Patent ID: 8253571

Claim:
An apparatus for sensing impact of a body on a strip located on a support, comprising: a strip of material presenting piezoelectric characteristics, applicable to the support in a region to be monitored, at least one continuous tape made of conductive material and associated with said strip in a manner parallel to it, a conditioning device connected to said tape to condition an electric signal generated by the impact of said body on said strip, a signal sensing device for sensing said conditioned electric signal, a signaling device for indicating the sensed signal, wherein a signal recognition device is associated with the signal sensing device, wherein the signal recognition device comprises a circuit for comparing characteristics of said conditioned electric signal with characteristics of a signal typical of an impact of said body under observation on said strip, wherein the circuit comprises: means for determining a maximum negative value (V min ) of said conditioned electric signal provided by the impact of said body on said strip, means for determining a prefixed percentage (p.V min ) of said maximum negative value (V min ), means for determining a difference (ΔV) between said maximum negative value V min and said prefixed percentage value (p.V min ) and a time difference (Δt) between the moments associated with said values (V min , p.V min ), means for determining a ratio (ΔV/Δt) of said difference (ΔV) to said time difference (Δt), means for comparing said ratio (ΔV/Δt) with a prefixed threshold value (V s ′), and means for feeding a signal to said signaling device when said ratio (ΔV/Δt) exceeding said threshold value (V s ′).