JPH0447876B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an infrared warning device, and an object of the present invention is to eliminate all false alarms from the warning device and obtain a highly reliable warning device. As a conventionally known infrared warning device, a plurality of sets of transmitters that emit infrared rays and receivers that receive the infrared rays are arranged in parallel, facing each other, and a warning range close to a fence-like plane is covered with a plurality of infrared rays. There is something that has been formed. However, such infrared warning devices issue an alarm when only one infrared ray is blocked, and can be affected by small animals, birds, leaves, etc. other than intruders, for example. Therefore, the light-shielding response speed of the receiver was made relatively slow, ranging from several tens of milliseconds to several hundred milliseconds, to reduce false alarms. However, there are various factors that can cause false alarms, such as when a small animal stops in a state that blocks infrared light,
When a bird flies down in a direction parallel to the optical axis of the infrared rays, the infrared rays are blocked faster than the light blocking response speed, causing false alarms. Furthermore, if the light shielding response speed was too slow, if an intruder ran and passed through the warning range, the alarm would not be issued because humans run at a speed of about 7 to 8 m/sec. An object of the present invention is to provide a warning device that not only accurately reports the interruption of a beam of light by an intruder, but also eliminates false alarms by distinguishing the interruption of the beam of light by someone other than the intruder. There is a particular thing. To achieve this objective, the present invention is intended to issue a warning based on a combination of the number of infrared rays blocked and the duration of the cutoff, depending on the location and situation where the warning device is installed. Furthermore, the present invention provides a more reliable light beam warning device that can be set to always generate an alarm when infrared rays at a specific height are blocked depending on the situation. The purpose is to The present invention includes a light transmitter housing a plurality of light transmitting parts that emit pulsed infrared rays, and a light receiver housing a plurality of light receiving parts that respectively receive the infrared rays, which are installed facing each other across a warning zone. A light-beam warning system consisting of the above light transmitter and light receiver, each of which has a light transmitting section and a light receiving section coupled by a single infrared ray and operates as a pair, and which is coupled by a plurality of warning infrared rays as a whole. In the apparatus, a number of blocked rays detecting means is connected to the plurality of light receiving sections and detects the number of rays blocked within a minute predetermined time, and outputs a separate blocking signal for each number of blocked rays, and the number of blocked rays detecting means and a cutoff time detection means that is connected to each of the plurality of outputs and outputs an alarm signal when it detects that the input cutoff signal has continued for a minimum cutoff time required to issue an alarm, and detects the cutoff time. The light beam warning device is characterized in that the minimum interruption time of each of the means is set longer as the number of interruptions is smaller. According to the present invention, when the number of light rays blocked is large,
Since the alarm is issued for a short interruption time, or for a long interruption time if the number of beam interruptions is small, it is possible to accurately identify an intruder and issue an alarm. For example, when a person actually runs across a warning light beam, the light beam interruption time is short, about 30 to 50 msec.
Since the person is naturally in a standing position, many light beams will be blocked at the same time. On the other hand, if a person crouches or crawls to cross the light beam, the number of light beams blocked will decrease, but the amount of time they will be blocked will be longer. Also, as mentioned above, objects that block the warning light and cause false alarms can be birds, tree leaves, and small animals (cats, dogs, etc.), but these are generally smaller than humans. Therefore, compared to humans, the number of light beams blocked is small and the blocking time is shortened. Therefore, according to the present invention, it is possible to reliably distinguish an intruder from others and issue an alarm. However, depending on the actual installation location of such a device, the movement of an intruder may be restricted. For example, if it is impossible to run due to conditions such as a wall near the installation location or a large number of standing trees, there is no need to issue an alarm in response to a short interruption time. In order to eliminate false alarms, it is better to have a longer response time, so in such a case, it is convenient to make the minimum cut-off time set in the above-mentioned cut-off time detection means variable. Furthermore, depending on the installation location, a particular position of the plurality of warning infrared rays may have the highest probability of being blocked by an intruder. For example, if the device is used with barbed wire, the corresponding infrared radiation is most likely to be blocked between the lower tiers of barbed wire, or if installed close to a structure, the corresponding infrared radiation will be most likely to be blocked. There is a high probability that the infrared rays from above will be blocked by jumping off. In order to ensure vigilance in such cases, in addition to the above configuration, a specific light beam is installed that detects the interruption of infrared rays at a specific position and outputs an alarm signal when the interruption time is longer than a predetermined time. It is better to add a detection means. The alarm signals output from the plurality of cut-off time detection means described above are logically summed and added to one alarm generating device (bell, siren, etc.) as a starting signal to detect the presence of an intruder. It is possible to issue an audible alarm. In addition, in order to be able to take an alert state early, a plurality of (for example, two) cut-off time detection means are connected to each of the plurality of outputs of the cut-off ray number detection means,
Set the minimum cutoff time for each to be different.
The operation of the first cut-off time detection means may issue a warning, and the operation of the second cut-off time detection means may issue a warning. In addition to ranking such as advisories and warnings, it is also possible to estimate the obstruction itself as an intruder, bird, small animal, etc. and display it separately. Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the light transmitting/receiving section and the number of blocked rays detecting section. In Figure 1, 1 is an oscillator that selectively oscillates clock pulses in the range of several kHz to 100 kHz;
2 is a counter that adds and counts the clock pulses from oscillator 1 one by one, resets it to a predetermined value of n+1 or more, repeatedly counts, and outputs the counted value as a binary number; 10 (n of 10-1 to 10-n); 11 (showing the case of n pieces from 11-1 to 11-n) receives the infrared rays from the corresponding light transmitting unit. The light receiving section generates an H level signal when infrared rays are blocked. 3 is a multiplexer that sequentially selects one of the plurality of input signals from the light receiving section 11 as 4-1, 4-2, 4-3 based on the binary number generated from the counter 2; 5 is an AND circuit; 6 counts the output of the AND circuit 5, and uses the reset signal output of the counter 2, that is, the multiplexer 3 calculates the output signals 4-1 and 4 of the light receiving section 11.
After selecting the nth of -2, 4...n, the counter 7 (the case of m numbers from 7-1 to 7-m is shown) is read out and reset from the counter 6. This is a comparator that compares the input signal of the digital switch 8 with the numerical value set by the digital switch 8 (includes m digital switches 8-1 to 8-m) and outputs the result under certain conditions. 9 is a signal holding circuit that holds the output of the comparator 7 for a time corresponding to the time from the start of counting to the reset of the counter 2 (hereinafter referred to as one scanning period); There are m pieces of m. FIG. 2 is a block diagram showing a cutoff time detection section and an alarm generation section. In Figure 2, 12 is the first
A time detection circuit connected to the signal holding circuit 9 on the output side of the comparator 7 shown in the figure.
1,...,9-m, two each, namely 12-1, 12-1',..., 12-m, 12
−m′ is provided. This time detection circuit generates an output signal when the input signal continues for a period of time set therein. Time detection circuit 12-1, 12
-2,..., 12-m outputs from the first OR circuit 13
-1, and is connected to the input of the time detection circuit 12-1',
The outputs of 12-2', . . . , 12-m' are input to a second OR circuit 13-2. First OR circuit 1
Alarm generators 14-1 and 14-2 are connected to the outputs of 3-1 and the second OR circuit 13-2, respectively. Time detection circuit 12-1, 12-2,..., 12-
The times set in m are all different as described below, and each has a parallel 12-
1', 12-2', . . . , 12-m' are also set at different times. An example of these time detection circuits is shown in FIG. 3, and a waveform diagram of each part thereof is shown in FIG. Referring to FIGS. 3 and 4, when the signal shown in FIG. 4A is input from the output of the signal holding circuit 9 of FIG.
Then, the phase is inverted to produce a signal as shown in FIG. 4B, which is supplied to the charging capacitor 123 via the diode 122. capacitor 123
A discharge resistor 124 is connected in parallel with the inverter 1, which is controlled by the potential of the capacitor 123.
25 are connected. Therefore, capacitor 12
3 is normally charged to a level higher than the threshold level of the inverter 125, as shown in FIG. When the voltage falls below the voltage threshold level TH, an H level signal is selected from the inverter 125 as shown in FIG. 4D. Here, the time t until the output of the inverter 121 becomes H level and the voltage of the capacitor 123 falls to the TH level is determined by the time constant of the capacitor 123 and the resistor 124.
By appropriately selecting the value of 4, the minimum cut-off time of the corresponding detection circuit can be set. Of course, by making at least one of the capacitor 123 and the resistor 124 a variable resistor, the minimum cut-off time can be variably set as desired. In FIG. 3, the resistor 124 is shown as a semi-fixed resistor. Of course, for variable setting, a plurality of resistors with different resistance values may be provided and selectively connected using a switch. In the circuit as described above, first, the clock pulses of the oscillator 1 are counted by the counter 2, and the output to the multiplexer 3 is added by one for each clock pulse. As a result, the multiplexer 3 sequentially selects the input signals from the light receiving section 11 in accordance with the clock pulses of the counter 2. That is, when the output of counter 2 is n, multiplexer 3
will select input signal 4-n. Now, assuming that infrared rays are not blocked at all, the input signals 4 of the multiplexer 3 are all at L level, so no signal is generated from the multiplexer 3 and no signal is applied to the AND circuit 5. Therefore, the circuits after the AND circuit 5 do not operate and do not issue an alarm. Next, when the infrared rays are blocked by a shielding object,
The output signal of the corresponding light receiving section 11 becomes H level. Therefore, the multiplexer 3 sequentially selects the output signals of the light receiving section 11, and when a signal at H level is selected, the output of the multiplexer 3 also becomes H level, and the signal is input to the AND circuit 5. On the other hand, the clock pulse oscillated by the oscillator 1 emits an H level signal at regular intervals, and since the pulses are synchronized with the sequential selection of the output signals of the light receiving section 11, an H level multiplexer is added to the AND circuit. At the same time as the output of is added, an H level signal is also added from the oscillator 5, so a signal is output from the AND circuit 5 and applied to the counter 6. and,
Counter 6 counts input signals at H level,
The counted value is read out by the reset pulse from the counter 2 and sent to all the comparators 7, and the counter 6 is reset. At that time, each comparator 7 compares the input count value with the numerical value set by the corresponding digital switch 8, and if the two do not match, no signal is output from the comparator 7. Now, if the set value of digital switch 8-1 matches the input count value of comparator 7-1, then
1 to an H level signal is output, and this signal is held by the signal holding circuit 9-1 for one scanning cycle. Therefore, if the same number of infrared rays are blocked in the next scanning period, the output of the signal holding circuit 9-1 remains at the H level. In this way, as long as the number of infrared rays set by the digital switch 8-1 is blocked, the output of the signal holding circuit 9-1 is held at the H level. This also applies to other sets of comparators, digital switches, and signal holding circuits. Since the output of the signal holding circuit 9 is applied to the time detection circuit 12, if the H level output of the signal holding circuit 9 continues for a longer time than the time set by the time detection circuit 12, the time detection circuit 12 H
A level signal is sent out. This H level signal is applied to the alarm generator 14 through the OR circuit 13, drives the alarm generator 14, and generates an alarm. For example, as mentioned above, from the signal holding circuit 9-1
A level signal is generated, and its duration is
When the time is longer than the minimum cut-off time set by the time detection circuit 12-1', the H
A level signal is output, and the signal is OR circuit 1
3-2 to drive the alarm generating device 14-2. Furthermore, when the transmission time of the H level signal from the signal holding circuit 9-1 is longer than the minimum cutoff time set by the time detection circuit 12-1, an H level signal is output from the time detection circuit 12-1, and the signal is The alarm generating device 14-1 is driven via the OR circuit 13-1. Therefore, time detection circuits 12-1 and 12-
If the minimum cutoff time to be set to 1' is appropriately determined,
The alarm from the alarm generator 14-1 can be a main alarm, and the alarm from the alarm generator 14-2 can be a caution alarm. Of course, in this case, instead of ranking the warnings as described above, it is also possible to estimate whether the blocking object is a person, an island, or a small animal, and give different warnings. Other signal holding circuits 9-2,..., 9-m and time detection circuits 12-2, 12-2' connected thereto
The same applies to the operations of 12-m and 12-m'. The following table shows an example of the relationship between the signal from the comparator 7 corresponding to the number of cutoffs, that is, the number set by the digital switch, and the minimum cutoff time set in the corresponding time detection circuit.

【table】

Claims (1)

[Scope of Claims] 1. A light transmitter housing a plurality of light transmitting sections that emit pulsed infrared rays and a light receiver housing a plurality of light receiving sections that each receive the infrared rays are placed opposite to each other across a warning zone. When installed, each light transmitter and light receiver are coupled by one infrared ray and operate as a pair, and the whole is composed of the above light transmitter and light receiver coupled by a plurality of warning infrared rays. In the optical beam warning device, a number of blocked rays detecting means is connected to the plurality of light receiving units and detects the number of rays blocked within a minute fixed time, and outputs a separate blocking signal for each number of blocked rays, and the blocked rays a cutoff time detection means connected to each of the plurality of outputs of the number detection means, and outputs an alarm signal when the input cutoff signal continues for a minimum cutoff time required to issue an alarm; A light-ray alarm device characterized in that the minimum cut-off time of each of the cut-off time detection means is set to be longer as the number of cut-off rays is smaller. 2. A light transmitter housing a plurality of light transmitters that emit pulsed infrared rays and a light receiver housing a plurality of light receivers that receive each of these infrared rays are installed facing each other across a warning zone, and each transmitter is In the optical beam warning device, the light section and the light receiving section are each coupled by one infrared ray and operate as a pair, and the light transmitter and the light receiver are coupled as a whole by a plurality of warning infrared rays, A number of blocked rays detecting means connected to the plurality of light receivers and configured to detect the number of rays blocked within a minute predetermined time and outputting a separate blocking signal for each number of blocked rays, and the plurality of the number of blocked rays detecting means cutoff time detection means connected to the respective outputs of the plurality of infrared rays, and outputs an alarm signal when the input cutoff signal continues for more than the minimum cutoff time required to issue an alarm, and a predetermined position among the plurality of infrared rays means for detecting that infrared rays have been interrupted for a predetermined period of time and outputting an alarm signal, and the minimum interruption time of each of the interruption time detection means is set to be longer as the number of interruptions is smaller. A light beam warning device featuring: 3. In the light beam alarm device according to claim 1 or 2, a plurality of the above-mentioned cutoff time detection means are provided for each of the plurality of outputs of the above-mentioned cutoff light ray number detection means, so that the same number of light rays are cut off. On the other hand, this light beam alarm device generates different alarms depending on the cut-off time, making it possible to rank the alarms. 4. The light beam alarm device according to claim 1 or 2, wherein each of the cutoff time detection means is capable of variably setting the minimum cutoff time.