A high resolution pressure sensor for measurement of grip force

For patients who suffer from hand diseases, like rheumatoid arthritis, simple tasks like holding a plastic coffee cup or lifting a book are not self-evident. In order to study grip patterns and compare grip patterns between people suffering from hand diseases to those of healthy people, we developed an instrument called the e-cone, which consists of a pressure sensitive matrix wrapped around a cone shaped base which allows visualisation of the grip force pattern in the form of an image. The original e-cone used a commercially available pressure sensor mat with a limited resolution which was not easy to attach to curved objects (like the e-cone) and was expensive. Therefore, we decided to develop our own pressure sensor mat using cheap pressure sensitive material and flexible printed circuit boards. The resulting sensor mat has a resolution of 64x64 sensor pixels, higher than any commercially available sensor, can more easily be attached to curved surfaces and allows acquisition of 15 fps across a wireless interface.