JP2011508915A - Warning device and method - Google Patents

Abstract

  The warning device and method includes an elongated cavity and a speaker coupled to the first portion of the cavity, and the sound generated by the speaker is directed through the cavity to provide an audible sound. Yes. These cavities and speakers are configured and sized to provide substantially the audible sound at an anti-resonant frequency that is between the peaks of the first and second resonant frequencies relative to the system impedance of the response spectrum for the speakers and the cavity. Is done.

Description

  The present disclosure relates to warning devices and methods, and more particularly to high performance speaker alarms with improved audibility that are lightweight, compact and low cost.

  Common fire alarms, especially household fire alarms, are small devices designed to warn people if a fire or other harmful condition such as smoke or high levels of carbon monoxide occurs. is there. Conventional designs include a cylindrical alarm with a sensor and speaker on the front. This design is typically about 10 to 15 cm thick, even if this can be altered with the design. The acoustic generator or speaker of these devices is usually a piezoelectric disk because it is compact and inexpensive. The general acoustic response of a conventional fire alarm / smoke detector device is shown in FIG.

  Referring to FIG. 1, a normalized frequency spectrum is shown, where the sound pressure level SPL (dB) versus frequency (Hz) is plotted. Notice that the peak response is just above 3 kHz. One problem with conventional alarm sound generators is that the main frequency is typically about 3 kHz, which is high enough to be easily attenuated by walls and doors. At this frequency, the signal is not enough for a sleeping person to listen. This problem is complicated if the fire alarm / smoke detector is not in the bedroom or in the area where the person is sleeping, or if the fire alarm / smoke detector is located on another floor of the house.

  Many governments require that the sound level at the bedside for smoke detectors / fire alarms should be at least between 70 and 75 dB. Despite this requirement, the problem becomes more severe as the minimum audible value rises, which is common for people with hearing impairments or as they age.

  D. Bruck and M. Ball (Bruck), "Sleep and fire: Who is at risk and can the risk be reduced?", Proceedings of the 8th International Symposium of the International Association for Fire Safety Science, Beijing, Sept 2005 Discloses increasing risk factors for fire safety. The following is a quote from Bruck, and the reference symbols shown as numbers between the parentheses are reference symbols in Bruck's book, not from this document.

“However, if other risk factors are present, it is assumed that sleep is a significant risk for burning. Smoke alarm and sleep studies have shown us that an important“ sleep maintenance ”risk factor is
・ High level of background noise ・ Deep sleep ・ Lack of sleep ・ Children ・ Sleep medicine is effective ・ Alcohol dependence (usually 0.05 BAC (blood alcohol concentration))
• Hearing impairments (for high pitch signals, including many people over 60) These risk factors can be attributed to the presence of increased sleep by a fire signal or warning signal on any given night Since it means getting an opportunity, the problem of which type of alarm signal is optimal must be addressed. Fortunately, studies comparing the wake-up efficiency of different alarms have reached the same conclusion. Evidence from studies with infants, non-drunk adults and drunken adults suggests that such people are more likely to notice with a small amount of low-frequency signals than with high-frequency signals. Both the low pitch T-3 beep signal and female voice alerts elicit behavioral responses in non-drunk adults in an amount about 13 dBA less than high pitch alerts [10]. Similarly, the likelihood that 6 to 10 years of age will notice a low pitch T-3 or voice alarm is approximately twice as likely as that of the same loud volume and high pitch alarm [27]. The critical optimal frequency is the same pitch range as a human voice (2500 Hz or lower), even though some studies on sleep neonatal responses [35] suggested that low frequencies (120-150 Hz) were optimal. It is possible that the frequency is within. People representing deaf people claim sound [36] between 100 and 700 Hz. "

  Conventional acoustic alarms do not provide an optimal amplitude or frequency response due to their size and cost requirements. Such conventional designs mainly use a speaker mounted in a horn that utilizes a piezoelectric disk with the above-mentioned drawbacks or is subject to the same limitations (folded). Accordingly, there is a need for improved alarm devices.

  In accordance with the present principles, an alarm device is provided that includes an improved response that is less damped than conventional designs and that provides a cost-effective, lightweight, compact design. This improved device uses multi-tone signals, which can be emitted simultaneously and efficiently from a compact device. In one embodiment, a conventional piezoelectric disk type sound generator is replaced with a small but very efficient speaker. This small speaker can be mounted in a tube and can generate more than one sound at the same time. In another embodiment, the speaker is used to provide a voice message. One advantage of doing this is that it provides a low-cost, compact and lightweight alarm with improved audibility for the hearing impaired or in difficult conditions such as wall attenuation.

  The alarm device and method includes an elongated cavity and a speaker coupled to the first end of the cavity, wherein sound generated by the speaker is directed through the cavity to provide an audible sound. It is done. These cavities and speakers are configured and sized to provide substantially audible sound at an anti-resonant frequency that lies between the peaks of the first and second resonant frequencies relative to the system impedance of the response spectrum for the speakers and cavities. The

  The detector device includes a trigger device configured to trigger an alarm signal according to the condition. The warning device includes a tube and a speaker coupled to the first end of the tube, wherein the sound generated by the speaker is directed through the tube to provide an audible sound; The tubes and speakers are configured and sized to provide a substantially audible sound at an anti-resonant frequency that is between the peaks of the first and second resonant frequencies relative to the system impedance of the response spectrum for the speakers and tubes. A controller is coupled to the trigger device and is configured to activate the warning device in accordance with the warning signal.

  A method for sounding an alarm includes providing an alert device including an elongated cavity and a speaker coupled to a first end of the cavity, wherein the sound generated by the speaker is for providing an audible sound. , Directed through this cavity. The cavities and speakers are configured to provide substantially audible sound at an anti-resonant frequency that lies between the peaks of the first and second resonant frequencies for the system impedance of the response spectrum for the speakers and cavities. .

  These and other objects, features and advantages of the present disclosure will be apparent from the following detailed description of exemplary embodiments of the invention, which will be read according to the accompanying drawings.

The figure which shows the frequency response spectrum for the conventional fire alarm piezoelectric disk speakers. 1 is a cross-sectional view of a warning / alarm device having a bandpass housing according to an embodiment. FIG. 3 is a cross-sectional view of a warning / alarm device having a reflective housing according to another embodiment. 1 is a cross-sectional view of a prototype and a warning / alarm device to be tested, according to an embodiment. FIG. 3 is a plot of impedance versus frequency showing anti-resonance frequency according to one embodiment. FIG. 5 is a plot of fundamental harmonic sound pressure level (dB) versus frequency for the apparatus of FIG. 1 is a schematic diagram illustrating a system that generates a warning / alarm according to a trigger event. FIG. 6 is a flowchart of a method for sounding an alarm according to an embodiment.

  The present disclosure discloses warning / alarm devices, in particular home alarm devices for smoke detectors, fire alarms, burglar alarms or other warning systems. Although the present embodiment will be described with respect to a compact alarm device, this disclosure teaches a wide range of any components used to produce sound waves, such as loudspeaker (PA) devices, car horns, etc. It should be understood that it also applies to sirens and the like. The embodiments described herein are preferably used for home use so as to provide the benefit of reducing acoustic attenuation in the home environment. However, as mentioned above, home use is one application. Other applications may include air horns, signaling devices or the like used in any environment.

  The alarm device may be made from a number of different materials, such as metal (eg steel, brass), wood, plastic or any other suitable material. In one embodiment, plastic is preferred for manufacturing the tube of the device because it is cost effective, is easily molded to form and is environmentally resistant to degradation.

  It should also be understood that embodiments of the alarm device are adapted to include electronic components, software modules and a plurality of different power sources. These components may be mounted in the alarm device or on other components. The electrical element is programmable and may include a number of different sensor types. The elements depicted in the drawings may be implemented in various combinations and may provide functions that are combined in a single element or multiple elements.

  Referring to the drawings in which like numerals indicate the same or similar elements, and initially referring to FIG. 2, an alarm device 100 is shown in accordance with an illustrative embodiment. The apparatus 100 includes a first chamber 104 that forms a bandpass housing that is configured to receive a speaker 102. The speaker 102 is preferably small enough to attach directly to the inner diameter of the first chamber 104. Chamber 104 is separated into two volumes V0 and V1. Volume V0 is bounded by the side wall of chamber 104, rear wall 108 and speaker 102 or any plate 110 to which the speaker is attached. The plate 110 may be used to accommodate another speaker 102 for placement inside the chamber 104. Volume V1 is in fluid and acoustic communication with open cavity 106. The cavity 106 may include a tube or a pipe, and may include an internal cross section Sp that may be any shape. The length of the cavity 106 is Lp.

  In an alternative embodiment as depicted in FIG. 3, the apparatus 200 includes a speaker 202 mounted in a chamber 204. Chamber 204 forms a reflective housing with a long port or pipe 206. The separated volume V0 has been removed. The pipe or tube 206 includes an internal cross section Sp that can be of any shape. This is the length Lp of the cavity 206.

  Referring to FIG. 4, to obtain high efficiency, an alternative embodiment may attach the speaker / device 302 to the tube 306 such that the diameter D1 of the device 302 is less than the diameter Dp of the tube 306. In this case, the volume V1 can be deleted or minimized by the desired frequency response.

  2, 3 and 4, the pipe 106, 206 or 306 may be any shape of elongated cavity. The chamber, speaker and cavity are designed to have high efficiency, which is achieved because the tube cavity acts as an acoustic resonator. The system needs to have the low attenuation (high Q, see peak 502 in FIG. 6) that is achieved when the wall of the tube is smooth and the tube is not too thin, i.e. in diameter or thickness. It is preferably larger than 2 cm. In certain embodiments, parameters are selected to optimize performance. In one example, the speaker's electrical impedance at the operating frequency Fb is approximately twice the direct current (DC) impedance.

  If a direct current (DC = zero frequency) resistance is measured for the system (speaker mounted in a cavity), this is called a voice coil DC resistance (Z (DC)).

  When measuring the electrical resistance at the operating frequency (in a speaker mounted in a cavity), this is called Z (fwork = Fb), where Z (fwork) is about 2 * Z (DC). Required, which means that the speaker and housing fit together and are optimally tuned. This is hereinafter referred to as tuning criteria. Other adjustment criteria may be used as well. For example, the electrical impedance at the operating frequency is preferably about twice the DC impedance. However, in other embodiments, the electrical impedance at the lowest operating frequency is between about 1 and 3.5 times the DC impedance, preferably between about 1.75 and about 2.25 times. Equal to the frequency.

  Referring to FIG. 5, the specific frequency fwork is selected so as to substantially match the antiresonance frequency indicated as Fb. This anti-resonance frequency Fb is the frequency at which the electrical input impedance curve (Z (Ω)) reaches a minimum between the first two impedance peaks 402 and 404 (seen on the left side of the frequency scale). These impedance peaks 402 and 404 correspond to the natural or resonant frequency of the system including chamber 104 (204) and tube 106 (206), or the natural frequency of speaker 302 and tube 306 in FIG. These natural frequencies f1 and f2 are selected by selecting the characteristics of the loudspeaker (drive device) and the dimensions of the chamber and pipe.

  Fb is then selected or measured and used as the operating frequency of the device. The advantage of choosing Fb is that a low cost, compact and lightweight alarm with improved audibility is achieved for hearing impairment or for use in difficult conditions such as being attenuated greatly by the walls. This is achieved because it is at least a lower operating frequency than conventional devices. In addition, multiple sounds can be achieved, for example, by using speakers such as those found on radios or other devices. In some embodiments, a speaker may provide more than one sound simultaneously.

  Referring to FIGS. 5 and 6, the chamber, speaker, and elongated cavity (106, 206, and / or 306 in FIGS. 2, 3, and 4, respectively) form a resonant system. This elongated shaped cavity includes a tube having an annular (elliptical or circular cross section), rectangular (rectangular or square cross section) or any other shaped cross section. This structure preferably substantially provides audible sound at an anti-resonant frequency that is between the first and second resonant frequency peaks of the system impedance (FIG. 5). In other words, the first peak (502) in FIG. 6 coincides with the local minimum (at frequency Fb) between the peaks 402 and 404 in FIG. Note that the vertical axis in FIG. 6 is SPL (dB), and the vertical axis in FIG. 5 is the magnitude of electrical impedance (Ω).

  The tube dimensions and speaker size are preferably chosen such that at the anti-resonance frequency Fb, the electrical impedance of the system is twice the DC impedance, even if other criteria are used. The frequency of the alarm sound can be changed so that the subject can hear it optimally. In one embodiment, the length of the tube or cavity (106, 206 or 306) is adjusted so that the adjustment criteria are met. This is accomplished, for example, by creating a cylindrical telescope (eg, a car antenna) whose length is optimized and adjusted.

  In another embodiment, the anti-resonance frequency is adjusted by adjusting the properties of the pipe or chamber. The adjustment is made to increase the chance of hearing a specific sound. For example, if the smoke alarm user is deaf, the alarm is adjusted to a frequency range that is particularly audible to the user.

  Referring again to FIG. 4, a small speaker 302 is mounted on / in the tube 306. The tube 306 may be bent or folded in any direction. The prototype acoustic response is shown in FIG. For illustration purposes, the tube diameter Dp and length Lp are 3 cm and 15 cm, respectively, and the speaker diameter is 2.4 cm.

In the exemplary embodiment of FIG. 4, the following parameters are used to perform the test: For the speaker 302, R _E = 6.6Ω (DC resistance), R _M = 0.49Ns / m (mechanical resistance of the suspension device to which the speaker is attached), B1 = 2.56N / A (speaker power coefficient) S _l = 0.000452 m ² (speaker range), Dl = 0.024 m (speaker effective diameter), fs = 360 Hz (speaker resonance frequency) and ml = 0.00057 kg (speaker moving mass). For the system, Vl = 1 cm ³ (chamber volume), Lp = 15 cm (pipe or tube 306 length), Dp = 30 mm (tube 306 diameter). It should be understood that these parameters are for illustrative purposes and should not be considered limiting.

  Referring to FIG. 6, the prototype SPL illustrated in FIG. 4 using exemplary parameters is shown for various voltages relative to the fundamental frequency. These voltages 1V to 6V indicate the power supply voltage of the speaker, and this power supply voltage is preferably a DC power supply (eg by a battery). It should be noted that other power sources may be used, such as an AC power source, or a transformer may be used or power may be supplied directly to the speaker or its speaker control circuitry. The highest voltage provides the highest SPL for all plots. The operating frequency corresponds to the peak 502 in FIG. 6, which is preferably less than 1000 Hz, and in this example (eg prototype) is about 550 Hz.

  In the preferred embodiment, two or more sounds may be played simultaneously. These sounds preferably include frequencies that correspond to the peaks in FIG. 6 in order to obtain high audibility and attenuation. In other words, the resonance peaks 502, 504 and the peak with the higher frequency in FIG. 6 (on the right side of 504) are coincident for two or more sounds. In another embodiment, the speaker can be used to issue a voice message.

  These peaks in FIG. 6 are mainly determined by the speaker housing (including the tube) because it is better to adjust these sounds so that they are substantially below 1000 Hz. In one embodiment, sensing the system impedance (measuring the current through the speaker and the voltage across the speaker) and adjusting the frequency (by adjusting the cavity or speaker) to obtain the desired frequency. The sound can be adjusted automatically.

  There are two or more sounds that share the same peak or share at least one peak with another sound. For example, the first sound has at least peaks 502 and 504. This first sound is used together with a second sound that has both frequencies at the first peak (502) in FIG. 6, and the third sound is at the second peak (504) in FIG. With a frequency of These sounds are preferably shown simultaneously, and the sounds may alternate in order to obtain more attenuation.

  Referring to FIG. 7, an alarm device 600 is illustratively shown according to one application. Alarm device 600 may be a smoke detector, a fire alarm, a carbon monoxide detector, or any other device configured to sense a condition and provide an alarm. The device 600 includes a power source 608 that includes a battery or other known power source. The power supply 608 is turned on by a switch 610 or other device to initiate activity (eg, sense condition or activate speaker (LS) 614). One or more sensors 604 are preferably provided for sensing environmental conditions for operating the acoustic alarm device 620.

  The alarm device 602 may be manually operated by operating a switch (for example, the switch 610) according to the operation mode or application. For example, the device 600 may exceed the threshold value (stored in the memory 606) as measured by the sensor 604 (the processor / controller 612 performs the comparison). The alarm device 620 is used as a carbon monoxide detector that operates by supplying power to the speaker 614.

  Other events may be used to cause alarm device 620 to operate. For example, the alarm device 620 may be activated after a predetermined amount of time (eg, an alarm clock or a class bell). This alarm device can be used as an audible alarm and evacuation signal, or a personal alarm device in crime prevention devices (eg women carry this device in their bags), or bicycles, cars or other platforms (eg clocks) Radio, PDA, telephone ringtone generator, etc.). The processor / controller 612 supplies power and signals to the alarm device 620. Depending on the condition or triggered sensor 604, different sounds, sounds, or combinations thereof may be provided to the speaker 614. By using different frequencies or combinations for the system 600, such as for smoke, carbon monoxide, etc., the encoded message can be emitted. Other alarm mechanisms, such as light, may be used as well.

  The alarm device includes a chamber 616 and a tube 618 having features as described above in accordance with the present principles. Chamber 616 may be reduced to a small volume as depicted in FIG. Tube 618 preferably has small acoustic attenuation and may be curved or bent in any direction to conserve space or direct sound in a particular direction. Tube 618 may include an adjustment mechanism 622 for adjusting the output of the audible sound. The adjustment mechanism 622 adds mass to the system, shrinks the cross section of the tube 618, adds attenuation, and / or extends the length of the cavity 618 (eg, a telescope). Adjustments may be made manually using a mechanical device 624 such as a spring or screw acting on tube 618, or the adjustment is controlled based on user input or acoustic feedback from one of sensors 604. A processor may be used. Adjustments may be made to the power or output of the speaker in order to effect the change fed back by the user. For example, to determine the impedance, voltage and current measurements are made on the speakers and optimal adjustments are made.

  Referring to FIG. 8, a flowchart illustrating a method for sounding an alarm is shown in accordance with the present principles. At block 702, a warning device is provided that includes an elongated cavity and a speaker coupled to the first end of the cavity, and the sound generated by the speaker passes through the cavity to provide an audible sound. Directed. At block 704, the cavity and speaker provide the audible sound substantially at an anti-resonance frequency that is between the peaks of the first and second resonance frequencies for the system impedance of the response spectrum for the speaker and cavity. Composed. For example, the audible sound includes at least one of a plurality of sounds and voice messages. These plural sounds each include peaks of fundamental frequencies at substantially the same frequency. Configuring the cavity and speaker also includes configuring a chamber that houses the speaker. The electrical impedance provides an operating frequency equal to the anti-resonance frequency that is between about 1 and about 3.5 times the DC impedance. Configuring the system also includes making adjustments to the chambers, cavities and speakers to meet impedance or other criteria. This includes changing the characteristics of the system, for example using an adjustment mechanism (622) or using feedback to adjust the acoustic response. At block 706, an audible sound is generated by operating the speaker.

In interpreting the appended claims,
a) the term “comprising” does not exclude the presence of elements or actions other than those listed in a given claim;
b) The fact that an element is not expressed in plural does not exclude that there are plural elements.
c) any reference signs in the claims do not limit their scope;
d) Several “means” may be represented by the same item or configuration or function implemented in hardware or software,
e) Unless otherwise indicated, it does not mean that a special sequence of activities is required.

  Although preferred embodiments of alarm devices and methods (for purposes of illustration and not limitation) have been disclosed, it should be noted that modifications and changes may be made by those skilled in the art in view of the above teachings. It is to be understood that changes are made to the particular embodiments disclosed which are within the scope and intent of the embodiments disclosed herein, as outlined by the appended claims. Accordingly, the claims protected by the patent are set forth in the appended claims as set forth in detail, and where specifically required by patent law.

Claims (25)

An alarm device having an elongated cavity, and a speaker coupled to a first end of the elongated cavity, the sound generated by the speaker being directed through the cavity to provide an audible sound; The cavity and the speaker are configured to provide the audible sound substantially at an anti-resonance frequency that is between the peaks of the first and second resonance frequencies for a system impedance of a response spectrum for the speaker and the cavity, and Alarm device to be measured.   The apparatus of claim 1, wherein the speaker is attached to a chamber that is in acoustic communication with the cavity.   The apparatus of claim 1, wherein the speaker is attached to a chamber and divides the chamber into two volumes such that one volume is in acoustic communication with the cavity.   The apparatus of claim 1, wherein the alarm device is operated by one of a smoke detector, a fire alarm and a carbon monoxide detector.   The apparatus of claim 1, wherein the audible sound includes a plurality of sounds.   The apparatus of claim 1, wherein the plurality of sounds share at least one peak frequency.   The apparatus of claim 1, wherein the audible sound comprises a voice message.   The apparatus of claim 1, wherein the alarm device includes an electrical impedance at a minimum operating frequency equal to an anti-resonance frequency that is between about 1 and about 3.5 times the DC impedance.   The apparatus of claim 1, wherein the alarm device includes an electrical impedance at a minimum operating frequency equal to an anti-resonance frequency that is between about 1.75 and about 2.25 times the DC impedance.   The apparatus of claim 1, wherein the anti-resonance frequency is less than 1000 Hz. Trigger device configured to trigger an alarm signal according to the condition,
An alarm device having a tube and a speaker coupled to a first end of the tube, the sound generated by the speaker being directed through the tube to provide an audible sound, the tube and The speaker is configured and sized to provide substantially the audible sound at an anti-resonant frequency that is between the peaks of the first and second resonant frequencies relative to the system impedance of the response spectrum for the tube and the speaker. An alarm device, and a detector device having a controller coupled to the trigger device and configured to activate the alarm device according to the alarm signal.   The apparatus according to claim 11, wherein the speaker is attached to a chamber in acoustic communication with the tube.   12. The apparatus of claim 11, wherein the speaker is attached to a chamber and divides the chamber into two volumes such that one volume is in acoustic communication with the tube.   The apparatus of claim 11, wherein the detector device includes one of a smoke detector, a fire alarm, and a carbon monoxide detector.   The apparatus of claim 11, wherein the audible sound includes a plurality of sounds.   The apparatus of claim 11, wherein the plurality of sounds share at least one peak frequency.   The apparatus of claim 11, wherein the audible sound comprises a voice message.   12. The apparatus of claim 11, wherein the alarm device includes an electrical impedance at a minimum operating frequency equal to an anti-resonance frequency that is between about 1 and about 3.5 times the DC impedance.   The apparatus of claim 11, wherein the alarm device includes an electrical impedance at a minimum operating frequency equal to an anti-resonance frequency that is between about 1.75 and about 2.25 times the DC impedance.   The apparatus of claim 11, wherein the anti-resonance frequency is less than 1000 Hz.   The apparatus of claim 11, further comprising a mechanism for adjusting the anti-resonance frequency.   The apparatus of claim 11, wherein the trigger device includes one of a sensor, a clock, and a manual operation. Providing an alarm device including an elongated cavity and a speaker coupled to a first end of the cavity, such that sound generated by the speaker passes through the cavity to provide an audible sound. The steps being directed,
Configuring the cavity and speaker to provide the audible sound substantially at an anti-resonant frequency that is between the peaks of the first and second resonant frequencies relative to the system impedance of the response spectrum for the speaker and the cavity. And a method of sounding an alarm comprising the step of generating the audible sound by operating the speaker.   24. The method of claim 23, wherein the audible sound includes at least one of a plurality of sounds and voice messages.   24. The method of claim 23, wherein the configuring step comprises providing an electrical impedance at a minimum operating frequency equal to an anti-resonant frequency that is between about 1 and 3.5 times the DC impedance.

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