Omni-directional crash sensor

Abstract

A stress wave sensor comprising a piezoelectric film and means therein for connection to sensor electronics. The piezoelectric film preferably comprises polyvinylidene fluoride. Also a stress wave sensor system and methods employing one or more such stress wave sensors, preferably attached to a vehicle transparent component, most preferably to the vehicle windshield.

1 . A stress wave sensor comprising a piezoelectric film and means therein for connection to sensor electronics. 
   
   
       2 - 3 . (canceled) 
   
   
       4 . An impact detection system comprising a plurality of stress wave sensors each comprising a piezoelectric film, said system optionally comprising one or more accelerometers, wherein each stress wave sensor is attached to a vehicle skin, structural, or transparent component, and preferably to a transparent component. 
   
   
       5 . The impact detection system of  claim 4 , wherein each stress wave sensor comprises polyvinylidene fluoride. 
   
   
       6 - 8 . (canceled) 
   
   
       9 . A method of filtering crash events from non-crash events by comparing a response of one or more piezoelectric film sensors located on a transparent portion of a vehicle to a response of one or more piezoelectric film sensors not located on a transparency portion, and optionally employing the steps of collecting output from the plurality of sensors; and analyzing one or more of the group consisting of: one or both of amplitude and rise time of each sensor's output; each sensor's output in a plurality of frequency bands, preferably from at least bands at approximately 1 kHz-2.5 kHz and 5 kHz-20 kHz; and time differentiated outputs of the sensors. 
   
   
       10 . A vehicle windshield comprising a crash sensing system comprising one or more piezoelectric stress wave sensors positioned in or on the vehicle windshield. 
   
   
       11 - 15 . (canceled)