Laboratory Evaluation of Wireless Head Impact Sensor

Interest in head impacts in sport has driven the development of technology for the purpose of impact measurement. Wireless, small form factor impacts sensors have been designed for use in both helmeted and non-helmeted sports. Performance of a wireless head impact sensor was assessed under laboratory conditions using a Hybrid III headform and neck. The Hybrid III assembly was mounted on a low friction sled and impacted with three sports balls at two locations, and from three directions. The ball was projected with a pneumatic cannon at speeds ranging from 10 to 31m/s. The wireless sensor was mounted on the exterior of the headform in the same location and orientation that would be used during play. Wireless sensor estimates of linear and angular acceleration at the headform center of mass were compared to measures obtained from linear accelerometers and angular rate sensors mounted at the headform center of mass. As ball stiffness increased the relative power of frequency components in the acceleration signal above the wireless sensor Nyquist frequency increased, the contact duration decreased and accuracy of the wireless sensor decreased.