertaining to hard sips/puffs and soft sips/puffs are set through an initial

calibration In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration standard of known accuracy. Such a standard could be another measurement device of kno ...

of the pressure sensor completed before the user starts to use their SNP device. With the assistance of an aid or technician, the user will program the SNP device to recognize their body's ability to produce hard sips/puffs and soft sips/puffs. Once this calibration process is complete, the SNP device will only recognize the user specific sips and puffs that have been saved into the SNP device.

Motorized wheelchair control

Typical applications of Sip-and-Puff devices are for control of a

. Control typically consists of four different inputs from the user. An initial hard puff will enable the wheelchair to move forward, while a hard sip will stop the wheelchair. Conversely, an initial hard sip will enable the wheelchair to move backward, while a hard puff will stop the wheelchair. A continuous soft sip or soft puff will enable the wheelchair to move left or right respectively depending on how long the user blows into the tube, straw or "wand".

Computer input device

The mouth-controlled input provide users a simple and effective way to control mouse movement. Movement and operation of this joystick is similar to that of a mouth stick. Mouse button clicking is accomplished with the help of sips or puffs function of the joystick. A sip-and-puff input device combined with

computer accessibility Computer accessibility (also known as accessible computing) refers to the accessibility of a computer system to all people, regardless of disability type or severity of impairment. The term ''accessibility'' is most often used in reference to spe ...

software means many

keyboard Keyboard may refer to: Text input * Keyboard, part of a typewriter * Computer keyboard ** Keyboard layout, the software control of computer keyboards and their mapping ** Keyboard technology, computer keyboard hardware and firmware Music * Musi ...

-accessible programs can be used with this device.

References

External links

What is a Sip-N-Puff device?
* http://www.theallineed.com/engineering/06082931.htm * http://www.wheelchairnet.org/WCN_ProdServ/Products/adldev.html * http://atwiki.assistivetech.net/index.php/Alternative_wheelchair_control Assistive technology