The system incorporates wire deflection, taut wire detection for perimeter security applications. Generally, the system of the invention provides intrusion detection by an internal mechanism. The internal mechanism can detect wire deflection in any direction. In turn, given a sufficient amount of wire deflection, a security system is signaled. However, the force required to sufficiently deflect the wires is high enough so as to minimize nuisance alarms. The internal mechanism is generally held within a structure so that it is protected from tampering. As such, the internal mechanism is also kept separate from the wire array so that it is protected from attempts by an intruder to isolate the wire array.