The 'Sup - a Mouse for Quadriplegics - Low Cost and Open Source

A friend and I recently worked on creating a device for a Quadriplegic they know to allow him to use his computer. After some research, we decided on a “Sip-n-puff” combined with a joystick to give Allen the ability to move the cursor around the screen a click things.
A Sip-n-puff is an input device that takes user input in the form of a “Sip” or a “Puff” (Imagine sipping through a straw, or blowing bubbles in your drink). Here, we combine it with a joystick to enable the user to move the cursor on-screen, and the Sip-n-puff is used for functions such as clicking and scrolling.
Sip-n-puff devices are nothing new, and joystick/sip-n-puff combos aren’t too uncommon either- But to buy such a device will cost you around $500 to $1500! For Allen, who has no source of income, that’s an impossible price. However, the device itself is actually very simple- In this ‘ible, I’ll show you how to build one for just under $50!
All the designs and code are open source, which means you can build one without paying me a dime! If you’d like just the finished device without the work, I’d be happy to make one for you- Details at the end of the Instructable.
Finally, since this is open source, you can find all the design files and code at the GitHub:”