JP5632227B2 - Alarm - Google Patents

Description

  The present invention relates to an alarm device, and for example, relates to an alarm device that sounds a gas leak or fire by sounding a buzzer.

  In the alarm device for alarming gas leak or fire as described above, when a gas leak or fire occurs, the sound pressure of the alarm sound output from the buzzer or speaker is set to a large sound pressure of 70 dB / m or more. It is stipulated in. On the other hand, the above alarm device also detects a failure of the alarm device itself (for example, a circuit failure, a sensor failure, a memory failure, etc.), a battery voltage drop, an expiration date for replacement, etc. Some have a function of sounding a buzzer.

  The alarm sound pressure of the buzzer when such a failure of the alarm device itself is detected does not have to be a large sound pressure as in the case of a gas leak or a fire alarm, and the sound pressure is small enough to make the user aware. If there is enough. This is because it is not preferable that the loud sound continues to sound although it is not an alarm such as a gas leak or a fire, which gives anxiety and discomfort to the user.

  Therefore, conventionally, for example, as shown in FIG. 4, by adding an applied voltage switching circuit 12 for switching a voltage applied to a buzzer in addition to a buzzer oscillation circuit 11 for sounding a buzzer, when a gas leak or a fire is detected. The sound pressure of the alarm was switched when a failure was detected. For example, if the voltage applied to the buzzer is halved, the 6 dB sound pressure can be reduced.

  As shown in FIG. 4, the buzzer oscillation circuit 11 includes a 2-input NAND gate 11A and a 1-input NAND gate 11B to which the output of the NAND gate 11A is input. The output of the NAND gate 11A is fed back to one of two inputs via resistors R1 and R2. The NAND gate 11B is fed back to the input via the capacitor C1 and the resistor R1, and the output of the NAND gate 11B becomes the output of the buzzer oscillation circuit 11.

  When the buzzer oscillation circuit 11 configured as described above supplies a Hi level signal to the other of the two inputs of the NAND gate 11A, it oscillates and outputs a pulse-like drive signal that repeats Hi and Lo from the output of the NAND gate 11B. .

  The pulsed drive signal output from the buzzer oscillation circuit 11 is supplied to the base of the transistor Tr1 connected in series with the buzzer Bz between the power supply voltage V and the ground. The transistor Tr1 is turned on / off according to the driving signals Hi and Lo, and intermittently applies a voltage to the buzzer Bz. Thereby, the buzzer Bz vibrates and rings.

  The applied voltage switching circuit 12 includes resistors R3 and R4 that are connected in parallel to the buzzer Bz and that divide the power supply voltage V, a transistor Tr2 that is connected in series to the resistors R3 and R4, a power supply voltage V, and a buzzer Bz. And a transistor Tr3 and an operational amplifier 12A. The operational amplifier 12A has one input connected to the connection point of the resistors R3 and R4, the other input connected to the collector of the transistor Tr1, and the output connected to the base of the transistor Tr3.

  According to the above configuration, when a Lo level signal is input to the base of the transistor Tr2, the transistor Tr2 is turned off, and the power supply voltage V is supplied to one input of the operational amplifier 12A. Since the operational amplifier 12A controls the transistor Tr3 so that the other input has the same power supply voltage V as the other, the power supply voltage V is applied to the buzzer Bz.

  On the other hand, when a Hi level signal is input to the base of the transistor Tr2, the transistor Tr2 is turned on, and a divided voltage (<power supply voltage V) obtained by dividing the power supply voltage V is supplied to one input of the operational amplifier 12A. Similarly, since the operational amplifier 12A controls the transistor Tr3 so that the other input has the same divided voltage as the other, the divided voltage is applied to the buzzer Bz. Therefore, the voltage applied to the buzzer Bz is the power supply voltage. It is possible to switch to a divided voltage smaller than V.

  However, in order to switch the applied voltage to the buzzer Bz, it is necessary to add the applied voltage switching circuit 12 described above, which increases the cost. Therefore, as a method for switching the sound pressure of the buzzer Bz, for example, it is conceivable to apply a method for switching the frequency of the drive signal supplied to the buzzer Bz as shown in Patent Document 1.

  More specifically, some buzzers Bz have a sound pressure frequency characteristic in which the sound pressure increases as the frequency of the drive signal increases, for example. More specifically, if a 4 kHz drive signal is output to the buzzer Bz, the sound pressure is 80 dB / m, and if a 400 Hz drive signal is output, the sound pressure is 60 dB / m, and the voltage applied to the buzzer Bz is not changed. Sound pressure can be switched.

  Therefore, when a gas leak or fire is detected, for example, a 4 kHz drive signal is output, and when a circuit failure or the like is detected, a 400 Hz drive signal is output. The sound pressure can be switched with.

  However, in the conventional sound pressure switching by the conventional frequency switching described above, it is necessary to change the frequency greatly, and the sound is different in the case of a gas leak fire and in the case of detection of a circuit failure or the like, and the user feels uncomfortable. There was a problem of giving.

JP 7-319477 A

  Therefore, an object of the present invention is to provide an alarm device that can switch the sound pressure without changing the timbre at low cost.

  The invention according to claim 1 for solving the above-described problem is to provide a buzzer having a sound pressure frequency characteristic in which peaks and troughs of sound pressure appear alternately according to the frequency, and supply a drive signal to the buzzer. And a central processing unit for sounding the buzzer, wherein the central processing unit switches the frequency of the drive signal between the first frequency and the second frequency according to the content of the alarm. When the first frequency is set to a frequency that is a peak of the sound pressure, and the second frequency is shifted from the first frequency in an increasing direction or a decreasing direction, a sound corresponding to the first frequency is first set. The alarm device is characterized in that the frequency is set to a sound pressure valley where the difference from the pressure becomes a predetermined value or more.

  The invention according to claim 2 detects at least one of the first detection means for detecting at least one of gas leak and fire, and failure of the alarm device itself, decrease in battery voltage, and arrival of alarm device replacement deadline. A second detection means, wherein the central processing unit supplies a drive signal of the first frequency to the buzzer when detected by the first detection means, and is detected by the second detection means. 2. The alarm device according to claim 1, wherein a driving signal having the second frequency is supplied to the buzzer when the alarm is transmitted.

  As described above, according to the first aspect of the present invention, the central processing unit switches the frequency of the drive signal between the first frequency and the second frequency in accordance with the content of the alarm. The first frequency is set to a frequency that is a peak of sound pressure, and when the second frequency is shifted from the first frequency in the increasing direction or decreasing direction, a difference from the sound pressure corresponding to the first frequency is first determined. It is set to a frequency that is a valley of sound pressure that exceeds the value. Therefore, the sound pressure of the buzzer can be switched without changing the applied voltage switching circuit simply by changing the frequency of the drive signal output from the central processing unit. In addition, since the second frequency is a valley of sound pressures where the difference from the sound pressure corresponding to the first frequency first becomes a predetermined value or more when shifted from the first frequency, the first frequency and the second frequency Since the difference between the sound pressure corresponding to the first frequency and the sound pressure corresponding to the second frequency can be increased while minimizing the frequency difference to the maximum, an alarm device that can switch the sound pressure without changing the tone is inexpensive. Can be provided.

  According to the second aspect of the present invention, when at least one of gas leakage and fire is detected by the first detection means, the drive signal of the first frequency is supplied to the buzzer, and the buzzer sounds with a large sound pressure. On the other hand, when the second detection means detects at least one of a failure of the alarm device itself, a decrease in battery voltage and the arrival of the alarm replacement deadline, a drive signal of the second frequency is supplied to the buzzer, and the buzzer generates a small sound pressure. It rings. As a result, the sound pressure can be changed without changing the timbre when the gas leak and fire are detected, and when the alarm device itself fails, when the battery voltage drops and when the alarm device replacement deadline arrives. It does not give a sense of pleasure or incongruity.

It is a circuit diagram which shows one Embodiment of the alarm device of this invention. It is a graph which shows the sound pressure frequency characteristic of the buzzer which comprises the alarm device shown in FIG. It is a flowchart which shows the process sequence of CPU which comprises the alarm device shown in FIG. It is a circuit diagram which shows an example of the applied voltage switching circuit used in order to switch the sound pressure of the conventional buzzer.

  Hereinafter, the alarm device of the present invention will be described with reference to FIGS. As shown in FIG. 1, the alarm device 1 includes a gas sensor 2 for detecting a gas leak, a fire sensor 3 for detecting a fire, and a failure detection circuit 4 for detecting a failure of the alarm device 1 itself. The battery voltage drop detection circuit 5 for detecting the voltage drop of the battery that supplies power to the alarm device 1, the timer 6 that counts the elapsed time since the alarm device 1 is installed, and the control of the entire alarm device 1 CPU 7 serving as a central processing unit for controlling the sound and a buzzer Bz for generating an alarm sound.

  A well-known gas sensor 2 and fire sensor 3 as first detection means are connected to the CPU 7 described above, and the CPU 7 detects gas leakage and fire based on outputs from the gas sensor 2 and fire sensor 3. Further, the failure detection circuit 4, the battery voltage drop detection circuit 5, and the timer 6 as the second detection means are connected to the CPU 7 described above, and the CPU 7 includes the failure detection circuit 4 and the battery voltage drop detection circuit 5. Or a decrease in battery voltage is detected based on the output of the timer 6 or the count value of the timer 6, or the arrival of replacement time is detected.

  Further, the CPU 7 described above is connected to the buzzer Bz and supplies a pulsed drive signal to the buzzer Bz. When a drive signal is supplied from the CPU 7, the buzzer Bz vibrates at the frequency of the drive signal and rings.

  Next, the sound pressure frequency characteristics of the buzzer Bz described above will be described with reference to FIG. This sound pressure frequency characteristic shows the result of supplying a 3V drive signal to the buzzer Bz and measuring the sound pressure at a position 10 cm away from the buzzer Bz. As shown in the figure, the sound pressure of the buzzer Bz increases from 100 Hz to 5 kHz. At this time, the sound pressure of the buzzer Bz does not increase gently from 100 Hz to 5 kHz, but increases while moving up and down so that the peaks and valleys of the sound pressure appear alternately as the frequency increases. The increase / decrease width between the peaks and valleys of the sound pressure increases as the frequency increases.

  In the present embodiment, the CPU 7 switches the frequency of the drive signal supplied to the buzzer Bz between the first frequency and the second frequency according to the content of the alarm. That is, the CPU 7 supplies a drive signal of the first frequency to the buzzer Bz when a gas leak or a fire is detected, and sends a drive signal of the second frequency to the buzzer Bz when a failure, a battery voltage drop, or a replacement deadline is detected. Supply.

  In the present embodiment, the first frequency is set to 4 kHz, which is a frequency that becomes the above-described peak of sound pressure. Here, the frequency that becomes the peak of the sound pressure is a frequency corresponding to the highest sound pressure among the portions that decrease after the sound pressure increases with respect to the frequency increase in the sound pressure frequency characteristics shown in FIG. By supplying this 4 kHz drive signal to the buzzer Bz, a sound pressure of about 80 dB can be obtained.

  As the second frequency, when the first frequency (4 kHz) is shifted in the decreasing direction, the difference from the sound pressure (about 80 dB) corresponding to the first frequency (4 kHz) first is, for example, 20 dB (predetermined value) or more. It is set to 3 kHz which is a frequency that becomes a valley of the sound pressure. Here, the frequency that becomes the valley of the sound pressure is a frequency corresponding to the lowest sound pressure among the portions that increase after the sound pressure decreases with increasing frequency in the sound pressure frequency characteristics shown in FIG. By supplying this 3 kHz drive signal to the buzzer Bz, a sound pressure of about 60 dB can be obtained.

  Next, details of the operation of the alarm device 1 described in the above outline will be described with reference to the flowchart shown in FIG. First, when the battery is inserted, the CPU 7 starts processing and takes in outputs from the gas sensor 2 and the fire sensor 3 to determine whether a gas leak or a fire has occurred (step S1). When the occurrence of gas leakage or fire is detected (Y in step S1), the CPU 7 supplies the drive signal of the first frequency (4 kHz) to the buzzer Bz (step S2), and then ends the process. As a result, the buzzer Bz rings with a large sound pressure of about 80 dB.

  On the other hand, if the occurrence of gas leakage or fire is not detected (N in step S1), the CPU 7 takes in the outputs of the failure detection circuit 4 and the battery voltage drop detection circuit 5 and the count value of the timer 6 to detect failure or It is determined whether the battery voltage has dropped or whether the replacement time has come (step S3). When a failure, a decrease in battery voltage, or the arrival of replacement time is detected (Y in step S3), the CPU 7 supplies the drive signal of the second frequency (3 kHz) to the buzzer Bz (step S4) and ends the process. As a result, the buzzer Bz rings at a sound pressure of about 60 dB, which is smaller than the sound pressure at the time of gas leakage or fire detection (about 80 dB).

  Further, if none of gas leakage, fire, failure, battery voltage drop, or replacement time is detected (N in step S1 and N in step S3), the CPU 7 immediately returns to step S1.

  According to the embodiment described above, the CPU 7 switches the frequency of the drive signal between the first frequency and the second frequency according to the content of the alarm. When the first frequency is set to 4 kHz, which is a frequency that becomes a peak of sound pressure, and the second frequency is shifted from the first frequency in the increasing direction or decreasing direction, the sound pressure corresponding to the first frequency first is The difference is set to 3 kHz, which is a frequency that becomes a valley of sound pressure at which the difference is 20 dB or more. Therefore, the sound pressure of the buzzer Bz can be switched by simply changing the frequency of the drive signal output by the CPU 7 without adding an applied voltage switching circuit. In addition, since the second frequency is a valley of sound pressures where the difference from the sound pressure corresponding to the first frequency first becomes 20 dB or more when shifted from the first frequency, the frequency of the first frequency and the second frequency Since the difference between the sound pressure corresponding to the first frequency and the sound pressure corresponding to the second frequency can be increased while minimizing the difference to the maximum, an alarm device that can switch the sound pressure without changing the tone is inexpensive. Can be provided.

  More specifically, for example, when 100 Hz is set as the second frequency, a small sound pressure of 60 dB can be obtained as in the case of setting to 3 kHz, but the difference between the first frequency and the second frequency is 3. Increases to 9 kHz. For this reason, the tone of the buzzer Bz when the drive signal of 100 Hz is supplied is heard to be considerably lower than the tone of the buzzer Bz when the drive signal of 4 kHz is supplied. On the other hand, in the present embodiment, since the second frequency is set to 3 kHz, which is the first sound pressure trough, when a 4 kHz drive signal is supplied, and when a 3 kHz drive signal is supplied, Then, there is almost no difference in the tone of the buzzer Bz, and the user can hear the same tone.

  Further, according to the above-described embodiment, when a gas leak and a fire are detected, a drive signal having the first frequency (4 kHz) is supplied to the buzzer Bz, and the buzzer Bz rings with a large sound pressure of 80 dB. On the other hand, when a failure of the alarm device 1 itself, a decrease in battery voltage, and the arrival of the replacement time for the alarm device 1 are detected, a drive signal of the second frequency (3 kHz) is supplied to the buzzer Bz, and the buzzer Bz has a low sound pressure. It rings. As a result, the sound pressure can be changed without changing the timbre when the gas leak and fire are detected, and when the alarm device itself fails, when the battery voltage drops and when the alarm device replacement deadline arrives. It does not give a sense of pleasure or incongruity.

  In the above-described embodiment, a sound pressure trough (hereinafter referred to as “decreasing direction”) in which the difference from the sound pressure of 80 dB corresponding to the first frequency is initially 20 dB or more when shifted from the first frequency (4 kHz) in the decreasing direction. (The abbreviation of “sound pressure valley”) and the difference between the sound pressure of 80 dB corresponding to the first frequency first becomes 20 dB or more when shifted from the first frequency (4 kHz) in the increasing direction. Of the frequency 9 kHz, which is a valley of pressure (hereinafter abbreviated as “sound pressure valley in the increasing direction”), the frequency 3 kHz, which is the valley of the sound pressure in the decreasing direction, is set as the second frequency.

  This is because the frequency characteristic (FIG. 2) of the buzzer Bz used in the present embodiment is higher than the difference between the first frequency (4 kHz) and the frequency 9 kHz that is the valley of the sound pressure in the increasing direction. ) And the frequency 3 kHz of the sound pressure valley in the decreasing direction is small. However, the present invention is not limited to this. For example, the buzzer Bz having a sound pressure frequency characteristic in which the difference between the first frequency and the frequency that becomes the valley of the sound pressure in the increasing direction is smaller than the difference between the first frequency and the frequency that becomes the valley of the sound pressure in the decreasing direction. When used, the second frequency may be set to a frequency that becomes the valley of the sound pressure in the increasing direction.

  In the above-described embodiment, both the gas leak and the fire are detected. However, the present invention is not limited to this, and any apparatus that detects at least one of the gas leak and the fire may be used. In the above-described embodiment, all of the failure of the alarm device 1 itself, the decrease in the battery voltage, and the arrival of the replacement time of the alarm device 1 are detected. However, the present invention is not limited to this. What is necessary is just to detect at least one of failure of 1 itself, a drop in battery voltage, and the arrival of the replacement time of the alarm device 1.

  In the above-described embodiment, the frequency of the drive signal is switched between the gas leak, the fire alarm, the failure of the alarm device 1 itself, the battery voltage drop, and the time for replacement of the alarm device 1. The present invention is not limited to this. These are merely examples, and the present invention only needs to switch the frequency depending on the alarm content.

  Further, the above-described embodiments are merely representative forms of the present invention, and the present invention is not limited to the embodiments. That is, various modifications can be made without departing from the scope of the present invention.

1 Alarm 2 Gas sensor (first detection means)
3 Fire sensor (first detection means)
4 Failure detection circuit (second detection means)
5 Battery voltage drop detection circuit (second detection means)
6 Timer (second detection means)
7 CPU (Central Processing Unit)
Bz buzzer

Claims (2)

A buzzer having a sound pressure frequency characteristic in which peaks and troughs of sound pressure appear alternately according to the frequency, and a central processing unit for supplying a drive signal to the buzzer to cause the buzzer to sound In the vessel
The central processing unit switches the frequency of the drive signal between the first frequency and the second frequency according to the content of the alarm,
The first frequency is set to a frequency that is a peak of the sound pressure;
When the second frequency is shifted from the first frequency in an increasing direction or a decreasing direction, the frequency is first set to a frequency that becomes a trough of a sound pressure at which a difference from the sound pressure corresponding to the first frequency becomes a predetermined value or more. An alarm device characterized by being provided. First detection means for detecting at least one of a gas leak and a fire;
A second detection means for detecting at least one of a failure of the alarm device itself, a drop in battery voltage, and an expiration date of the alarm device, and
The central processing unit supplies the first frequency drive signal to the buzzer when detected by the first detecting means, and the second frequency drive signal when detected by the second detecting means. The alarm device according to claim 1, wherein the alarm is supplied to the buzzer.

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