Great low-cost, open-source “sip-and-puff” interface to control toys for people with and without limited mobility! Via Bobpardiso.com
Sip-and-puff is one of many ways someone can control a device without having to use their hands, and is a useful method for some people with certain disabilities. A puff is blowing into the tube, and a sip is sucking from the tube. In both cases the required pressure is tuned to the user for ease of use and can be very light to lessen fatigue. There are many sip-and-puff controls on the market for various things, but they can be expensive or difficult to customize. What I’m showing here is an extremely affordable, simple to build, and fully customizable sip-and-puff setup used to control two different remote control toys that have very different controls.
Detecting the sips and puffs is done with a pressure sensor. For this project I chose the MPXV7007G: http://cache.freescale.com/files/sensors/doc/data_sheet/MPXV7007.pdf
This sensor takes -1 to 1 psi as input and maps it to 0.5 to 4.5V as output if you power it at 5V. This nicely sets the full scale as a strong sip to a strong puff and still allows specifically detecting soft sips and puffs. To make it easier to prototype with I soldered on a 4 pin male header and then added hot glue for mechanical support as pictured below.