Abstract: A dual powered flashlight responsive to an audible smoke detector alarm includes a sound sensor for sensing an audible smoke detector alarm and producing an electrical alarm signal in response; a frequency-sensitive amplifier amplifying the electrical alarm signal but not other signals; an integrator for integrating the electrical alarm signal amplified by the frequency-sensitive amplifier and for generating a trigger signal only when the integrated signal exceeds a threshold; a lamp; a battery connector for receiving a battery for providing current for illuminating the lamp; a power supply including a mains connector connectable to electrical power lines and powering the frequency-sensitive amplifier and the integrator; and a switch receiving the trigger signal and a power supply signal from the power supply for connecting the lamp to the battery in response to at least one of a trigger signal and absence of application of electrical power to the mains connector.

Abstract: An earth-tremor-responsive light contained in a main housing is described having a back member for mounting against a vertical wall and a light transmitting front cover; a stand-by battery; a light emitter; electrical circuit elements connecting the battery to the light emitter through an inertial switch which is actuated by acceleration resulting from earth tremors, the inertial switch including a switch chamber having a generally horizontal shallow upwardly-facing conical surface with a central apex at a lower point thereof; a spherical ball urged by gravity to rest in a central disposition on the conical surface; a vertical shaft projecting externally of the main housing and disposed in the chamber aligned with the central apex and above the ball, the shaft being guided for vertical movement in the chamber and having a lower end resting on top of the ball; a spring urging the shaft downwardly to a set position against the ball at rest in its central disposition, whereby a peak acceleration resulting from a