Impact sensing device and helmet incorporating the same
An impact sensing device including a plurality of accelerometers orthogonally oriented with respect to each other and attachable at a body location, each capable of producing signals indicative of impacts. An integrated circuit is configured to determine the magnitude and direction of the impacts based on the signals and operative to activate an indicator when the magnitude exceeds a first threshold based on the direction of the impact and when the magnitude exceeds a second threshold more than a selected number of times. A head injury coefficient is determined based on the magnitude and a duration of the impact, and the threshold level of acceleration is expressed in terms of a head injury coefficient value, which is determined by empirically correlating a head injury coefficient measured at the body location and a head injury coefficient measured at the center of mass of a human head resulting from an impact.
1. An impact sensing device, comprising:
a helmet wearable on a user's head;
at least one accelerometer capable of producing signals indicative of an impact;
an indicator;
an integrated circuit configured to receive the signals and activate the indicator when the signals exceed a selected first threshold level a selected number of times;
a chin guard sized and configured to receive the person's chin; the accelerometer and integrated circuit are contained in the chin guard;
a strap coupled with the chin guard; and
a button snap attached to the strap and removably connectable to the helmet, wherein the button snap includes contacts operative to activate the impact sensing device when connected to the helmet.
2. The impact sensing device of claim 1 , wherein the indicator is a visual indicator.
3. The impact sensing device of claim 1 , wherein the integrated circuit is configured to activate the indicator when the signal exceeds a selected second threshold level.
4. The impact sensing device of claim 1 , further comprising a soft inner cuff disposed in the chin guard.
5. The impact sensing device of claim 1 , said at least one accelerometer includes a plurality of accelerometers orthogonally oriented with respect to each other, and wherein the integrated circuit is configured to determine the magnitude and direction of the impact and activate the indicator when the magnitude exceeds a selected threshold based on the direction of the impact.