Sound based fire alarm system and method
View Patent ↗Stovetop fires are among the more prevalent of resident fire hazards and smoke detectors are among the most prevalent and economical forms of residential fire alarms. Automatic stovetop fire extinguishers can prevent property damage and even personal injury; however, these stovetop fire extinguishers may also limit smoke emissions and the subsequent detection of smoke. While an initial fire may be efficiently subdued by an automatic stovetop fire extinguisher, it is often desirable to alert present and future occupants of a fire hazardous condition. A sound based fire alarm system and method are described herein, which detects a sound burst emitted upon deployment of an automatic stovetop fire extinguisher and triggers a continuous fire alarm to alert occupants of a potentially fire hazardous condition. Alarm signals can be audible, visual, or both. The system may be a stand alone system and use battery power for affordability and ease of installation. The method described herein enables the ready and automatic extinguishment of a stovetop fire, while alerting those in the surrounding area or those in adjacent dwellings of a fire situation.
1. A sound based fire alarm, the system comprising:
a self contained automatic stovetop fire extinguisher which emits a audible signal upon activation;
a sound burst sensor which detects audible signals and outputs a sense signal to a sensor circuitry;
wherein, the sensory circuitry processes received sensed signals and outputs processed sensed signals to a control circuitry;
wherein, the control circuitry receives processed sensed signals from the sensor circuitry, determines activation of the self contained automatic stovetop fire extinguisher, and outputs a trigger signal to an alarm system when activation of the self contained automatic stovetop fire extinguisher is determined; and
wherein, the alarm system comprises an alarm circuitry and an alarm device, and
wherein, when the alarm circuitry receives the trigger signal from the control circuitry, the alarm device provides a continuous fire alarm;
wherein, the sensory circuitry filters received sensed signal with a 2.5 kHz to 5.0 kHz band pass filter and outputs filtered sensed signals to the control circuitry;
wherein, the control circuitry comprises:
a digital signal processor which calculates a power spectral density via a fast fourier transform on a received sensed sound burst signal; and
an integrator which integrates the power spectral density signal over 3.0 kHz to 4.0 kHz; and wherein the control circuitry compares the integrated signal to a 120 decibel value and outputs a trigger signal to the alarm circuitry when the integrated signal exceeds 120 decibels.