JPH10248162A - Power-saving microwave detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sustain operation for a longer time regardless of degrading in detecting capability, instead of allowing power supply to run down and a microwave detector to become completely inoperative, by switching between power- saving mode and ordinary mode during use depending on situations. SOLUTION: There are two types of the control operation of a controller 15: Ordinary mode (more power is consumed but microwaves are favorably detected) and power-saving mode (the capability to detect microwaves is sacrificed but less power is consumed), and the mode is switched through the output of a voltage monitoring circuit 16. The voltage monitoring circuit 16 monitors the output of a power supply battery 12 at all times. When the voltage of the battery 12 is above a predetermined reference value, the output of the voltage monitoring circuit 16 is high. At this time the controller 15 operates in the ordinary mode. If the voltage of the battery 12 falls below the reference value, the output of the voltage monitoring circuit 16 changes to low. At this time, the controller 15 operates in the power-saving mode. Thereby influences of degradation in performance due to power saving can be minimized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave detector for detecting and notifying a microwave emitted from a measuring instrument or the like, and in particular, is designed to extend the operation continuation time with a built-in power supply using a battery. And a power-saving microwave detector.

[0002]

2. Description of the Related Art There has been known a microwave detector configured to detect a microwave emitted from a radar type speed measuring device and generate an alarm. This type of microwave detector is mainly configured with a superheterodyne receiving circuit, and when a microwave in a predetermined band is discriminated, an alarm is generated by a buzzer, an LED lamp, or the like.

[0003] In the case of a normal type microwave detector which always receives supply of operating power from the outside, a superheterodyne receiving circuit and other signal processing circuits are constantly operating. However, in the case of a small microwave detector that operates from a small-capacity built-in power supply such as a built-in battery or a solar cell, the receiving circuit and other major components are used to minimize power consumption and guarantee stable operation for a long time. It is configured to intermittently supply power to the signal processing circuit and operate it intermittently.

[0004]

SUMMARY OF THE INVENTION The present applicant has disclosed in
Japanese Patent Application No. -291978 has proposed a technique for further reducing power consumption of an intermittent operation type power-saving microwave detector without lowering detection performance as much as possible.

[0005] The technical problem addressed by the present invention is slightly different from the above-mentioned prior art, in that the operation can be continued for a longer time even if the detection performance is reduced, rather than completely stopping operation due to the power supply. That is. This is also a technique for switching from a high-performance normal operation mode to a low-power consumption mode as needed, instead of operating in an ultra-low power consumption mode with low detection performance from the beginning. It is an object of the present invention to provide a power saving microwave detector incorporating this technology.

[0006]

SUMMARY OF THE INVENTION A power saving type microwave detector according to the present invention is operated by a built-in power supply using a battery and generates an alarm by distinguishing microwaves in a predetermined band from an antenna input. A mode switching means for switching an operation mode between a normal mode which achieves high power consumption but high performance detection characteristics and a power saving mode which sacrifices the detection characteristics to reduce power consumption; And a control means for issuing a switching command to the mode switching means.

[0007] By doing so, the power saving mode and the normal mode are switched and used depending on the situation.
It is possible to continue the operation for a longer time even if the detection performance is lowered, rather than completely stopping the operation due to the power supply.
In addition, instead of operating in the ultra-low power consumption mode with low detection performance from the beginning, the system switches from the high-performance normal operation mode to the low power consumption mode as needed, so that the effects of performance degradation due to power savings are reduced. It is difficult to minimize.

[0008] A specific change in the predetermined factor is the remaining capacity of the battery. In other words, when the remaining capacity is reduced, the battery may run out immediately if operated in the normal mode. Therefore, when the remaining capacity decreases, the time until the battery runs out is lengthened by setting the power saving mode so that the battery can be charged or the battery can be replaced during that time.

As an actual configuration for performing such an operation, in the basic configuration according to the first aspect, when the voltage of the battery drops below a predetermined voltage, the mode is switched from the normal mode to the power saving mode. It can be configured (claim 2).

[0010] Another specific change in the predetermined factor is, for example, brightness. That is, the vehicle tends to travel at a higher speed in a bright case such as in the daytime than in a dark case such as at night or when the weather deteriorates such as rainy weather or snow. Therefore, there is a demand for reliable detection in the normal mode. On the other hand, when the vehicle is dark, the vehicle tends to run at a low speed. Therefore, even if the vehicle operates in the low-sensitivity power saving mode, there is little actual harm that causes detection delay, and the merit that the operation can be continued for a long time is greater. In particular, solar cells have low electromotive force or do not generate power when they are dark, so the battery capacity is depleted in the event that power cannot be generated due to continuous rain or snow, and in the worst case, the battery capacity is reduced. May run out (the battery may run out). However, according to the present invention, the power saving mode is set when the illuminance is equal to or less than a certain value, so that the possibility of running out of the battery is reduced as much as possible.

As an actual configuration for performing such an operation, for example, a means for detecting brightness is provided so that the mode is switched from the normal mode to the power saving mode when the brightness is below a predetermined level. (Claim 3). More specifically, the means for detecting the brightness includes:
The illuminance detector for detecting the illuminance of external light (claim 4), the built-in power supply includes a solar cell that generates power by external light and charges the battery, and the means for detecting the brightness includes: Alternatively, the electromotive force of the solar cell may be detected, and when the electromotive force is equal to or less than the reference value, the illuminance of the external light may be determined to be equal to or less than a predetermined level (claim 5). In this case, it is desirable to switch to the power saving mode when the state where the illuminance of the external light is equal to or lower than a predetermined level continues for a predetermined time or longer (claim 6).

Still another factor is automatic or manual sensitivity switching. That is, in a device provided with a sensitivity switch that switches between the high sensitivity mode and the low sensitivity mode by switching the microwave discrimination threshold, when the high sensitivity mode is selected by the sensitivity switch, the normal mode is set, When the low sensitivity mode is selected, the power saving mode can be set (claim 7).

Still another factor is the traveling speed. When the vehicle is traveling at high speed, the vehicle can be operated in the normal mode, and when traveling at low speed, the vehicle can be operated in the power saving mode. And as an actual realizing means, it can be determined based on the output of the vibration sensor. In other words, a vibration sensor that detects the vibration of the microwave detector is provided, and the output of the vibration sensor is processed to discriminate the vibration intensity and the vibration cycle. It is possible to configure so as to be in the normal mode in a short-period vibration state stronger than a predetermined state (claim 8).

[0014]

FIG. 1 shows the configuration of a first embodiment of the present invention. The configuration and operation of the receiving circuit block A are of the well-known double superheterodyne type. The input of the horn antenna 1 and the output of the first local oscillator 3 are frequency-mixed by the first mixer 2. The first intermediate frequency signal thus obtained and the output of the second local oscillator 5 are frequency-mixed by the second mixer 4, and the output is input to the detection circuit 7 via the intermediate frequency filter 6.

The receiving circuit block A operates intermittently as described below, and the output frequency of the second local oscillator 5 is swept from a predetermined value to a predetermined value by the sweep driver 25 during one operation period. As a result, a predetermined reception band is searched in one reception period. The signal processing circuit 8 monitors the output of the detection circuit 7 and discriminates whether or not there is a microwave reception signal during the detection output.

When a microwave reception signal is detected, the alarm circuit 9 connected to the subsequent stage of the reception circuit block A is operated, an alarm sound is generated by the piezoelectric speaker 10, and the LED lamp 11 is turned on and off.
The alarm circuit 9, the piezoelectric speaker 10, and the LED lamp 11 are always supplied with power.

The microwave detector of the embodiment shown in FIG. 1 operates using a built-in battery 12 as a power supply. The output of the battery 12 is stabilized by the power supply circuit 13 and is constantly supplied to the controller 15 and the voltage monitoring circuit 16, but is intermittently supplied to the above-mentioned receiving circuit block A via the power supply switch 14. It is the controller 15 that turns the power switch 14 on and off.

The controller 15 includes a receiving circuit block A
The power supply switch 14 is turned on for a short period of time at predetermined time intervals to supply power to the receiving circuit block A, and controls the sweep driver 25 during the power supply period. Thus, the output frequency of the second local oscillator 5 is swept from a predetermined value to a predetermined value. Under the control of the controller 15, the receiving circuit block A operates intermittently at a predetermined cycle, and power is not supplied during a long non-operation period during a short operation period.
It saves power.

The control operation of the controller 15 is not constant, and there are two modes, a normal mode and a power saving mode, which are switched as follows by the output of the voltage monitoring circuit 16. [Normal mode]... The cycle of the intermittent operation is short, the operation time for one operation is long, and the sweep speed is low. Although power consumption is large, microwave detection performance is high (see FIG. 2A). [Power saving mode]: The cycle of the intermittent operation is long, the operation time for one operation is short, and the sweep speed is high. Microwave detection performance is sacrificed, but power consumption is extremely small (second
(See FIG. (B)).

The voltage monitoring circuit 16 constantly monitors the output voltage of the power supply battery 12. If the battery voltage exceeds a predetermined reference value, the output of the voltage monitoring circuit 16 is at a high level. Operate in normal mode. When the battery voltage falls below the reference value, the output of the voltage monitoring circuit 16 changes to a low level, and at this time, the controller 15 operates in the power saving mode. A specific circuit configuration of the voltage monitoring circuit 16 is based on a comparator 16a as shown in FIG. 3, for example, and uses a terminal voltage of a constant voltage diode D connected to a power supply line as a reference voltage. Twelve output voltages can be discriminated by comparing with a voltage obtained by dividing the output voltage with a resistor.

FIG. 4 shows a second embodiment of the present invention. In this embodiment, the brightness of external light is detected, and the mode is switched depending on whether the brightness is equal to or higher than a reference. The following description focuses on portions different from the embodiment of FIG. 1, and the same or corresponding portions are denoted by the same reference numerals and description thereof is omitted. The microwave detector according to the second embodiment includes a solar cell 17 that generates an electromotive force by receiving external light, and is configured to charge the secondary battery 12 with the output of the solar cell 17. . The charging path includes a diode D1 for preventing backflow and a resistor R for detecting electromotive force.
1 are inserted in series.

The output monitoring circuit 18 is a circuit for comparing the voltage across the resistor R1 (proportional to the output current of the solar cell 17) with a reference voltage, and when the output (electromotive force) of the solar cell 17 is higher than the reference. The controller 15 is operated in the normal mode, and when the output of the solar cell 17 is lower than the reference, the controller 15 is operated in the power saving mode. That is,
When the illuminance decreases, the output of the solar cell 17 also decreases. Therefore, the illuminance can be indirectly known by monitoring the output.

In this case, the output monitoring circuit 18 is provided with an appropriate integration characteristic so as to switch to the power saving mode when the state where the output of the solar cell 17 becomes lower than the reference continues for a predetermined time or more.

Incidentally, in order to detect the illuminance of the external light, the illuminance may be directly detected by using a photosensor 19a whose resistance changes according to the illuminance as shown in FIG. 5, for example. That is, a series circuit of the photosensor 19a and the resistor R2 is arranged between the power supply line and the ground. Then, the power supply voltage becomes the resistance value of the photosensor 19a and the resistance R
Since the voltage is divided based on the ratio of the resistance values of 2, the terminal voltage of the photosensor 19a changes due to the change in illuminance. Then, by comparing the terminal voltage with a reference voltage generated by voltage division by the fixed resistors R3 and R4 by the comparator 19b, it is possible to discriminate whether or not the illuminance is equal to or more than the reference value. Therefore, the normal mode and the power saving mode may be switched by the output of the comparator 19b. In addition,
The illuminance discrimination circuit 19 based on the illuminance is installed, for example, instead of the voltage monitoring circuit 16 shown in FIG. 1 and is configured to eliminate the input line from the battery 12.
Implemented as a power saving microwave detector.

FIG. 6 shows a third embodiment of the present invention. The signal processing circuit 8 in the receiving circuit block A of this embodiment is provided with a sensitivity changeover switch 20. The sensitivity change switch 20 is a switch for switching between a high sensitivity mode and a low sensitivity mode by switching a microwave discrimination threshold.

The changeover selection signals a and b of the sensitivity changeover switch 20 are also used as the mode selection signals of the controller 15, and when the high sensitivity mode is selected by the sensitivity changeover switch 20, the controller 15 operates in the normal mode. When the low sensitivity mode is selected, the controller 15 operates in the power saving mode. The switching of the sensitivity may be either automatic or manual. Furthermore, in this embodiment, since the sensitivity is reduced by setting the power saving mode,
The signal processing circuit 8 does not perform the sensitivity switching processing, and the switching between the normal mode (high sensitivity) and the power saving mode (low sensitivity), which is a main part of the present invention, may be used as it is as the sensitivity switching processing.

FIG. 7 shows a fourth embodiment of the present invention. The microwave detector according to this embodiment includes a vibration sensor 21 for detecting vibration of the detector itself, a preprocessing circuit 22 for amplifying and filtering the output of the vibration sensor 21, and a preprocessing circuit. From the output of 22 the vibration level is 2
A level discriminating circuit 23 for discriminating a value and a cycle discriminating circuit 24 for discriminating a cycle of vibration from an output of the preprocessing circuit 22 in a binary manner are provided. The controller 15 operates as follows based on the outputs of the level discrimination circuit 23 and the cycle discrimination circuit 24.

That is, the microwave detector is mounted on an automobile. Therefore, when the vehicle is stopped, the vibration sensor 21 hardly detects vibration. In this case, the output S2 of the level discrimination circuit 23 is at a low level, the output S1 of the periodic discrimination circuit 24 is also at a low level, and the controller 15 does not operate the receiving circuit block A at all. When the vehicle runs at a low speed, the vibration sensor 21 detects a clear vibration, and the output S2 of the level discrimination circuit 23 becomes high.
However, the oscillation cycle is relatively long, and the output S1 of the cycle discrimination circuit 24 is at a low level. At this time, the controller 15 operates in the power saving mode. When the automobile runs at high speed, the output S1 of the periodic discrimination circuit 24 also becomes high, and at this time, the controller 15 operates in the normal mode.

[0029]

According to the power saving type microwave detector of the present invention,
Mode switching means for switching an operation mode between a normal mode which realizes high power consumption but high performance detection characteristics and a power saving mode which reduces power consumption at the expense of the detection characteristics, and the mode which is triggered by a change in a predetermined factor. Since the switching means is provided with a control means for issuing a switching command, the operation can be continued for a longer period of time even if the detection performance is reduced, rather than stopping operation completely due to the power supply. that too,
Rather than operating in the ultra-low power consumption mode with low detection performance from the beginning, the system switches from the high-performance normal operation mode to the low power consumption mode as needed, minimizing the impact of performance degradation due to power saving. I can stop it.

[Brief description of the drawings]

FIG. 1 is a block diagram of a power-saving microwave detector according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation of a normal mode and a power saving mode.

FIG. 3 is a diagram showing an internal structure of a voltage monitoring circuit.

FIG. 4 is a block diagram of a power saving microwave detector according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram of a main part showing a modification of the second embodiment.

FIG. 6 is a block diagram of a power saving type microwave detector according to a third embodiment of the present invention.

FIG. 7 is a block diagram of a power saving microwave detector according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Horn antenna 2 1st mixer 3 1st local oscillator 4 2nd mixer 5 2nd local oscillator 6 Intermediate frequency filter 7 Detection circuit 8 Signal processing circuit 9 Alarm circuit 10 Piezoelectric speaker 11 LED lamp 12 Battery 13 Power supply circuit 14 Power switch 15 Controller 16 Voltage monitoring circuit 17 Solar cell 18 Output monitoring circuit 19 Illumination discrimination circuit 20 Sensitivity changeover switch 21 Vibration sensor 22 Preprocessing circuit 23 Level discrimination circuit 24 Period discrimination circuit

Claims (8)

[Claims] 1. A microwave detector which operates from a built-in power supply using a battery and discriminates a microwave in a predetermined band from an antenna input to generate an alarm, and realizes high power consumption but high performance detection characteristics. A mode switching unit for switching an operation mode between a normal mode to be performed and a power saving mode for reducing power consumption at the expense of detection characteristics, and a control unit for issuing a switching command to the mode switching unit in response to a change in a predetermined factor. A power-saving microwave detector. 2. The power-saving microwave detector according to claim 1, wherein the mode is switched from the normal mode to the power-saving mode when the voltage of the battery drops below a predetermined voltage. 3. The power-saving microwave detector according to claim 1, further comprising means for detecting brightness, wherein the mode is switched from the normal mode to the power-saving mode when the brightness is equal to or lower than a predetermined level. 4. The power-saving microwave detector according to claim 3, wherein said means for detecting brightness is an illuminance detector for detecting illuminance of external light. 5. The method according to claim 3, wherein the built-in power supply includes a solar cell that generates power by external light to charge the battery, and the means for detecting brightness includes an electromotive force of the solar cell. A power-saving microwave detector characterized in that when detected and the electromotive force is less than a reference value, the illuminance of external light is determined to be less than a predetermined level. 6. The power-saving microwave detector according to claim 3, wherein the mode is switched to the power-saving mode when the illuminance of the external light is lower than a predetermined level for a predetermined time or longer. 7. A high-sensitivity mode according to claim 1, further comprising a sensitivity switch for switching between a high-sensitivity mode and a low-sensitivity mode by switching a microwave discrimination threshold. A power-saving microwave detector, wherein the power-saving mode is sometimes set to the normal mode, and the power-saving mode is set when the low-sensitivity mode is selected. 8. The apparatus according to claim 1, further comprising a vibration sensor for detecting the vibration of the microwave detector, processing an output of the vibration sensor to discriminate a vibration intensity and a vibration period, and weaker than a predetermined and longer period. A power-saving microwave detector, wherein the power-saving mode is set to the power-saving mode in a vibration state, and the normal mode is set to a short-period vibration state stronger than a predetermined state.