US Patent 9943128 Helmet impact monitoring system

An impact sensing system includes a first impact sensor having a flexible dielectric layer, a first printed electrode on a first side of the layer, and a second printed electrode on a second side of the layer. The second printed electrode overlies and is moveable toward and away from the first electrode by deformation of the flexible dielectric layer. Further, the layer maintains a capacitance between to the first electrode and the second electrode that changes with a movement of the second electrode toward or away from the first electrode. The system further includes a first readout circuit electronically coupled with the first and second electrodes to measure a change in the capacitance and output a corresponding voltage.