JP3044518B2 - Human body detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type human body detecting device of an intermittent light projection type, and more particularly to a human body detecting device which outputs a detection signal to, for example, a water supply control device to control valve opening.

[0002]

2. Description of the Related Art Conventionally, a reflection-type human body detecting device for outputting a human body detecting signal to a water supply control device or the like has been disclosed in Japanese Patent Application Laid-Open No. 61-29.
Japanese Patent No. 4032 discloses comparing a light reception value with a threshold value and outputting a human body detection signal when the light reception value reaches the threshold value. Further, in the case of a reflection type human body detection device that is often used, the light reception value is integrated, the integrated value is compared with a threshold value, and a human body detection signal is output when the integrated value reaches the threshold value. Things. Further, the reflection type human body detection device described in Japanese Patent Application Laid-Open No. 5-156686 integrates a light reception value during light emission, compares the integrated value with a threshold value, and sets the integrated value to a threshold value. When it reaches, it outputs a human body detection signal.

[0003]

The above-mentioned first conventional reflection type human body detection device outputs a human body detection signal when the received light value reaches a threshold value. In such a case, there is a problem that a human body detection signal is output. Also, the second conventional reflection type human body detection device outputs a human body detection signal when the integrated light reception value reaches a threshold value. However, there is a problem that an incorrect human body detection signal is output. Further, since the third conventional reflection type human body detection device integrates the received light value during light emission and outputs a human body detection signal when the integrated value reaches a threshold value, Meanwhile, there is a problem that the human body detection signal is output even when the integrated value when the disturbance light is received reaches the threshold value.

Therefore, in the present invention, in a reflection type human body detecting device of an intermittent light projection type, a variation in light reception at the time of light projection is taken out.
This is held until the next light emission timing, and at the next light emission, the received light variation is extracted and updated, and the value obtained by integrating the received light variation within a certain period of time is compared with a threshold, and the integrated value is calculated. It is an object of the present invention to solve the problem of accurately detecting a human body by outputting a human body detection signal when a threshold value is reached.

[0005]

Technical means for solving the above problems include a light emitting element, a light receiving element, a light emitting pulse generating circuit for intermittently projecting light from the light emitting element, and an intermittent light projecting means for detecting an object to be detected. When the reflected light reflected by the light receiving element is received by the light receiving element, it is a reflection type human body detecting device that processes a light receiving signal output from the light receiving element and detects an object to be detected. An output conversion circuit that outputs a fluctuation value of a light receiving signal from the light receiving element only when light emission from the light emitting element is started in synchronization with the intermittent light emission timing and does not output the fluctuation value except at the time, and an integration circuit that integrates the fluctuation value And a determination means for outputting a detection signal of the detected object when the output value of the integration circuit reaches a preset threshold value.

[0006]

According to the human body detecting device having the above structure, at the time when light emission from the light emitting element is started in synchronization with the intermittent light emission timing by the light emitting pulse generating circuit, the light reflected by the object is reflected by the light receiving element. When the light is received by the output conversion circuit, the output conversion circuit outputs the fluctuation value of the light reception signal only at a short instant, so that the fluctuation value becomes a value excluding the influence of disturbance light and the like, and the fluctuation value is integrated by the integration circuit. Therefore, when the output value of the integration circuit reaches a preset threshold value, the determination means outputs a detection signal of the detected object.

[0007]

Next, embodiments of the present invention will be described. FIG.
FIG. 4 is a block diagram showing a first embodiment, and is a block diagram showing a configuration of a reflection-type human body detection device that outputs a human body detection signal to a water supply control device. FIG. 2 is a human body detection timing chart. As shown in FIG. 1, a light emitting pulse generating circuit 2 is provided which receives a light emission instruction from the microcomputer 1 and controls the transistor Q to be turned on and off. As shown in FIG. TA1
As shown in FIG. 2B, the light emitting element D1 composed of a light emitting diode or the like is turned on by switching on the transistor Q at an interval of, for example, two seconds from the light emitting pulse generating circuit 2 as shown in FIG. A light emission pulse to be output is output.
Since the transistor Q is turned on every time the light emission pulse is input to the base of the transistor Q,
A current is supplied from the power supply VB to the light emitting element D1, and the light emitting element D1 emits light intermittently at intervals of 2 seconds.

When light emitted from the light emitting element D1 is reflected by a human body (not shown), the reflected light is received by a light receiving element D2 comprising a light receiving diode or the like. When the light receiving element D2 receives the light, a light receiving voltage is output from the light receiving element D2 at a timing as shown in FIG. This received light voltage is applied to the amplifier A and is amplified by the amplifier A. The amplified light receiving voltage is applied to the capacitor C1 connected to the output side of the amplifier A, and is differentiated when the capacitor C1 is energized. That is, the voltage corresponding to the light receiving variation is output from the capacitor C1 as the light receiving voltage by the light receiving element D2.

The output side of the capacitor C1 is connected to switches S1 and S2 which are controlled to be opened and closed by the light emitting pulse generating circuit 2 in synchronization with the on and off timings of the light emitting pulses of the light emitting pulse generating circuit 2. ing. As shown in FIG. 2D, the switch S1 is controlled to be turned off for a short time in synchronization with the turning on of the light emission pulse, while the switch S2 is turned off as shown in FIG. Is controlled to be turned on for a very short time in synchronization with turning on. Therefore, the switch S2 is controlled to be turned on for a very short time in synchronization with the light emission pulse being turned on. Therefore, the light receiving voltage output from the capacitor C1 is connected to the operational amplifier OP1 and the capacitor via the resistor R during this very on time. And C2. The integrating circuit 3 converts the received light voltage input while the switch S2 is controlled to be on for a very short time as shown in FIG.
Integrate four times as shown in (f).

On the other hand, the switch S1 is controlled to be ON for a very short time in synchronization with the OFF timing of the light emission pulse from the light emission pulse generation circuit 2, and the charge stored in the capacitor C1 in preparation for the next light reception timing. To discharge.

A reset circuit 4 is connected to the output side of the integration circuit 3, and the integrated value of the integration circuit 3 is held until the reset circuit 4 performs a reset operation. Then, the integration value is output from the integration circuit 3 to the comparison circuit 5 including the operational amplifier OP2 and the threshold voltage source E1.

The comparison circuit 5 outputs a judgment signal for judging the detection of a human body as shown in FIG. 2 (g) at the moment when the integrated value reaches the set voltage of the threshold voltage source E1. Then, the determination signal is output to the water supply control means 6 to control the water supply valve 7 to be opened for a predetermined time.

In the above-described human body detecting operation, when noise N1 due to disturbance light is output from the light receiving element D2, as shown in FIG. 2C, the switch S1 is turned on (switch S2 Is off), and therefore is not integrated. Further, when the noise N2 due to other disturbance light is output, the generation timing of the noise N2 is not integrated because the reset circuit 4 is performing the reset operation. Further, when the noise N3 occurs, the generation timing of the noise N3 is not integrated because the switch S1 is on (the switch S2 is off). Accordingly, since noise caused by sudden disturbance light is hardly integrated, accurate human body detection not affected by disturbance light can be performed.

FIG. 3 is a block diagram in which the integrating circuit 3 and the comparing circuit 5 in FIG. 1 are constituted by a microcomputer. In this microcomputer, while the integrating circuit 3 and the comparing circuit 5 perform analog processing, an adding / subtracting logic 8 for digitally adding / subtracting the received light voltage output from the switch S2 and a predetermined time t are provided. It has a built-in comparison logic 9 for outputting a judgment signal for judging the detection of a human body when the addition / subtraction value reaches a predetermined value, and other configurations and operations are the same as those in FIG.

Next, a second embodiment will be described with reference to FIG. This second embodiment is not shown, but the first
A light emitting system similar to that of the embodiment is provided. That is, as described above, the light emitting pulse generating circuit 2 for controlling the transistor Q to be turned on and off in response to the light emission instruction from the microcomputer 1 is provided. The light pulse generation circuit 2 outputs a light emission pulse for switching on the transistor Q at an interval of, for example, two seconds and causing the light emitting element D1 to emit light. Since the transistor Q is switched on every time the light emission pulse is input to the base of the transistor Q, the light emitting element D1 emits light intermittently at an interval of 2 seconds.

On the other hand, the light intermittently emitted from the light emitting element D1 is a light receiving element for receiving the reflected light reflected by the human body.
Semiconductor position detection element PSD (Position Sensitive Photo
Detector). This semiconductor position detecting element P
SD is a sensor that measures the distance to the human body based on the principle of triangulation. Specifically, at the time of light reception, each of the two voltages V1 and V2 output from the both terminals of the semiconductor position detecting element PSD or the common terminal is amplified by each amplifier A with the same amplification. This amplified light receiving voltage is applied to each amplifier A
And is differentiated when the capacitor C1 is energized. That is, a voltage corresponding to the variation of the light received by the semiconductor position detection element PSD is output from each capacitor C1 as a received light voltage.

Connected to the output side of each capacitor C1 are switches S1 and S2 that are controlled to be opened and closed by the light emitting pulse generating circuit 2 in synchronization with the on and off timings of the light emitting pulse of the light emitting pulse generating circuit 2. Have been. The switch S1 is controlled to be turned off for a short time in synchronization with the turning on of the light emission pulse, while the switch S2 is controlled to be turned on for a short time in synchronization with the turning on of the light emission pulse. Therefore, the two switches S2 are controlled to be turned on for a very short time in synchronization with the light emission pulse being turned on. Therefore, the light receiving voltage output from each capacitor C1 is supplied to the operational amplifier via the resistor R during this very on time. It is input to two integrating circuits 3 composed of OP1 and capacitor C2. Then, each integrating circuit 3 integrates the received light voltage input while the switch S2 is controlled to be on for a short time.

The output side of each integrating circuit 3 has a sample hose.
The ground circuit S / H is connected. Two sample hoses
The hold circuit S / H samples the integration value output from each integration circuit 3, holds the value, and outputs the value to the comparison logic circuit 10 at the same timing. Note that the comparison logic circuit 10 may use a comparator constituted by an operational amplifier. The comparison logic circuit 10 calculates the distance between the human body and the semiconductor position detecting element PSD by calculating the ratio of the value (integral value) output from each of the two sample hold circuits S / H. When the distance is equal to or less than a predetermined value, a determination signal for determining detection of a human body is output. This determination signal is output to the water supply control means 6 similar to that of the first embodiment, and controls to open the water supply valve 7 for a predetermined time.

[0019]

As described above, according to the present invention, at the time when light emission from the light emitting element is started in synchronization with the intermittent light emission timing by the light emitting pulse generating circuit, the light reflected by the object to be detected. When the light is received by the light receiving element, the output conversion circuit outputs the fluctuation value of the light reception signal only at a short moment, so that the fluctuation value is a value excluding the influence of disturbance light and the like, and the fluctuation value at the initial light projection time Is integrated by the integration circuit, and when the output value of the integration circuit reaches a preset threshold value, the determination means outputs a detection signal of the object to be detected. Thus, there is an effect that a human body can be reliably detected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a timing chart of human body detection.

FIG. 3 is a block diagram showing a partial modification of FIG. 1;

FIG. 4 is a block diagram showing a configuration of a main part of a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microcomputer 2 Light emission pulse generation circuit 3 Integration circuit 4 Reset circuit 5 Comparison circuit 8 Addition / subtraction logic 9 Comparison logic 10 Comparison logic circuit D1 Light emitting element D2 Light receiving element Q Transistor A Amplifier C1 Capacitor S1 Switch S2 Switch PSD Semiconductor position detection element

Claims (1)

(57) [Claims] A light emitting element; a light receiving element; a light emitting pulse generating circuit for intermittently projecting light from the light emitting element; A reflection-type human body detection device that processes a light-receiving signal output from a light-receiving element and detects an object to be detected, wherein light emission starts from the light-emitting element in synchronization with intermittent light emission timing by the light emission pulse generation circuit. An output conversion circuit that outputs a variation value of the light receiving signal from the light receiving element only at the time when the variation is detected and does not output the variation value other than the time, an integration circuit that integrates the variation value, and a threshold value at which the output value of the integration circuit is set in advance. A human body detection device comprising: a determination unit that outputs a detection signal of the detected object when the value reaches a value.