Fence with security wires fastened to posts via sensors
AssigneeKTV-Systemtechnik GmbH
InventorManfred Sticksel
Life of this patent
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Abstract
A fence having security wires fastened to posts via sensors and having an electronic evaluation circuit connected to the sensors, which releases an alarm signal when one of the sensors signals a contact of the security wire which is connected to it. Each sensor has a housing fastened to a post, a holder connected to a security wire and a transformer placed between housing and holder, which produces a signal which is approximately proportional to the position of the holder. An alarm signal is generated when one or only a few security wires move slowly, yet such slow movements are ignored when caused by environmental factors. A highly reliable security fence is thus obtained.
Claims12
An intrusion detection system comprising:
- a fence with security wires fastened to posts via sensors,
- each sensor including a transducer for generating a signal approximately proportional to the tension in an associated wire,
- an electronic detection circuit to which the transducers are connected and which comprises:
- a switching system which connects the transducers in sequence in a scanning cycle to a detector to detect the signal amplitude generated by each transducer,
- a circuit for generating a mean value of the signal amplitudes detected within a scanning cycle,
- a comparator for comparing the signal amplitude of each transducer with the mean value and for presetting an alarm signal when the difference between a signal amplitude and the mean value exceeds a first threshold,
- an identification circuit to identify transducers which generate signal amplitudes for which an alarm signal was preset,
- said comparator including means for comparing said signal amplitudes of each identified transducer for which an alarm signal was preset with the signal amplitude of said each identified transducer of the preceding scanning cycle and for generating an alarm signal when the difference between the compared signal amplitudes exceeds a second threshold.
Dependencies are inferred from the claim text.