JP2881494B2 - Double mode ultrasonic alarm - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of an ultrasonic alarm.

[Conventional technology]

Conventionally, as this type of alarm, utilizing the fact that a detection field is created by constantly emitting ultrasonic waves, and when an intruder enters the detection field, the frequency reflected on the intruder undergoes Doppler shift, A Doppler-type ultrasonic alarm that detects the presence of an intruder, or an ultrasonic pulse that is emitted from the ultrasonic transmission unit at a fixed cycle, and the reflection time is compared with the normal reflection time to determine the intruder There is known a pulse-echo type ultrasonic alarm which detects the presence of a pulse.

[Problems to be solved by the invention]

In the former among those described in the related art, the Doppler frequency is also detected by factors other than the intruder, for example, the disturbance of air caused by the start / stop of the cooling / heating device installed in the alert area, the air current, etc. There is a problem that an alarm (so-called false alarm) may be output.

Further, in the latter case, the distance reached by the pulse changes due to a temperature change in the alert range, and the sensing area fluctuates (whether the alert area becomes substantially wider or narrower). There is a problem in that the movement of an object outside the range is detected, and conversely, if the movement is narrowed, it cannot be detected even if there is an intruder.

Therefore, the present invention has been made in view of such problems of the prior art, and has as its object the sensing area is less affected by environmental changes in the alert area, and the reliability is low. It is to provide a high ultrasonic alarm.

[Means for solving the problem]

The present invention relates to a transmitting means for emitting an ultrasonic wave to a guard area, a receiving means, a detecting means for detecting a Doppler frequency component in an ultrasonic frequency received by the receiving means, and a received Doppler frequency. Tentatively determining the presence or absence of an intruder based on the level of the frequency component and the magnitude of the received level, and outputting an intruder signal when it is determined that there is an intruder; When a user signal is input, a mode change signal for changing an ultrasonic wave emitted from the transmitting means to a pulse output is output, and a reflection time from emission of a pulse signal to reception of a pulse echo is measured. A central processing means having a timer for performing the operation, and a mode changing means for changing an ultrasonic wave emitted from the wave transmitting means to a pulse output when a mode change signal output from the central processing means is input. If the reflection time from the output of the pulse signal to the reception of the pulse echo is within a predetermined time, an alarm signal is output as the presence of an intruder, and a double mode ultrasonic alarm is provided. Machine.

[Action]

The double mode ultrasonic alarm according to the present invention usually operates as a Doppler type ultrasonic alarm, and checks the presence or absence of a Doppler frequency by a wave receiving unit. When the Doppler frequency is received, the presence or absence of an intruder is provisionally determined based on the level of the received Doppler frequency and the level of the reception level of the frequency component. When it is determined that there is an intruder, the mode is changed to the pulse mode, the ultrasonic wave pulse is periodically emitted from the transmitting means to the space within the alert range, and the pulse echo is received by the receiving means. Then, the distance to the target object is measured based on the time from the emission of the ultrasonic pulse to the reception of the pulse echo, and if it is determined that the target object is within the alert range, the An alarm is output to an external alarm device when there is a user.

〔Example〕

 FIG. 1 is a block diagram showing the configuration of the present invention.

In the figure, an alarm device 10 according to the present invention includes a transmitting means (transmitting ultrasonic transducer) 11 for emitting ultrasonic waves to a space in a guard area, and the transmitting means when in a normal mode or a pulse mode. Receiving means (receiving ultrasonic transducer) 21 capable of receiving a Doppler wave or a pulse echo of an ultrasonic wave emitted from 11, a Doppler in an ultrasonic frequency received when the receiving means 21 is in a normal mode; Detecting means 25 for detecting a frequency component, determining means 16 for temporarily determining the presence or absence of an intruder based on the level of the frequency component of the received Doppler frequency and the level of the reception level, and this determining means
When the intruder signal output when 16 determines that there is an intruder is input, a mode change signal for changing (switching) the ultrasonic wave emitted from the transmitting means 11 from a normal output to a pulse output is output. A central processing means 17 having a timer for measuring a reflection time from outputting an ultrasonic pulse to receiving a pulse echo, and
And a mode changing means 13 for changing the ultrasonic wave emitted from the wave transmitting means 11 to a pulse output when a mode changing signal output from 17 is input. Thus, when it is confirmed that the time from the emission of the ultrasonic pulse to the reception of the pulse echo is within a predetermined time, it is determined that there is a true intruder, and the central processing unit 17 outputs the alarm unit 15 Outputs an alarm to

The wave transmitting means 11 is driven by a driving means 12. Further, the mode changing means 13 is constituted by a switch means for transmitting an ultrasonic wave having a frequency oscillated by the oscillating means 14 for electrically generating ultrasonic waves, and for changing the mode of the ultrasonic output from the normal mode to the pulse mode. The frequency of the ultrasonic wave is changed to O by the mode change signal output from the central processing unit 17.
N, OFF.

Reference numeral 22 denotes a bandpass filter that passes ultrasonic waves around the transmission frequency, reference numeral 23 denotes first amplifying means for electrically amplifying the ultrasonic waves received by the receiving means 21, and reference numeral 24 denotes an amplified received signal. This is a mixing means for mixing the transmitted transmission frequencies. The detection unit 25 generates a beat if the frequency component mixed by the mixing unit 24 includes a Doppler shift, but detects the Doppler wave by detecting the envelope. Reference numeral 26 denotes second amplification means for amplifying the detected Doppler wave component, and reference numeral 27 denotes a frequency / voltage conversion unit (hereinafter, referred to as F / V conversion means) for converting the frequency component of the Doppler wave into a voltage. Thus, the determination means 16 determines whether or not an intruder is based on the information on the Doppler frequency from the F / V conversion means 27 and the information on the reception level (voltage level) of the Doppler frequency from the second amplification means 26. Is determined. Reference numeral 30 denotes a reception level transmitting unit that transmits a level signal to the central processing unit 17 when a pulse echo of a predetermined level or more is detected.

(Operation of Embodiment) Next, the operation of the embodiment will be described.

This alarm is installed on the ceiling or wall of a building with a warning area in front of the corridor or door through which people pass. Output an alarm.

Further, the alarm device constantly emits ultrasonic waves from the transmitting means 11 to a space which is an alarm range so as to convert electric vibrations into compression waves in the ultrasonic region. If there is no object moving in the space within the alert range, the ultrasonic wave emitted from the oscillating means 14 is reflected by an object standing still in the space and received by the wave receiving means 21. At this time, when an intruder passes through the same space or a wind blows through the space, the frequency thereof is positively or negatively shifted and the wave receiving means 21 receives the frequency. The received ultrasonic waves pass through a band around the transmission frequency.
, And only the transmission frequency and the frequencies near the transmission frequency are the first
And the mixing means 24 mixes the frequency from the transmitting means 14 with the receiving frequency. If the received frequency contains a Doppler frequency component, a beat is generated,
The detection means 25 detects the beat and detects the Doppler shift. This shift is further amplified by the second amplification means 26, and the F / V conversion means 27 converts the Doppler frequency component into a voltage. Further, the second amplifying means 26 outputs a signal of the reception level of the Doppler frequency component to the determination means 16, so that the determination means 16 generates a Doppler frequency from a combination of the magnitude of the frequency component of the Doppler frequency and the magnitude of the reception level. It can be provisionally (primarily) determined whether or not the cause is an intruder. If the change exceeds a predetermined level, the central processing means 17 outputs a mode change signal to the mode change means 13. The provisional determination method in the normal mode in the central processing means 17 will be described with reference to an example shown in FIG. The F / V conversion means 27 converts the Doppler frequency component into a voltage, which can be represented as shown in FIG. That is, when the Doppler frequency component is high, the moving speed of the moving object is high, and when the voltage level is high, the moving object is a physically large object within the caution range and is fired. It is assumed that a significant portion of the wave is being reflected. Thus, the F / V conversion means 27
Can obtain information on the moving speed and size. More specifically, a determination map as shown in FIG. 2 is created for this determination, and when a specific area or a combination thereof is applied, it is provisionally determined that there is an intruder [for example, Eight regions are provided for convenience by dividing the voltage into four stages and the voltage level into two stages. If the Doppler frequency is low, it is determined to be caused by wind from an air conditioner or the like, and if it is high, it is determined to be caused by insects, etc., and the peak value of the received Doppler frequency is medium, high, and Only when the reception level falls within a large range is determined to be an intruder (hatched portion in FIG. 2)].

Thus, when the determining means 16 determines that there is an intruder, it outputs an intruder signal, and when the intruder signal is input to the central processing means 17, the central processing means 17 outputs a mode change signal and the mode changing means 13 Changes the mode from the normal mode adopting the Doppler type detection method to the pulse mode adopting the pulse echo type detection method (at a predetermined interval, the frequency from the oscillation means 14 is pulsed to the drive means 12 Output). Then, simultaneously with the emission of the ultrasonic pulse from the wave transmitting means 11, the timing gate of the central processing means 17 starts, and the timer starts. The receiving means 21 receives a pulse (pulse echo) reflected from the moving object that has generated the Doppler frequency, amplifies it with the first amplifying means 23, receives the pulse echo with the receiving level transmitting means 30, and receives the pulse echo. The level transmitting means 30 outputs a level signal to the central processing means 17. Then the timer is stopped in the central processing unit 17, a range in which the time is predetermined by measuring the time, that is, when receiving a pulse echo between reflection time t ₁ of t ₂ is in the object vigilance range And outputs a warning signal to the warning means 15 (see FIGS. 3A and 3B).

〔The invention's effect〕

Since the present invention is configured as described above,
The following effects are obtained.

Normally, the range of alert is monitored by the Doppler system, and when a Doppler wave is detected, it is provisionally determined from the frequency component and the reception level whether or not an intruder is present. The mode is changed to the pulse-echo method, and an intrusion alarm is output only when a pulse-echo is detected within a predetermined warning range.Moreover, a plurality of determination categories are provided to determine the criterion according to the environmental conditions of the warning range. Therefore, it is possible to obtain a highly reliable ultrasonic alarm device, in which it is possible to accurately catch only intruders and detect unintended objects other than intruders.

In addition, the wind and other noise sources that instantaneously pass through the warning range, even if Doppler monitoring determines that an intruder, the pulse echo method does not detect echo,
An ultrasonic alarm that is not affected by the environment can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIG. 2 is a diagram showing a case where the determining means constituting the present invention tentatively determines the presence or absence of an intruder from the relationship between the Doppler frequency and the voltage level. FIG. 3A is a diagram showing the relationship between the time and the echo level when the intruder is not in the alert area, and FIG. 3B is a diagram showing the relationship between the time and the echo level when the intruder is in the alert area. It is. 10 alarm device 11 transmitting means 13 mode changing means 16 determining means 17 central processing means 21 receiving means 25 detecting means

Claims (1)

(57) [Claims] 1. A transmitting means for emitting an ultrasonic wave to a guard area, a receiving means, a detecting means for detecting a Doppler frequency component in an ultrasonic frequency received by the receiving means, and a received Doppler Provisionally determine the presence or absence of an intruder based on the magnitude of the frequency component of the frequency and the magnitude of the reception level,
Determining means for outputting an intruder signal when it is determined that there is an intruder; and a mode change signal for changing the ultrasonic wave emitted from the transmitting means to pulse output when the intruder signal output by the determining means is input. And a central processing unit having a timer for measuring a reflection time from emitting a pulse signal to receiving a pulse echo, and when a mode change signal output from the central processing unit is input, Mode changing means for changing the ultrasonic wave emitted from the wave transmitting means to pulse output, wherein if the reflection time from outputting the pulse signal to receiving the pulse echo is within a predetermined time, the intruder A double mode ultrasonic alarm device, which outputs an alarm signal when there is an alarm.