Even if you're not diabetic, you've probably heard that they need to watch out for problems with their feet. That's because they frequently lack sensation down there, and therefore don't know when it's time to shift their weight in order to relieve pressure on specific areas of their feet. The result can be chronic pressure sores, which can in turn ultimately lead to toe or foot amputations. While pressure-sensing shoe inserts are one option, Germany's Fraunhofer Institute for Silicate Research claims that its pressure-sensing stockings are a better way to go.
Each of the prototype socks is made from two layers of breathable, moisture-wicking cotton/synthetic fabric, between which is sandwiched a stretchable silicone film. Both sides of that film are coated with a total of 40 dielectric flexible electrodes made from graphite or carbon black. An electronics module is attached to the end of the sock, which should take the form of a button-sized removable unit in the commercial version.
When pressure is applied to one region of the foot, the silicone in that area is pressed and becomes thinner, thus increasing its surface area. This causes the electrical capacitance in that area to rise. Via conductive threads leading to the sensor(s) in that part of the sock, the electronics module detects that change, and alerts the user by wirelessly sending an alert to their mobile device.
The sensors are located adjacent the sole, heel, ankle and top of the foot. According to Fraunhofer, this allows readings to be made in three dimensions – pressure-monitoring inserts, by contrast, simply provide "flat" readings of the sole of the foot only.
The final version of the sock should be washable, with the electronics module being temporarily removed by the user. Fraunhofer envisions it not only being used by diabetics, but also by people such athletes who wish to analyze their running style and foot positioning – perhaps providing some competition for the existing Moticon sensor insole.
It is estimated that the stockings should cost around €250 (about US$280) a pair.