JPH0328933B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an ultrasonic automatic height measuring device.

[Prior art and its problems] Conventionally, a height measuring instrument shown in FIG. 6, for example, has been used as an instrument for measuring a person's height. This instrument has a pillar 12 erected on a footrest 13, and an arm 14 is slid up and down along the pillar 12. That is, the person to be measured 15 stands on the footrest 13 and the arm 14 is brought into contact with the head of the person 15 .
The height of the person to be measured 15 is measured by reading the scale on the column 12 indicated by 4.

However, such a height measuring device is heavy and inconvenient to transport, and is bulky, so it requires a large space to store when not in use. Furthermore, when making measurements, it is necessary to bring the arm 14 into contact with the head, resulting in poor workability.

In order to solve this problem, an ultrasonic height measuring device has been proposed as a non-contact height measuring device (see Utility Model Application No. 188068/1983). When measuring height with this ultrasonic height measuring device, it is necessary to maintain a constant distance between the ultrasonic transmitter and the floor and to accurately measure that value in advance. For this reason, it is necessary to fix the transmitter in a predetermined position very precisely. Furthermore, if the measured value of the distance from the transmitter to the floor is inaccurate, the height value of the person measured will also be inaccurate. Furthermore, many switching operations are required before the measured value is displayed, and height measurement cannot be performed completely automatically. Furthermore, since it has a built-in memory circuit and arithmetic circuit, it is relatively difficult to supply it at low cost.

The present invention has been made in view of the above points, and has the ability to completely automatically measure a person's height just by standing on the measurement platform, has an automatic correction function for various errors, and has an automatic correction function for various errors. An object of the present invention is to provide an ultrasonic automatic height measuring device that does not require an arithmetic circuit, is lightweight, compact, and has an ultrasonic transmitting part that can be easily attached and installed.

[Means for Solving the Problems] The present invention includes an emitter that intermittently generates ultrasonic waves, a receiver that receives reflected waves of the ultrasonic waves, and a receiver that detects a person to be measured based on the output of the receiver. a signal generation device that notifies the person to be measured to leave the measurement table after the ultrasonic wave reflected from the head of the person to be measured enters the receiver; A transmission synchronization signal that generates a delayed signal delayed by a predetermined time, rises in synchronization with the first ultrasonic wave oscillation after the delay signal rises, and falls in synchronization with the first ultrasonic wave oscillation after the delay signal falls. and a control circuit for generating a reception synchronization signal that rises in synchronization with the first reception wave after the rise of the transmission synchronization signal and falls in synchronization with the first reception wave after the fall of the transmission synchronization signal, and the transmission synchronization signal. a decoder that creates a subtraction pulse gate from the time difference between the rises of the signal and the received synchronization signal, and creates an addition pulse gate from the time difference between the falls of the transmission synchronization signal and the reception synchronization signal, and a subtraction based on the subtraction pulse gate. This is an automatic ultrasonic height measuring device characterized by comprising a pulse and an addition/subtraction counter that adds and subtracts the addition pulse based on the addition pulse gate.

[Function] According to the ultrasonic automatic height measuring device according to the present invention, the device can be made compact by eliminating the need for a memory circuit or an arithmetic circuit. Furthermore, the above configuration can reduce errors caused by height differences between people and unnecessary reflected waves, thereby increasing measurement accuracy. Similarly, with the above configuration, complete automation of measurement and operation of the device using batteries can be realized.

[Examples] Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention. 1 in the figure is an oscillator. The oscillator 1 is connected to a temperature correction element 19 and has a temperature correction function. The oscillator 1 is configured to output a predetermined signal to a timing generation circuit 2 connected to a switching circuit 5 via a transmission gate 3. The switching circuit 4 is electrically interposed between the timing generating circuit 2 and the ultrasonic transmitter 5. The switching circuit 4 includes a differential amplifier 8
via a control circuit 17 and a person presence/absence determination circuit 18
A predetermined signal is output to a receiver 6 connected to the receiver 6. A charge/discharge circuit 7 is interposed between the transmission gate 3 and the differential amplifier 8. The human presence/absence determination circuit 18 includes a control circuit 17, a decoder 9,
It is electrically connected to a display section 11 via an addition/subtraction counter 10 in sequence. In addition, 20 in the same figure is
This is a battery for supplying a predetermined power to each part such as the oscillator 1.

In the ultrasonic automatic height measuring device configured as described above, the received wave determination output necessary for height measurement is generated in the following manner. That is, oscillator 1
When a predetermined signal is oscillated by , the timing generating circuit 2 divides the frequency of the oscillated output pulse to generate a basic timing signal 21 as shown in FIG. 2A. The monostable multi is triggered by the rise of this basic timing signal 21, and the second
A transmission gate signal 22a shown in Figure B is generated. By applying this transmission gate signal 22a to the charge/discharge circuit 7, a received wave comparison level signal 23 is obtained. That is, as shown in FIG. 3, the transmission gate signal 22a is supplied to the charging/discharging circuit 7 portion in an inverted state as shown in FIG. 2C, and the charging transistor is activated.
Since it is turned ON, the capacitor is charged rapidly and the voltage rises in a short time. Then the transmission gate signal 22
When a is reversed, the stored charge is gradually discharged through the resistor and the voltage across the capacitor drops exponentially. Therefore, a charging/discharging waveform as shown in FIG. 2D is obtained. This signal is referred to as a received wave comparison level signal 23. In reality, since the transmitter is also used as a receiving microphone, the transmitted wave is also applied to the receiver, and the received wave shown in Figure 4A includes this directly reflected wave 40a and unnecessary reflections from walls etc. wave 40
c and a head-reflected wave 40b reflected by the subject's head.
A reflected wave 40 consisting of the following is input. The reflected wave 40 output from the receiver 6 is input to a differential amplifier section 41 for blanking transmission waves shown in FIG. 3 of the differential amplifier 8.
When the signal passes through the transmitted wave blanking differential amplifier 41, a waveform 42 with the directly reflected wave 40a eliminated is obtained as shown in FIG. 4B. This waveform 42 further passes through a rectifying and smoothing circuit 43 shown in FIG. 3, and becomes a chevron-shaped waveform 44 as shown in FIG. 4C. This chevron waveform 4
4 and the above-mentioned received wave comparison level signal 23 are applied to the determination differential amplification section 45 of FIG. 3, all signals smaller than the received wave comparison level signal 23 are erased as shown in FIG. A signal larger than the wave comparison level signal 23 is amplified until the amplification section is saturated, and the received wave determination output signal 46 becomes as shown in FIG. 4E. Based on the received wave determination output signal 46 and the basic timing signal 21, a person presence/absence signal 26 is generated by the presence/absence determination circuit 18. In other words, it is ON when the object to be measured is close, and it is ON when the object to be measured is far away.
OFF, that is, if a person is directly under the receiver 6, it will be ON, and if the person leaves from under the receiver 6, it will be ON.
A presence/absence signal 26 that turns OFF is generated.

In the ultrasonic automatic height measuring device configured as described above, height measurement is performed by the signal processing shown in FIG. That is, when a person to be measured enters or leaves directly below the receiver 6, as shown in FIG.
occurs. When the presence/absence signal 26 is OFF, no measurement operation is performed. Measurement is performed when a person gets under the receiver 6 and the presence/absence signal 26 turns ON. but,
If measurements are taken immediately up to the top of the head at this time, there is a high possibility that a measurement error will occur because the person's posture is not stable. Therefore, as a certain delay time, for example, about 3
A delay signal 27 is created which is delayed by T time from the presence/absence signal 26 as shown in FIG. A reset signal 28 is generated from the delay signal 27 and the presence/absence signal 26 as shown in FIG. 5C, and the value of the addition/subtraction counter 10 is temporarily returned to zero by this reset signal 28.

Next, the delay signal 27 is latched at the rising edge of the transmission gate signal 22a to determine the rising edge 29a of the transmission synchronization delay signal 29 as shown in FIG. 5D. Rising portion 2 of this transmission synchronization delay signal 29
A first ultrasonic wave for measurement is transmitted in synchronization with 9a. The first ultrasonic wave is reflected above the subject's head and enters the receiver 6 . Upon receiving the output from the receiver 6, the received wave determination output signal 46 is generated by the differential amplifier 8 and the charging/discharging circuit 7 as described above with reference to FIG. The transmission synchronization delay signal 29 is latched at the rising edge of the received wave judgment output signal 46, and as shown in FIG.
Determine. In other words, the time t ₁ from the rising edge 29a of the transmitting synchronized delay signal 29 to the rising edge of the receiving synchronized delayed signal 30 is the time when the ultrasonic wave emitted from the ultrasonic transmitter 5 is reflected on the head of the subject and is transmitted to the receiver. This is the time required to return to 6.

Next, in synchronization with the falling portion of the delayed signal 27, the falling portion 29b of the transmission synchronization delay signal 29 is determined. A second ultrasonic wave for measurement is transmitted in synchronization with the falling portion 29b of the transmission synchronization delay signal 29. The second ultrasonic wave is directly reflected on the measurement table from which the subject has left and enters the receiver 6. A differential amplifier 8 and a charging/discharging circuit 7 receive the output from this receiver 6.
Then, the received wave determination output signal 46 is generated as described above with reference to FIG. This received wave judgment output signal 4
The transmission synchronization delay signal 29 is latched at the rising edge of 6, and the falling portion 30b of the reception synchronization delay signal 30 is determined. In other words, the time t ₂ from the falling portion 29b of the transmission synchronization delay signal 29 to the falling portion 30b of the reception synchronization delay signal 30 is due to the direct reflection of the ultrasound emitted from the ultrasound transmitter 5 on the measurement table. This is the time required to return to the receiver 6. In other words,
Transmission synchronization delay signal 29 and reception synchronization delay signal 30
Based on the time difference t ₁ between the rising portions 29a and 30a of
Also, based on the time difference _t2 between the falling portions 29b and 30b of the transmission synchronization delay signal 29 and the reception synchronization delay signal 30, an addition pulse gate 32 shown in FIG. 5G is created by the decoder 9. These subtraction pulse gate 31 and addition pulse gate 32 and FIG.
The fifth
A subtraction pulse 34 shown in FIG. I and an addition pulse 35 shown in FIG. 5J are obtained. That is, when the gate of the t ₁ second subtraction pulse 34 is opened, the count value becomes -L1. L1 is the distance from this device to the top of the head.
After that, the person leaves the device and transmits the synchronized delay signal 2.
After 9 turns OFF, the reception synchronization delay signal 30 starts.
Until it turns OFF, that is, t ₂ seconds addition pulse 3
If you open the gate 5, the count value L will be L=O-L1+
It becomes L2. Since L2 is the distance from this device to the measuring table, L matches the height. By displaying this value on the display unit 11, automatic height measurement can be performed. The operation of the addition/subtraction counter at this time is as shown in Fig. 5K: it is set when a person enters, then a subtraction operation for t ₁ seconds is performed, and when the person leaves, it is added for t ₂ seconds. The following actions are performed. Further, from the presence/absence signal 26 and the reception synchronization delay signal 30, a buzzer signal 36 shown in FIG. 5L is generated to notify the completion of the first measurement. The buzzer signal 36 turns ON immediately after receiving the reflected wave from the top of the head, and turns OFF when the person leaves. Therefore, the person stands under this device, corrects his/her posture, waits for the measurement of L1, and when the buzzer as a signal generator sounds, leaves from under the device, and when the measurement of L2 is completed, the calculated value L.
All you have to do is wait for it to be displayed. The displayed value will be retained until the counter is reset by the next person standing under the device.

In this way, the presence of the person to be measured can be automatically detected using the presence/absence signal 26, etc., and furthermore, the automatic measurement and display of the height as well as the removal of the person to be measured can be completely automatically controlled. Therefore, attachment and installation of the ultrasonic wave transmitting part can be made extremely easy. In addition, the height measurement process is performed using a chevron-shaped waveform 4 obtained by processing the reflected ultrasound wave 40 as shown in FIG.
4 and the received wave comparison level signal 23, the received wave judgment output signal 46 is used.
It is possible to electrically eliminate errors caused by reflected waves from walls and the like and differences in height between people, thereby automatically correcting measurement errors. Furthermore, since no memory or arithmetic circuit is used during measurement processing, the device can be made lightweight and compact. Incidentally, in the example, the external shape of the measuring instrument is only 3 mm wide.
It has been confirmed that it can be set to a length of approximately 8 cm, a length of approximately 8 cm, and a thickness of approximately 5 cm.

[Effects of the Invention] As explained above, according to the present invention, a person's height can be completely automatically measured just by standing on the measuring table, and the height can be automatically corrected for various errors.・It has remarkable effects such as eliminating the need for an arithmetic circuit, being lightweight and compact, and making it easy to attach and install the ultrasonic transmitting part.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention, FIGS.
This figure is an explanatory diagram showing an example of a circuit that implements the signal processing shown in FIG. 4, and FIG. 6 is an explanatory diagram showing a problem with a conventional height measuring device. DESCRIPTION OF SYMBOLS 1... Oscillator, 2... Timing generation circuit, 3... Transmission gate, 4... Switching circuit, 5... Ultrasonic oscillator, 6... Receiver, 7... Charge/discharge circuit, 8... Differential amplifier, 9... Decoder, 10... Addition/subtraction counter, 11... Display unit, 16... Buzzer, 17... Control circuit, 18... Person presence/absence determination circuit, 19... Temperature correction element, 20... Battery.

Claims (1)

[Claims] 1. A transmitter that intermittently generates ultrasonic waves, a receiver that receives reflected waves of the ultrasonic waves, a presence/absence determination circuit that generates a presence/absence signal of a person to be measured based on the output of the receiver, and a person to be measured. After the ultrasonic waves reflected from the person's head enter the receiver, a signal generator is provided to notify the person to leave the measurement table, and a delayed signal is generated by delaying the presence/absence signal by a predetermined period of time. A transmission synchronization signal that rises in synchronization with the transmission of the first ultrasonic wave after the rise and falls in synchronization with the transmission of the first ultrasonic wave after the fall of the delayed signal, and the first reception wave after the rise of the transmission synchronization signal. A control circuit that generates a reception synchronization signal that rises in synchronization with and falls in synchronization with the first received wave after the fall of the transmission synchronization signal, and subtracts from the time difference between the rises of the transmission synchronization signal and the reception synchronization signal. A decoder that creates a pulse gate and creates an addition pulse gate from the time difference between the falling edges of the transmission synchronization signal and the reception synchronization signal, and adds and subtracts a subtraction pulse based on the subtraction pulse gate and an addition pulse based on the addition pulse gate. An ultrasonic automatic height measuring device characterized by comprising an addition/subtraction counter.