A security sensor (S i) for detecting intrusion events and/or environmental events along a perimeter, the sensor comprising a container body and a signal acquisition and processing module housed in the container body, wherein the signal acquisition and processing module comprises: - a piezoelectric transducer adapted and configured to convert a mechanical stress to which the piezoelectric transducer is subjected into a first electrical signal (Sp); - an accelerometric transducer, preferably a MEMS accelerometric transducer, adapted and configured to convert an acceleration to which the accelerometric transducer is subjected into a second electrical signal (s a); - a processing unit operatively connected to the piezoelectric transducer and to the accelerometric transducer for receiving the first electrical signal (s p) and the second electrical signal (s a); wherein the processing unit is adapted and configured to: - process the first electrical signal (s p) for obtaining a first flow of digital samples D(s p) having digital values correlated with an amplitude measurement of the first electrical signal (Sp); - process the second electrical signal (s a) for obtaining a second flow of digital samples D(s a) having digital values correlated with an amplitude measurement of the second electrical signal (s a); - process the first flow of digital samples D(s p) and the second flow of digital samples D(s a) for obtaining at least one processed flow of digital samples D j ( s p, s a) therefrom, wherein each digital sample of the processed flow of digital samples D j ( s p, s a) has a digital value obtained according to a respective digital sample of the first flow of digital samples D(s p) and a respective digital sample of the second flow of digital samples D(s a) by means of a calculation function F which applies a weighting coefficient to at least one of the respective digital sample of the first flow of digital samples D(s p) and the respective digital sample of the second flow of digital samples D(s a); - detect an intrusion event and/or an environmental event according to the analysis of the processed flow of digital samples D j ( s p, s a). - a piezoelectric transducer adapted and configured to convert a mechanical stress to which the piezoelectric transducer is subjected into a first electrical signal (Sp); - an accelerometric transducer, preferably a MEMS accelerometric transducer, adapted and configured to convert an acceleration to which the accelerometric transducer is subjected into a second electrical signal (s a); - a processing unit operatively connected to the piezoelectric transducer and to the accelerometric transducer for receiving the first electrical signal (s p) and the second electrical signal (s a); - process the first electrical signal (s p) for obtaining a first flow of digital samples D(s p) having digital values correlated with an amplitude measurement of the first electrical signal (Sp); - process the second electrical signal (s a) for obtaining a second flow of digital samples D(s a) having digital values correlated with an amplitude measurement of the second electrical signal (s a); - process the first flow of digital samples D(s p) and the second flow of digital samples D(s a) for obtaining at least one processed flow of digital samples D j ( s p, s a) therefrom, wherein each digital sample of the processed flow of digital samples D j ( s p, s a) has a digital value obtained according to a respective digital sample of the first flow of digital samples D(s p) and a respective digital sample of the second flow of digital samples D(s a) by means of a calculation function F which applies a weighting coefficient to at least one of the respective digital sample of the first flow of digital samples D(s p) and the respective digital sample of the second flow of digital samples D(s a); - detect an intrusion event and/or an environmental event according to the analysis of the processed flow of digital samples D j ( s p, s a).