Dual powered, smoke detector activated flashlight

A dual powered flashlight responsive to an audible smoke detector alarm comprising:

• a sound sensor for sensing audible signals, including an audible smoke detector alarm, and producing electrical signals in response, the electrical signals including an electrical alarm signal produced in response to an audible smoke detector alarm;
• a frequency-sensitive amplifier receiving the electrical signals and selectively amplifying the electrical alarm signal in the electrical signals produced by the sound sensor;
• an integrator receiving the electrical alarm signal from and amplified by the frequency-sensitive amplifier for integrating the electrical alarm signal amplified by the frequency-sensitive amplifier to produce an integrated signal 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 normally closed switch connecting the lamp to the battery when the normally closed switch is closed, the normally closed switch being opened while the mains connector is supplied with electrical power unless a trigger signal is applied to the normally closed switch by the integrator, whereby battery life is maximized.