For some time now, Securiton has been using ultrasound to protect rooms – the latest innovation in the field of intrusion protection. As soon as a body moves in a room protected in this way, the field covered by the sound waves is disturbed as the sound waves reflected by the intruding body reach the receiver at a different frequency. The controller then detects a discrepancy when comparing the transmitted and received frequencies and triggers the alarm.
The new safety system is based on the following principle: A transmitter installed in the room to be protected continuously emits ultrasonic waves that are not perceptible to humans. As with a loudspeaker, electrical vibrations are converted into sound waves. These meet a receiver located in the same room. The sound waves are then converted back into electrical vibrations. The transmitted and received frequencies are compared with each other in the controller installed in the control panel. If these match, this means that the field covered by the sound waves is unchanged, i.e. there is no disturbance.
As soon as a body moves in a room protected in this way, the field covered by the sound waves is disturbed as the sound waves reflected by the invading body reach the receiver at a different frequency. The controller then detects a discrepancy when comparing the transmitted and received frequencies and triggers the alarm.
In order to prevent the alarm from being triggered by even the slightest changes in the monitored room – caused by draughts, small vibrations or a mouse, for example – the frequency deviation must assume a certain intensity, whereby the sensitivity of the system can be adapted to the conditions. An alarm can not only be triggered by a solid body, but also by an excessive flow of heat, meaning an ultrasonic system can also serve as a fire alarm system.
As with any alarm, transmission can either be made silently to an alarm receiving centre via Telealarm or Signaphon, or a siren can be actuated at the same time. The siren is often accompanied by a strong light source. Like all Securiton systems, the ultrasonic system is also protected against sabotage. Compared to the previous mechanical intrusion protection systems, the ultrasonic system has the advantage that no major installation work is required. Until now, such comprehensive room protection has only been achieved by affixing surface protection to the floor, hallway and all walls, which is usually only possible in new buildings. Ultrasonic systems are therefore particularly suitable for installation in existing rooms, especially since the transmitter and receiver are only half the size of grapefruit and can be installed in the room without significantly disturbing its look.