JPS5880576A - Object detecting device - Google Patents

Abstract

PURPOSE:To improve handling of the titled device, by continuing the operation of the device when no received signal exists in an ultrasonic wave receiver during a gate opening period after the generation of a ultrasonic pulse is stopped, but stopping the device when a noise is detected. CONSTITUTION:An ultrasonic wave sent from an ultrasonic wave transmitter 2 and reflected by an object 1 to be detected is received by a receiver 3 and applied to one input of an AND gate circuit 29. During the opening period of said gate, an output from an one-shot circuit 8 is inputted to the gate circuit 29, the output of the circuit 29 is inputted to a comparator 30 to compare it with a reference value and, when the output exceeds the reference value, it is inputted to an FF2 31. An output signal from the FF2 31 is inputted to an AND gate circuit 33, and a stopping circuit 7 to stop the generation of ultrasonic pulses. Since a signal is applied to the other input of the gate circuit 33, the output is sent to an output circuit 40. If the receiver 3 receives a signal during the opening period of the gate after the generation of ultrasonic wave is stopped, the gate circuit 35 is not actuated and the output circuit 40 stops outputting. Consequently, the device can be easily handled.

Description

Detailed Description of the Invention The present invention is an object that detects the presence of an object by transmitting ultrasonic pulses to a predetermined space using an ultrasonic transmitter and receiving the reflected waves using an ultrasonic receiver. The present invention relates to a detection device, and particularly to an object detection device that requires few operations and is easy to use.

An embodiment of the object detection device of the present invention will be described below with reference to the drawings.

The object detection device of the present invention is configured as shown in FIG. 1, in which 1 indicates an object to be detected such as a human body;
2 is an ultrasonic transmitter that transmits (emits, transmits) an ultrasonic pulse signal; 3 is an ultrasonic receiver; 4 is a drive circuit for the ultrasonic transmitter 2; 5 is an AND gate circuit; and 6 is an Relatively high wave oscillator (hereinafter referred to as OSC) for generating ultrasonic signals, 7
8 is a stop circuit for stopping the emission of the next ultrasonic pulse when the ultrasonic receiver 3 has a certain reception signal during the gate opening period after transmitting the ultrasonic pulse; 8 is a one-shot circuit; 9 1 is a relatively low-frequency oscillator (hereinafter referred to as 08C2) that determines the period of transmission of ultrasonic pulses, 10 is a differentiating circuit, and 11 is a holding circuit for inputting and holding an ultrasonic pulse signal for a certain period of time ( (hereinafter referred to as FF), 12 is a not gate circuit, 13 is a differentiating circuit, 14 is a not gate circuit, 15
is a not gate circuit, 16 is a resistor, 17.18 is a comparator, 19 to 22 are resistors, 23 is a capacitor, 24
．． 25 is a resistor, 26 is an NPN) transistor, and 27 is a resistor, and the circuits and elements indicated by the above-mentioned numerals 15 to 27 constitute a timing circuit that sets the gate opening period, that is, the detection distance range of the detected object l. . 28 is an amplification circuit (A) that amplifies the ultrasound signal received by the ultrasound receiver 3;
MP), 29 is an AND gate circuit, and 30 is a comparison circuit (CO
M), 31 is a holding circuit (hereinafter abbreviated as FF2) for inputting the output signal of the comparison circuit 30 and holding it for a certain period of time, 82.3
8 is an AND gate circuit; 34 is a no-signal detection circuit that outputs a signal when the ultrasonic receiver 3 does not receive a certain signal during the gate opening period after stopping the ultrasonic pulse; 35 is an AND gate circuit; 36 is a holding circuit (hereinafter F
37 is a clear signal generation circuit for clearing the FF 336, 38 is an AND gate circuit, and 39 is a final signal, that is, a certain received signal exists during the gate opening period after transmitting the ultrasonic pulse signal. In addition, a holding circuit (hereinafter referred to as FF4) for inputting a signal generated when a certain received signal does not exist during the gate opening period after the ultrasonic pulse stops and holding it for a certain period of time (hereinafter referred to as FF4), 40 is an external load such as a switch. This is a circuit for controlling according to the presence (presence or absence) of the detected object 1.

08C29 is connected to one input of the AND gate circuit 5 via the one-shot circuit 8, O5C, 6 is connected to the other input, and the output of the AND gate circuit 5 is input to the drive circuit 4. The output of the drive circuit 4 is connected to the ultrasonic transmitter 2.

Rumor The output of the above AND gate circuit 5 is further connected to the input of FF 11, and the output of FF 11 is connected to the AND gate circuit 3.
Further, the output of the FF 11 is connected to the input of a NOT gate circuit 14, and the output of the NOT gate circuit 14 is connected to one input of an AND gate circuit 32.

The output of the one-shot circuit 8 is connected to the input of a differentiating circuit 10, and the output of the differentiating circuit 10 is connected to the clear input of F',11. Further, the output of the one-shot circuit 8 is connected to the input of the not gate circuit 12, the output of the not gate circuit 12 is connected to the input of the differentiating circuit 18, and the output of the differentiating circuit 13 is connected to the clear input of FF2:II1. It is connected. Furthermore, the output of the one-shot circuit 8 is connected via a resistor 27 of the timing circuit to the base of the transistor 26 and to the input of the not gate circuit 15. The output of the not gate circuit 15 is connected to the output terminals of comparators 17 and 18 via a resistor 16 (comparators 17 and 18 are connected to wired OR), and the outputs of these gate circuits 17 and 18 are connected to the AND It is connected to the other input of the gate circuit 32 and one input of the AND gate circuit 29 . The comparator 1
7 and the connector (18) are short-circuited, a capacitor 23 is connected between this connection end and the nurse, and the connection end is connected to the DC power supply (+Vcc) via a resistor 24.
Furthermore, it is connected to the collector of a transistor 26 via a resistor 25. Further, the emitter of the transistor 26 is connected to ground. The power of the comparator 17 is connected to the connection end of the resistor 19 and 20 connected in series between the DC power supply (+Vcc) and the ground.
8's single power is DC power supply (+Vcc).

It is connected to the connecting end of a resistor 21, 22 which is DC connected between the ground.

Further, the ultrasonic receiver 3 is connected to the input of the amplifier circuit 28,
The output of the amplifier circuit 28 is connected to the other input of the AND gate circuit 29, the output of the AND gate circuit 29 is connected to the input of the comparison circuit 30, and the output of the comparison circuit 30 is connected to the other input of the AND gate circuit 29.
Connected to the input of F231. The output of the FF 231 is connected to the other input of the AND gate circuit 33 and further connected to the stop circuit 7, and the output of the stop circuit 7 is connected to O5C,6. The output of the AND gate circuit 88 is connected to the FF8860 input, and the FF83
The output of the FF 886 is connected to one input of the AND gate circuit 38, and the output of the clear signal generation circuit 87 is connected to the clear input of the FF 886.

Further, the output of the AND gate circuit 82 is connected to one input of an AND gate circuit 85, the output of the no-signal detection circuit 34 is connected to the other input, and the output of the AND gate circuit 35 is connected to the output of the AND gate circuit 88. connected to the other input. The input of the AND gate circuit 88 is FF4
The output of the FF 489 is connected to the input of the output circuit 40.

In FIGS. 2 (G) and (B), A is the output waveform of O5C, 6, mouth is the output waveform of the one-shot circuit 8, C is the output waveform of the AND gate circuit 5, and 2 is the output waveform of the NOT gate circuit 15. , E are the charging and discharging waveforms of the capacitor 23, and the two threshold values d1. The comparators 17 and 18 operate according to d2, and when the outputs of both comparators 17 and 18 become high (high level), the window comparator toggles and outputs. is the output waveform of the comparators 17 and 18 (window comparators), and α is the gate opening period. G is the output waveform of the amplifier circuit 28, H is the output waveform of the FF, 11 is the output waveform of the NOT gate circuit 14, N is the output waveform of the FF 281, R is the output waveform of the AND gate circuit 35, W is the FF
886, wa is the output waveform of the clear signal generation circuit 37, and y is the output waveform of the AND gate circuit 38.

FIG. 2(B) shows the signal waveforms of the main parts when the detected object 1 is not present, and FIG. 2(B) shows the signal waveforms of the main parts when the detected object 1 is present.

Next, the operating state of the object detection device configured as described above will be explained.

First, the signal as shown in Figure 2 prisoner A from O5C, 6 and the signal shown in Figure 2 prisoner's mouth from 08C29 and the one-shot circuit 8 are processed by the AND gate circuit 5, and the signal shown in Figure 2 prisoner's mouth is processed by the AND gate circuit 5. The signal is applied to the ultrasonic transmitter 2 via the drive circuit 4 as a signal as shown in FIG. However, when the detected object 1 exists, the reflected signal of the ultrasonic pulse is received by the ultrasonic receiver 8 and amplified by the amplifier circuit 28, resulting in a signal as shown in (6) in FIG. If the 0 outputted from the amplifier circuit 28 and inputted to one input of the AND gate circuit 29 is during the output of the timing circuit, that is, during the gate open period, then the timing is as shown in FIG. 2 (6). It is also input to the other input of the AND gate circuit 29 as a signal as shown, and the output of the AND gate circuit 29 is output and input to the comparison circuit 30. By the way, the operation mode of the above-mentioned timing circuit is that while the one-shot circuit 8 is outputting, the charge of the capacitor 28 is discharged through the microresistance 25 and the transistor 26, but when the output of the one-shot circuit 8 becomes low (low level), the capacitor 28 is discharged. 28 is charged from the DC power supply (+Vcc) via the resistor 24 and has a potential as shown in FIG. 2E. From the beginning of charging to the threshold value of γ2, comparator 17 is high (
The comparator 18 outputs a high (high level) output until γ, and the comparator 18 outputs a high (high level) output. Therefore, since comparators 17 and 18 are connected to wired OR, both comparators 17 and 18 are high ().
The output as shown in FIG. 2 is output only during the period α during which the output (Irepel) is output. Further, the threshold values γ1 and γ2 are determined by the resistors 21, 22, and 19.20.

Furthermore, when the capacitor 23 is discharged, γ1. Although there is a threshold value of γ2, since the not gate circuit 15 supplies power to the pull-up resistor 16 only when the capacitor 23 is being charged, no output from the window comparator is produced when the capacitor 23 is being discharged.

Then, as described above, when the input signal is input to the comparator circuit 30, it is compared with the reference signal, and if the received signal level is higher than the reference signal level, the comparator circuit 30 outputs the signal, and the FF 211 is input, and the signal shown in FIG. 2(B) is output. This output signal is applied to one input of the AND gate circuit 33 and the stop circuit 7, and the stop circuit 7 operates (trying to stop emitting the primary ultrasonic pulse). .

When the ultrasonic pulse is transmitted as described above, that is, the output of the AND gate circuit 5 is applied to the input of the FF 11, and the clear signal at the rising edge of the next one shot (this is the differential circuit 10) is applied to the input of the FF 11. The output of FF 11 is held until it is cleared by (formed by The output of the gate circuit 33 outputs a signal, and therefore, the output of the FF 836 remains as shown in FIG. 2(B) until there is a clear signal generated by the clear signal generating circuit 37 as shown in FIG. It is held as shown in .

Further, if the O5C and 6 do not operate due to the operation of the stop circuit 7, the next ultrasonic pulse will not be emitted, as shown in the signal shown by C in FIG. 2(B). Then, there is no input to FF and 11, so F
The output of F and 11 becomes low (low level) as shown in Figure 2 (B), and the inverted output by the not gate circuit 14 becomes a high (high level) signal as shown in Figure 2 (B). becomes. The signal is input to one input of the AND gate circuit 32, and the output of a timing circuit (window comparator) is input to the other input of the AND gate circuit 32, and a constant signal is sent at the same period regardless of the presence or absence of ultrasonic pulses. Since the output is continuously applied and 0'S is applied, the output signal of the AND gate circuit 32 is outputted and inputted to one input of the AND gate circuit 35. If there is no constant reception signal in the ultrasonic receiver 3 during the gate opening period after the ultrasonic pulse stops (unless there is noise etc., there is no reception signal during this gate opening period), the no-signal detection circuit 34 An output signal is output from the AND gate circuit 35 and applied to the other input of the AND gate circuit 35.

Then, the output signal of the AND gate circuit 35 is as shown in FIG.
), and the output signal is applied to the other input of the AND gate circuit 38.The output signal is applied to the other input of the AND gate circuit 38.
Since the signal shown in 3) is inputted, the AND gate circuit 38 outputs the signal shown in FIG. 2(B) and applies it to the input of the FF 439. The output of the FF 489 is held for a certain period of time and applied to the input of the output circuit 40,
The operation of the output circuit 401 causes external loads such as switches (
(omitted) is controlled.

Furthermore, if the detected object 1 does not exist, the output signal of the amplifier circuit 28 does not exist as shown in (8) in FIG. ), the output circuit 4 does not operate.

Furthermore, even if a received signal exists during the gate open period after ultrasonic pulse transmission, if a received signal exists during the gate open period after the ultrasonic pulse stops, the output signal of the no-signal detection circuit 84 will not be output. Therefore, the output signal of the AND gate circuit 35 and the output signal of the AND gate circuit 38 do not exist, and the output circuit 40 does not operate.

Since the object detection device of the present invention has the above configuration,
As long as there is no reception signal in the ultrasonic receiver periodically during the gate opening period, the object detection device according to the present invention operates,
Since the configuration does not detect all noise and always stop operation due to the presence of noise, it has the advantage of being very easy to use.

[Brief explanation of the drawing]

1m', 4) A schematic block diagram showing an embodiment of the object detection device of the present invention, and FIG. 2 is a waveform diagram of each part of FIG. 1. In the drawings, 1 indicates an object to be detected, 2 an ultrasonic transmitter, and 8 an ultrasonic receiver. Agent Patent Attorney Fukushi Aihikoru□ Wa□ 〃−−−−−−−−−−−−−−−−−−−−
A) (B)

Claims (1)

[Claims] 1. In an object detection device that detects the presence of an object by transmitting an ultrasonic pulse to a predetermined space using an ultrasonic transmitter and receiving the reflected wave by an ultrasonic receiver, stopping means for stopping the transmission of ultrasonic pulses from the ultrasonic transmitter for a certain period of time when a certain signal is received by the ultrasonic receiver; and a wave transmitting means for transmitting a wave signal, and when the wave transmitting means transmits a wave signal, a certain gate opening period is provided after transmitting the ultrasonic pulse and after stopping the ultrasonic pulse to receive the ultrasonic signal. and a means for making the opening time of both the gate opening periods after the ultrasonic pulse is transmitted and after the ultrasonic pulse is stopped, when the wave period is set as the wave period, and detecting the presence of an object to be detected. Device.