An alarm screen comprises a frame comprising a laser sensor, a processing unit, and a wireless transmitter embedded in a hollow interior. The frame comprises an opening for the laser sensor to project a laser beam outside of the alarm screen. The laser sensor projects the beam through the opening, makes a set of one or more measurements of a distance between the laser sensor and an object in a path of the laser beam, and sends the set of measurements to the processing unit. The processing unit is configured to compare the distance measurements received from the laser sensor with a threshold distance detect, and send one or more signals to the wireless transmitter when at least one of the distance measurements received from the laser sensor exceeds the threshold. The wireless transmitter is configured to receive signals from the processing unit and wirelessly transmit the signals.

Abeam detector apparatus (1) comprising: beam emitter apparatus (2); reflector apparatus (3), locatable across a volume to be monitored; and beam receiver apparatus (4). The beam emitter apparatus (2) is capable of creating a first linearly polarised beam of light of first linear polarisation and directing said first linearly polarised beam of light towards the reflector apparatus. The reflector apparatus (3) is capable of either: receiving the first linearly polarised beam of light and modifying such light into a beam having circular polarisation, elliptical polarisation or being unpolarised, and reflecting said circularly polarised, elliptically polarised or unpolarised beam of light towards the beam receiver apparatus; OR receiving the first linearly polarised beam of light and reflecting such light towards the beam receiver, and modifying such light into a beam having circular polarisation, elliptical polarisation or being unpolarised. The beam receiver apparatus (4) is capable of receiving said circularly polarised, elliptically polarised or unpolarised light and creating therefrom a second linearly polarised beam of light, in which the first and second linearly polarised beams of light have different polarisation.

Abeam detector apparatus (1) comprising: beam emitter apparatus (2); reflector apparatus (3), locatable across a volume to be monitored; and beam receiver apparatus (4). The beam emitter apparatus (2) is capable of creating a first linearly polarised beam of light of first linear polarisation and directing said first linearly polarised beam of light towards the reflector apparatus. The reflector apparatus (3) is capable of either: receiving the first linearly polarised beam of light and modifying such light into a beam having circular polarisation, elliptical polarisation or being unpolarised, and reflecting said circularly polarised, elliptically polarised or unpolarised beam of light towards the beam receiver apparatus; OR receiving the first linearly polarised beam of light and reflecting such light towards the beam receiver, and modifying such light into a beam having circular polarisation, elliptical polarisation or being unpolarised. The beam receiver apparatus (4) is capable of receiving said circularly polarised, elliptically polarised or unpolarised light and creating therefrom a second linearly polarised beam of light, in which the first and second linearly polarised beams of light have different polarisation.

A sensor unit comprising; a magnetic sensor adapted to detect a magnetic field; a light source adapted to transmit a radiation having a signature; a reflecting member for reflecting radiation emitted by the light source; a radiation sensor adapted to detect radiation reflected by the reflecting member; a controller adapted to generate a signal indicative of a security breach when the magnetic field is detected by the magnetic sensor and the signature is not identified in the radiation received by the radiation sensor.

Optical data transceiver is used to illuminate a secured space with an optical data signal which has been modulated to contain a first data sequence. One or more retroreflected optical data signals are received at the optical data transceiver from reflector elements disposed in the secured space. The retroreflected optical data signals are authenticated and a security event notification is selectively communicated to an enterprise security management controller if a variation occurs in regard to at least one retroreflected optical beam condition. The variation can involve a disruption of the optical beam and/or a displacement of the optical beam.

Optical data transceiver is used to illuminate a secured space with an optical data signal which has been modulated to contain a first data sequence. One or more retroreflected optical data signals are received at the optical data transceiver from reflector elements disposed in the secured space. The retroreflected optical data signals are authenticated and a security event notification is selectively communicated to an enterprise security management controller if a variation occurs in regard to at least one retroreflected optical beam condition. The variation can involve a disruption of the optical beam and/or a displacement of the optical beam.

A system for the surveillance of terrain and the detection of intrusions over a plane extending into that terrain. A curtain array of light beams is projected along the plane and reflections from the terrain are detected by a sensor array essentially spatially coincident with the array of light sources. The times of flight of the beams are determined, and these characterize the form of the terrain being surveilled. The initial background reflection pattern is acquired and stored by the system. A sudden change in this detected background pattern can be defined as arising from an unexpected reflection, indicative of an intrusion. Signal processing systems are described utilizing modulated laser beams and detection at a frequency at least twice that of the modulation, such that reflected signals arising from the ON and the OFF periods of the laser modulation can be subtracted to eliminate the background signals.

A system for the surveillance of terrain and the detection of intrusions over a plane extending into that terrain. A curtain array of light beams is projected along the plane and reflections from the terrain are detected by a sensor array essentially spatially coincident with the array of light sources. The times of flight of the beams are determined, and these characterize the form of the terrain being surveilled. The initial background reflection pattern is acquired and stored by the system. A sudden change in this detected background pattern can be defined as arising from an unexpected reflection, indicative of an intrusion. Signal processing systems are described utilizing modulated laser beams and detection at a frequency at least twice that of the modulation, such that reflected signals arising from the ON and the OFF periods of the laser modulation can be subtracted to eliminate the background signals.

An anti-intrusion device simulates the sound of a round being chambered in a pump shotgun using metal parts which strike one another. A striker carriage is movably disposed in a sound box for moving between first and second positions to engage metal striker plates and metal striker tabs against sound plates to simulate the chambering sound. A mangle drive assembly is mounted atop the sound box for moving the striker carriage between a forward position and a rearward position, powered by a stepper motor which is actuated to rotate a controlled axial displacement when a trigger mechanism is tripped. Preferably, the trigger mechanism is provided by a light mean sensor in which the light beam is broker by an intruder passing a selected entry point.

An alarm screen comprises a frame comprising a laser sensor, a processing unit, and a wireless transmitter embedded in a hollow interior. The frame comprises an opening for the laser sensor to project a laser beam outside of the alarm screen. The laser sensor projects the beam through the opening, makes a set of one or more measurements of a distance between the laser sensor and an object in a path of the laser beam, and sends the set of measurements to the processing unit. The processing unit is configured to compare the distance measurements received from the laser sensor with a threshold distance detect, and send one or more signals to the wireless transmitter when at least one of the distance measurements received from the laser sensor exceeds the threshold. The wireless transmitter is configured to receive signals from the processing unit and wirelessly transmit the signals.