JPH0122912B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic door activation switch using a microwave Doppler signal sensor.

By the way, when we look at the entrances and exits of modern buildings, etc., in many cases they are almost always used as emergency exits, and the same is true for places where automatic doors are installed. FIG. 1 is a diagram showing the situation. For example, there is a marking light 3 on the ceiling 2 near the automatic door 1 that says "Emergency Exit".
is suspended, and a detection device for the automatic door 1 is buried under the floor 4. When a passerby 5 approaches or leaves the automatic door 1, the detection device detects this and automatically opens and closes the automatic door 1.

Further, there is a microwave Doppler signal sensor as a detection device that is attached to the ceiling 2, but a detection device for an automatic door using a microwave Doppler signal sensor has the following drawbacks. That is, if a lighting fixture such as a fluorescent lamp that uses discharge exists within the detection area, this may be input and malfunction may occur. For example, as shown in FIG. 2, an indicator light 11 is hung immediately near the door 10,
If the show case 12 is placed nearby, the discharge spectrum will be different from the microwave Doppler signal sensor 13 and the light source of this type of indicator light 11 and show case 12, since a fluorescent lamp is often used as the light source. 14, the switch circuit operates,
The door 10 may be left open. For this reason, in the past, the sensors 13 and 14 were moved to prevent these lights from entering.

However, if it is known that something malfunctioning like this is nearby, such countermeasures can be taken in advance. There are many. Therefore, even if countermeasures have been taken in the design, after installation, the adjacent fluorescent lamp 15 may reflect off the open metal cover 16, etc., causing unexpected malfunction.
In some cases, the sensor cannot be installed on-site and the sensor ends up being replaced with another one.

Next, a detection circuit using a microwave Doppler signal sensor is shown in FIG. 3, and its operation will be explained.The microwave Doppler signal sensor 20 includes a Gunn oscillator that outputs a fundamental wave _f0 . In addition, a mixer diode is incorporated that homodyne detects the fundamental wave f ₀ and the microwave f ₁ that is emitted and modulated and reflected by passersby.
A Doppler signal DS of |f ₀ −f ₁ | is output to the output side.
This Doppler signal DS is a low frequency signal of several Hz to several KHz, and is inputted to a bandpass filter 21 via a capacitor _C1 , and only frequencies within an appropriate bandwidth are extracted. Then, it is applied to one input of a comparator 24 via an amplifier 22 and a detector 23,
The relay 25 is activated via the transistor _Q1 by comparing it with a reference voltage inputted to the other side.

On the other hand, the signal coming from the fluorescent lamp (here, it is assumed to be a detected signal similar to the Doppler signal) is synchronized with the power supply (commercial) frequency as shown in Fig. 4A and B.
Although the waveform varies depending on the incident state of the radio waves, the waveform remains the same as long as the incident state does not change. Different waveforms are maintained in the positive half cycle and the negative half cycle, and in order to reduce the influence of the fluorescent light from this waveform, it is conceivable to remove it with the filter 21. That is, since the frequency of the above waveform is generated around 100 Hz or 120 Hz, the filter 21 removes the frequency around 100 to 120 Hz. However, with this type of automatic door detection circuit, the Doppler signal when a passerby approaches on foot normally does not have to reach the upper limit of 100 Hz, which is still within the practical range. However, in cases where a fluorescent light signal is directly input, the signal is much larger than the Doppler signal of a passerby, so the current situation is that the influence cannot be completely eliminated. If the influence is forcibly eliminated, a problem will occur in the Doppler signal band where passersby are walking, resulting in poor operating sensitivity.
There are filters that rapidly remove frequencies around 100 to 120 Hz, but they have the drawback of being extremely expensive.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an automatic door activation switch that does not have the above-mentioned drawbacks.

This invention will be explained below.

The present invention relates to an automatic door activation switch using a microwave Doppler signal sensor, and as shown in FIG.
C ₄ and a high impedance voltage follower 31, and the analog switch 30 is connected to a synchronous pulse synchronized with the power supply frequency from a pulse generator 32.
The Doppler signal DS is sampled by on/off control by the SP, and the sampled output HS is held by the capacitor _C4 and inputted to the high impedance voltage follower 31 to perform the required detection. However, the synchronization pulse
SP is output from the monostable multi (one shot multi) 321 of the pulse generator 32, and its pulse width is determined by the resistor _R1 and the capacitor.
It is determined by the time constant R ₁ · C ₇ due to C ₇ , but it is adjusted to be as narrow as possible. Then, when the synchronization pulse SP is output, the analog switch 30
is turned on, the Doppler signal DS is applied to the capacitor _C4 via the analog switch 30, and this level is applied to the capacitor _C4 until the next synchronization pulse SP arrives.
The high impedance voltage follower 31 is used to maintain the voltage so that it does not discharge. An example of such an operation is the sixth
As shown in Figs. The level of C) is maintained as shown in D of the figure. Then, this holding voltage is outputted as a gradual level change signal HSA as shown in FIG. Since the waveforms are the same, the Doppler signal DS can be controlled using pulses synchronized with this.
The waveform is almost the same as that obtained by adding or subtracting a certain level. Therefore, by filtering this signal HSA to extract an appropriate bandwidth, detecting the level, and activating the relay, the fluorescent lamp signal (dotted line in Figure 6 C) is completely passed through. becomes. Note that the pulse SP for sampling only needs to be synchronized with the power supply frequency, and the phase may be selected appropriately. However, it is necessary to sample only the positive half cycle or the negative half cycle of the fluorescent lamp, and it makes no sense to mix the positive and negative half cycles because the positive and negative half cycles of the fluorescent lamp often have different waveforms. There is no.

As described above, the automatic door activation switch of the present invention samples the Doppler signal from the microwave Doppler signal sensor with a pulse synchronized with the noise signal even if it is output superimposed on the noise signal from a fluorescent light or the like. By maintaining that level until the next pulse and outputting it, the output is arranged into a waveform characteristic that is a Doppler signal with a certain level added or subtracted, so only the desired Doppler signal can be detected accurately. can do. This works effectively against all unforeseen noise signals in the detection area, and has the advantage of providing a highly accurate function with fewer malfunctions as an automatic door start switch.

[Brief explanation of drawings]

Figure 1 is a diagram showing the situation near the emergency exit of a building, etc. Figure 2 is an explanatory diagram showing the installation state of a detection device using a microwave Doppler signal sensor, and Figure 3 is an illustration of a detection circuit using a microwave Doppler signal sensor. A circuit diagram showing an example; FIGS. 4A and B are time charts showing an example of a signal waveform of a fluorescent lamp; FIG. 5 is a circuit configuration diagram showing an embodiment of the present invention; FIGS. 6A to E
is a time chart showing an example of its operation. 1... Automatic door, 3, 11... Signal light, 10...
... Door, 13, 14, 20 ... Microwave Doppler signal sensor, 21 ... Filter, 25 ... Relay, 30 ... Analog switch, 31 ... High impedance voltage follower, 32 ... Pulse generator.

Claims (1)

[Claims] 1. A microwave Doppler signal sensor incorporating a Gunn oscillator that outputs and radiates a continuous fundamental wave and a mixer diode that homodyne-detects the modulated and reflected microwave of the emitted continuous fundamental wave with respect to the continuous fundamental wave. an analog switch for inputting the homodyne-detected Doppler signal, a pulse generating means for controlling the analog switch on and off with a synchronization pulse synchronized with the power supply frequency, and a capacitor for holding the output of the analog switch; 1. A starting switch for an automatic door, comprising: a high impedance voltage follower into which a holding signal of a capacitor is input; and opening/closing of the automatic door is controlled by the output of the high impedance voltage follower.