JPS608999A - Alarm - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alarm device that issues an alarm when the distance between a transmitter and a receiver increases beyond a certain level.

This type of alarm device can be effectively used, for example, as a device to prevent items from being left behind.

The transmitting device is set in baggage such as a hand pack or trunk, and the receiving device is carried by the person carrying the baggage.

If the baggage is near the carryer and the distance between the transmitter and the receiver is small, the alarm will not be issued, but if the baggage leaves the bearer and is left behind, the receiver will issue an acoustic alert. is generated. Therefore, such a device can be effectively applied to monitoring the whereabouts of an infant by having the infant carry an anti-theft device or a transmitting device.

Such alarm devices are configured so that a transmitter transmits a signal at a specified frequency using extremely weak radio waves, and a receiver receives the transmitted radio waves, and the distance between the transmitter and the receiver is For example, when the received signal level at the receiving device decreases when the receiving device is several meters or more away, the receiving device detects the sound of the received signal level decreasing,
A sound device such as a buzzer sounds to generate good news.

In this case, by making the transmission frequency of the receiving device equal to the reception tuning frequency of the receiving device, correlation is established between the transmitting device and the receiving device.

There is no problem when such alarm devices are used alone, but when multiple sets are used in close proximity, there is a risk of interference between the devices in each set, resulting in malfunction. . In order to avoid this, it is conceivable to use different types of radio waves (frequencies) for each alarm device. However, since there is a limit to the range of radio waves that can be used, only a limited number of sets can be set, and there is a difference in the transmittance of radio waves, making it difficult to operate with equal characteristics. be.

This invention was made in view of the above points, and while it uses radio waves of the same frequency so that the transmittance etc. can be set to a uniform state, it is sufficiently simple to set up a large number of channels, and can be used for multiple sets. It is an object of the present invention to provide an alarm device that can reliably perform an identification operation for each group even when the devices are used in close proximity to each other at the same time.

That is, the alarm device according to the present invention uses a tuning fork that mechanically vibrates at a specific frequency, and transmits a signal with a frequency of 1 to 10 on a specified carrier wave in response to the vibration of the tuning fork, and also In this case, a filter circuit using a tuning fork that vibrates at the same frequency as the tuning fork described above is installed, and from among the received and demodulated signals, only the signal from the specified transmitter can be identified and detected, and the detected signal is This is to generate good news by means of acoustics or the like at a low level or in a non-existent state.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a transmitting device that is stored and set in baggage, etc. when used as a device to prevent items left behind.
4. That is, in this oscillator 14, the tuning fork 1
This frequency signal is supplied as a control signal to a carrier wave oscillator 17 consisting of a crystal 15 and a transistor 16, and the carrier wave is amplitude-modulated by the frequency signal. Then, a carrier wave signal containing a signal component corresponding to the vibration frequency of the tuning fork 13 is transmitted from the antenna 18 as a radio wave.

In addition, 19 is the power supply of this receiving device, which is set to the operating state by switch 2θ, and this operating state is set to the LE
This can be confirmed on the display 21 such as D.

FIG. 2 shows a receiving device that receives radio waves from the transmitting device shown in FIG.
The signal is received by a suit mother hetero gain circuit 27 consisting of the following.

The signal received by this circuit 27 is detected by a diode 28 and then passed through a filter circuit 2 consisting of a capacitor and a resistor.
9 extracts the frequency signal component of the transmitting device, and this demodulated signal component is transmitted to the transistor 3.
The signal is amplified by an amplifier based on 0 and supplied to a filter circuit 32 equipped with a tuning fork 31. In this case, the tuning fork 31 is configured to vibrate at the same frequency as the tuning fork 13 used in the paired oscillation device.

That is, when a radio wave transmitted from a paired receiving device is received by this receiving device, an output signal is taken out from this tuning fork filter circuit 32, and the output signal from this filter circuit 32 is amplified by a transistor 33. to control the pace of transistor 34.

This transistor 34 controls the power supply of a sound generator 38 consisting of transistors 35 and 36 and a bus 37. When an input signal is present in the transistor 34, conduction occurs between its collector and emitter to generate sound. prevent a predetermined power from being supplied to the device 38;
In a state where a sufficient output signal is obtained from the tuning fork filter circuit 32, an acoustic alarm is not generated. Then, when the output signal level from the filter circuit 32 is low and the pace potential of the transistor 34 becomes a low level, power is supplied to the sound generating circuit 38 so that the buzzer 37 generates an alarm sound. It becomes.

Reference numeral 39 denotes a power source for this receiving device, and when a switch 40 is turned on, the operating state of this receiving device is set, and this operating state is displayed on an indicator 41 such as an LED.

In other words, in an alarm device configured as described above, a pair relationship is set by the natural frequencies of the tuning forks 13 and 31, which are respectively set in the transmitter and receiver, and the transmitter in this pair relationship is The receiving device only monitors the presence of radio waves transmitted from the device.

The frequency of the tuning fork 13.31 used here is set within the range of 300 Hz to 3'OOOOHz, for example, if the frequency is varied every 15 Hz, 180 channels of signal waves can be set. That is, 180 channels are set using radio waves using carrier waves of the same frequency, and mutual interference can be sufficiently avoided even when multiple sets of alarm devices are used at the same location.

In this case, since a tuning fork is fully used as a signal source, the signal frequency of each alarm device can be easily set within the necessary and sufficient range, and it is possible to ensure stable operation over a long period of time, reducing consumption. Electric power can also be sufficiently reduced. In other words, the configuration can be sufficiently simplified while allowing a very large number of channels to be set.

As described above, according to the present invention, an alarm device that issues an alarm when the distance between a transmitting device and a receiving device is greater than a certain distance can be easily configured to have multiple channels so that they can be sufficiently distinguished from each other. It will enable you to
For example, it can be effectively used as a lost item prevention device for storing and setting the transmitting device in hand luggage, a theft prevention device for storing the transmitting device in valuables, etc., and a lost child monitoring device for allowing the transmitting device to be carried by an infant. In particular, since it is easy to create multiple channels, there is no mutual interference even when multiple sets are used in the same place, and the alarm operation is performed with certainty, which is a significant effect. .

[Brief explanation of drawings]

The accompanying drawings are for explaining an alarm device according to an embodiment of the present invention, and FIG. 1 is a circuit diagram showing a transmitting device, and FIG. 2 is a circuit diagram showing a receiving device. 13... Tuning fork, 14... Tuning fork oscillator, 17... Carrier wave oscillator, 18... Antenna (transmission), 22...
Antenna (reception) 1, 97...Superheterodyne circuit, 28...Diode, 29...Filter circuit (
demodulation), 31... tuning fork, 32... tuning fork filter circuit, 34... transistor (sound generation circuit power supply control),
38...Sound generation circuit. Applicant's agent Patent attorney Takehiko Suzue 9-

Claims (1)

[Claims] A transmitting device includes a tuning fork oscillator that generates a frequency signal corresponding to the vibration of the tuning fork, a modulation circuit that modulates a carrier signal with the frequency signal from the tuning fork oscillator to generate a transmission signal, and a transmitting device that generates a signal from the transmitting device. A receiving device equipped with a tuning fork filter circuit to which the received and demodulated signal is supplied and whose passing frequency is specified by the vibration of the tuning fork, and an alarm generating circuit which generates an alarm when the signal level passing through the filter circuit is insufficient. An alarm device characterized by: