This sensor's design is based on the Stroke Sensor found at http://www.kobakant.at/DIY/?p=792. Please visit this site for more examples and information.
Step 1: Materials Needed
-piece of Easy Felt (this felt is a bigger sheet & also a little stiffer than regular felt)
-piece of regular felt
-stretch conductive fabric
-wonder under (iron on)
-neoprene (this need to be ironable and thicker, not the plastic sheet kind)
-conductive thread ($34.95-$39.95)
-2 LED lights (any color you choose) (pack of 5 lights of one color, $4.95)
-2 sewable coin cell battery holders ($4.95)
-2 3V coin cell batteries
*Needles, scissors, Elmer's Glue, Wonder Under, and felt can all be purchased at a local craft store such as Hobby Lobby, JoAnn's, Michaels or WalMart
*LED lights, battery holders and conductive thread can be purchased from www.sparkfun.com
*Coin cell batteries can be purchased anywhere batteries are sold. Radio Shack has a pack of 3 batteries that costs approx $13
*Stretch conductive fabric as well as the thread can be purchased from www.plugandwear.com
Step 2: Making the Conductive Strips
Take a square of the conductive fabric, it doesn't have to be huge, just large enough to cut 4 rectangles. These rectangles will be anchored to the back of the Neoprene on the four sides. Take the piece of conductive fabric and iron onto a piece of Wonder Under. Cut this into the four sensors and iron those four pieces to the back of the piece of Neoprene. Once again the size does not really matter but these pieces cannot touch.
Step 3: Conductive Thread
Step 4: Filling in the Sensor
Step 5: Attaching the Batteries & LEDs
The positive (+) end of the battery holder will be attached to the positive (+) end of the LED. The negative (-) side of the LED will be attached to one conductive fabric strip while the negative (-) side of the battery holder will be attached to the opposite side's conductive fabric strip. This layout will be used for both LEDs and battery holders. When sewing through the LEDs and the battery holders, make sure to create a strong connection by sewing through at least three times.
When sewing to the conductive fabric, make sure that the stitching goes through the fabric a few times before ending. This will make sure that a connection is made.
There is a trick however, in a felt patch needs to be used to make sure that the stitching does not cross. The easiest way to accomplish this is to sew one circuit completely and then work on the other one. When you are sewing the second circuit and come to the point where you need to sew on top of the other sewing you have previously done, take small piece of felt and sew through only the very top layer so that no stitching comes all the way through. Then lay the patch in place over the previously completed stitching and continue on to the sensor.
Step 6: Testing the Sensor
If for some reason the light is constantly on, try separating the end threads from the center ones. This should break the constant connection if there is one. Once you have everything working, it is a good idea to use some Elmer's glue and anchor down your knots on the back to make sure that they do not move or fray.
Step 7: Teaching With the Sensor
"Changes in the motion and position of the head are detected by hair cells in the vestibular apparatus of the inner ear, a series of fluid-filled membranous tubes that connect with each other and with the cochlear duct. Information about hair-cell simulation is relayed from the vestibular apparatus to the brainstem via the vestibular branch of cranial nerve VIII. Vestibular information is integrated with information from the joints, tendons, and skin, leading to the sense of posture and movement. Unexpected inputs from the vestibular system and other sensory systems can induce vertigo (Human Physiology 7th Edition, Vander, Sherman, Luciano, pg 253-255).