1. A system comprising: m sensors, m being a positive integer, each for detecting intrusion into an area and each having an output, each said output having an on state and an off state; computing means connected to said outputs of each of said m sensors for determining whether or not each of said outputs is in said on state, for assigning a weighting factor to each said output that is in said on state, for calculating the sum of all said weighting factors, for comparing said sum to a reference and for providing an output when said sum exceeds said reference; n sensors, n being an integer, having an on state and an off state, for detecting intrusion into said area, operably coupled to said computing means for receiving said computing means output and being activated to said on state thereby.