Patent ID: 8120472

Claim:
A portable alarm device for protecting a car against theft or burglary, wherein the portable alarm device is adapted to be placed onto a surface, such that the portable alarm device functions properly regardless of an orientation of the portable alarm device on the surface, wherein the portable alarm device comprises: a housing having at least one opening in at least one of housing walls to provide an air path to one of a microphone and a sound vibration sensor located within the housing, the microphone and the sound vibration sensor detecting infrasound signals within a frequency range of 0.1-15 Hz; electrical circuitry disposed within the housing, the electrical circuitry processing signals from at least one of the microphone and the sound vibration sensor and emitting an alarm signal based on an automatic determination that a detected event is abnormal; and a power supply embedded in the housing, and wherein the housing includes means ensuring a distance between the at least one opening and a support surface of the car, so as to ensure a presence of an unobstructed air path into the at least one opening regardless of the orientation of the portable alarm device on the support surface when the housing is placed to rest onto the support surface within the car.