Sip-and-puff or sip 'n' puff (SNP) is

assistive technology Assistive technology (AT) is a term for assistive, adaptive, and rehabilitative devices for people with disabilities and the elderly. Disabled people often have difficulty performing activities of daily living (ADLs) independently, or even with ...

used to send signals to a device using air pressure 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 by

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with very high injury to their spinal cord or people with

ALS Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most com ...

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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 of the

pressure sensor A pressure sensor is a device for pressure measurement of gases or liquids. Pressure is an expression of the force required to stop a fluid from expanding, and is usually stated in terms of force per unit area. A pressure sensor usually act ...

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 motorized wheelchair. 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

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movement. Movement and operation of this

joystick A joystick, sometimes called a flight stick, is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. A joystick, also known as the control column, is the principal cont ...

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 software means many keyboard-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