JPH0562084A - Left-behind thing preventing device - Google Patents

Abstract

PURPOSE:To detect that a thing is left behind and to inform of the effect. CONSTITUTION:A transmitter is equipped with an oscillating circuit 1 to generate a carrier and an amplitude modulating circuit 2 to amplitude-modulate a carrier by the generated signal wave with an Xtal, a receiver (not illustrated) has a demodulating circuit to demodulate a signal wave and the Xtal of the same oscillation frequency as the Xtal, and is equipped with a filter circuit to filter the signal wave demodulated by the demodulating circuit and a means to inform that the output of the filter circuit is the prescribed level or below. Then, when the transmitter is put in an article and the receiver is put in a breast pocket, the receiver in the breast pocket generates an alarm sound, etc., when it is away from the article by a certain distance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lost-item preventive device in which a transmitter and a receiver are combined so that when the radio wave from the transmitter does not reach the receiver, the receiver issues an alarm.

[0002]

2. Description of the Related Art Heretofore, there has been no suitable device for notifying belongings such as bags and luggage when they are left behind on the floor or in a vehicle. Therefore, after noticing that you left it for a while, you return to the place where you left it in a panic, or if you left it in the car, contact transportation, check if there is it, go to get it, etc. It is difficult to deal with misplaced items, and if the misplaced items are valuables or money, the situation becomes irreversible.

[0003]

However, in order to prevent such a situation from occurring, it is necessary to rely on the attention of each person. For this reason, there was a problem that even if you were careful, if you were in a panic, carelessly, or were thinking, you would forget.

It is an object of the present invention to solve the above-mentioned problems and to provide an apparatus capable of preventing a thing left behind without depending on the attention of each person.

[0005]

In order to solve the above problems, the present invention combines a transmitter and a receiver and informs the receiver that the radio wave from the transmitter has stopped reaching the receiver. In the preventer, the transmitter includes an oscillation circuit that generates a carrier, a modulation circuit that amplitude-modulates the carrier by a signal wave generated using Xtal, and a unit that transmits the carrier amplitude-modulated by the signal wave. The receiver has means for receiving the carrier transmitted by the transmitter, a demodulation circuit for demodulating a signal wave from the received carrier, and Xtal having the same oscillation frequency as Xtal.
The filter circuit detects the signal wave demodulated by the demodulation circuit, and means for notifying that the output of the filter circuit is below a predetermined level.

[0006]

According to the present invention, since the forgotten item protector is configured as described above, in the transmitter, the carrier generated by the oscillating circuit is modulated by the signal wave by the amplitude modulating circuit and transmitted by the means for transmitting, and the receiver is Then, the receiving means receives the carrier transmitted by the transmitter, the demodulation circuit demodulates the signal wave from the received carrier, the demodulated signal wave is detected by the filter circuit, and the output of the filter circuit is below a predetermined level. The notification means notifies.

Therefore, if the transmitter is placed in the item and the receiver is placed in the chest pocket, the receiver in the chest pocket issues an alarm sound when the product is separated from the item by a certain distance. You can be aware of and prevent lost items. The same method of use enables early detection and prevention of trades. In addition, if a child has a transmitter and an adult has a receiver, an alarm sound will be emitted from the receiver that the adult has when the child leaves the vicinity of the adult, and the alarm sound will prevent the child from getting lost. You can

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a circuit diagram of a transmitter according to an embodiment of the present invention. In the figure, reference numeral 1 is a self-excited oscillation circuit, which self-excitedly oscillates a carrier having a frequency determined by L _O and T _C. 2 is an amplitude modulation circuit, which is R ₁ , R ₂ , Q ₁ ,
_{C 1, R 3, Q 2} , performs amplitude modulation of the carrier generated by the self-excited oscillation circuit 1 with a signal wave oscillated by deformation piercing B-C circuit by Xtal. 3 is a power circuit, 2 AAA batteries
The power supply voltage was changed by switching the book to serial or parallel connection with a switch, and the transmission output was made variable in two steps. L ₁ and C ₃ are decoupling circuits for preventing sneaking into the high frequency power supply circuit 3, and L ₂ is an omnidirectional antenna.

FIG. 2 is a circuit diagram of a receiver in the embodiment of the present invention. In FIG, 4 is a super-regenerative detector-oscillating _{circuit, Q 1, L 0, T} C, the R ₁ to R ₆ and C ₁ -C ₄ constitutes a super-regenerative detector, than the emitter for Q ₁ for Q ₁ By feeding back to the load side, which is determined by the voltage division ratio of C ₂ and C ₃ , the operating state of the super regenerative detection circuit is on the verge of oscillation. Also, L
_An oscillation circuit is constituted by ₁ , L ₂ , C ₂ , C ₃ , R ₅ , R ₆ , R ₁ and R ₂ , and quenching oscillation is performed to generate a sharp sawtooth wave. That is, C ₂ , C ₃ , R ₁ , R
₂ , R ₅ and R ₆ are circuit elements common to the super reproduction detection circuit and the quenching oscillation circuit. L ₀ also acts as a receiver antenna.

Here, the input tuning circuit L_O, T_CResonate with
C when receiving the modulation frequency _FiveQuench to the output of
Ringing waveform appears. In this state, input tuning circuit L_O，
T_CWhen receiving a modulation frequency that resonates with the input tuning circuit
L_O, T_CSlope detection is performed by the selectivity curve of
Force tuning circuit L_O, T_CThe lower Q is the operating point
Therefore, this change is C₂, C₃Through the quenching frequency
Increase the number. As a result, the slope characteristics of the input tuning circuit
To demodulate the signal wave. Especially, if the
Therefore, Q is equivalently extremely high, and high-sensitivity detection is possible.
is there.

Demodulation demodulated by the super reproduction detection / oscillation circuit 4
The signal is Q₂, C_Five, C₆, C₇, R ₈, R₉， Inver
After passing through the amplifier circuit composed of
Installed in the modulator circuit of the transmitter to extract only the waves
Xtal, Q with the same oscillation frequency as Xtal₃, R₁₁，
R_TenIs input to the filter circuit 5. This output is D
₁, D₂, D₁₂, C₉Smoothed by C-MOS I
It is input to the C inverter circuit (2/6). In addition,
R to increase the inversion level sensitivity of the inverter (2/6)
₁₃, R₁₄The bias is applied in advance by.

The output of the inverter (2/6) is its input
Controlled by level H and L, input demodulated signal
When it disappears, H is output. As a result, R₁₅，
R₁₆, C _Ten, Inverter (3/6), inverter (4 /
The first oscillator circuit according to 6) operates, and
R₁₇, R₁₈, C₁₁, Inverter (5/6), Inverter
The second oscillator circuit by (6/6) also operates, and with this output
R₁₉, Q_Four, CH, BZ circuits are driven and the buzzer sounds
Occur. The first oscillator circuit determines the intermittent frequency.
However, the second oscillation circuit determines the oscillation pitch. Also,
D₃, D_FourIs the logic level setting of the first and second oscillator circuits.
CH is a diode for
It is a king coil.

In the above embodiment, the buzzer sound is used to notify that the output of the filter circuit is below a predetermined level, but it may be notified using a chime, a bell, a synthetic sound or the like. Alternatively, vibration may be generated by the motor and the vibration may be notified. In this way, it is effective when it is not desired to be known to others or when it is used in a place where an alarm sound cannot be emitted.

Furthermore, the present invention is not limited to the above-mentioned embodiments, but various modifications can be made within the scope of the present invention, and they are not excluded from the scope of the present invention.

[0015]

As described above in detail, according to the present invention, the following effects can be obtained. (1) Since Xtal is used for signal wave generation of the transmitter, amplitude modulation can be performed with a very stable signal. In the receiver as well, since the filter circuit uses Xtal having the same oscillation frequency as the transmitter, only the signal wave having the same oscillation frequency as Xtal from the transmitter can be detected,
Since only the frequency of this very stable signal wave is detected, it is possible to stabilize the signal wave and prevent malfunctions due to radio waves from other devices using the same frequency, thus improving reliability. (2) By using the demodulation circuit of the receiver as a super regenerative detection circuit and a quenching oscillation circuit having common circuit elements,
The demodulation circuit can be simplified and the demodulation sensitivity can be increased. Moreover, since the transmitter and receiver circuits are simplified, the transmitter and receiver can be made smaller, thinner, and lighter. (3) If the power supply voltage is switched and the distance until the alarm sound is generated is variable, it is effective especially when it is desired to prevent the child from getting lost and not to be sounded even if the user is moving a little and moving a little.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a transmitter according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a receiver according to an embodiment of the present invention.

[Explanation of symbols]

 1 Oscillation circuit 2 Amplitude modulation circuit 3 Power supply circuit 4 Super regenerative detection / oscillation circuit 5 Filter circuit

Front page continuation (72) Inventor Kenji Yamazaki 1-4-17 Shibata, Kita-ku, Osaka, Osaka Umeda Estate Building Otowa Denki Kogyo Co., Ltd. (72) Inventor Kazushi Otsuki 1 Shibata, Kita-ku, Osaka, Osaka -4-17 Umeda Estate Building Otowa Denki Kogyo Co., Ltd.

Claims (4)

[Claims] 1. A forgotten item prevention device in which a transmitter and a receiver are combined and the receiver notifies that the radio wave from the transmitter has not reached the receiver, wherein (a) the transmitter generates a carrier. An oscillation circuit, a modulation circuit that amplitude-modulates the carrier by a signal wave generated using Xtal, and a means that transmits the carrier amplitude-modulated by the signal wave, (b) the receiver is A means for receiving the carrier transmitted by the transmitter, a demodulation circuit for demodulating the signal wave from the received carrier, and an Xtal having the same oscillation frequency as the Xtal, and detecting the signal wave demodulated by the demodulation circuit. A forgotten item prevention device, comprising: a filter circuit; and means for informing that the output of the filter circuit is below a predetermined level. 2. The lost article protector according to claim 1, wherein the demodulation circuit is a super-reproduction detection circuit having a common circuit element and a quenching oscillation circuit. 3. A transmitter of a lost article preventive device, which comprises a transmitter and a receiver combined, and which informs the receiver that radio waves from the transmitter have not reached the receiver,
An oscillator circuit for generating a carrier, (b) a modulator circuit for amplitude-modulating the carrier by a signal wave generated by using Xtal, and (c) means for transmitting a carrier amplitude-modulated by the signal wave. A transmitter characterized by. 4. A receiver of a forgotten item prevention device, which comprises a transmitter and a receiver combined and notifies the receiver that radio waves from the transmitter have stopped reaching (a),
Means for receiving the carrier transmitted by the transmitter,
(B) a demodulation circuit for demodulating the signal wave from the received carrier, (b) a filter circuit having Xtal for detecting the signal wave demodulated by the demodulation circuit, and (c) an output of the filter circuit is predetermined. A receiver comprising means for notifying that the level is below the level.