Patent ID: 6846994

Claim:
A system for delaying activation of a battery-powered electrical device, intended to operate remotely in an environment in which a pH value changes from a first value to a second value, comprising: a housing defining an interior space and having an exterior surface; a magnetic field source proximally associated with said housing, said magnetic field source being separable from said housing upon exposure to an environment having a pH value equal to said second value; a normally closed electrical circuit disposed in said housing; said circuit having a battery connected in series with an electrically powered device, whereby said electrically powered device is powered by said battery upon closing of said circuit; said circuit having switch means sensitive to the presence of a magnetic field associated with said magnetic field source; said switch means operable to open said circuit in the presence of said magnetic field and to close said circuit in the absence of said magnetic field; whereby when said housing encounters an environment having a pH value equal to said second value, said magnetic field source separates from said housing and said circuit closes, powering said electrically powered device.