JP2005249534A - Object detection sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmissive object detection sensor having high resistance to noise light such as disturbance light and accurately detecting an object such as a person or an automobile at a long or middle distance. <P>SOLUTION: This object detection sensor equipped with a determination part 2 for determining the existence of an object 4 depending on whether or not irradiated infrared light L1 is intercepted, comprises a transmission part 3 for irradiating the infrared light L1 as a carrier wave of a prescribed frequency, and a reception part 1 using an infrared remote-control reception element 1A for photoelectrically converting the received infrared light L2 into an electrical signal S1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention uses a light projecting unit that irradiates infrared light and a light receiving unit that receives the infrared light and photoelectrically converts it to obtain an electrical signal. The present invention relates to an object detection sensor that detects the presence or absence of an object.

  As a sensor that includes a light projecting unit and a light receiving unit and detects an object by using a change in an electric signal generated in the light receiving part, a photo interrupter is generally known.

  Photo interrupters are classified into a transmission type and a reflection type. As shown in FIG. 11, the transmissive photo interrupter is configured to detect the presence or absence of an object that blocks the space 11 a by arranging a light receiving element and a light projecting element facing each other in a single housing. ing. As described above, since the presence / absence of an object in the groove portion provided in one housing is detected, it is generally used mainly for short-distance detection, such as position detection of a sliding object or an encoder combined with a slit.

  On the other hand, as shown in FIG. 12, in the reflection type photo interrupter, a light shielding wall is provided between the light receiving element and the light projecting element so that the light from the light projecting element does not directly enter the light receiving element. The reflected light from the object to be detected is received and detected by the light receiving element. This is used for detection from a short distance to a medium to long distance because an object at a position slightly away from the sensor can be detected while arranging the light projecting and receiving elements in the vicinity.

This reflection type is often used for an object detection sensor that detects a certain distance, such as detection of an object conveyed through a conveyance device, and detection of movement of a person or a car.
For example, Patent Document 1 describes an example used for detecting a hand for controlling an automatic faucet device, and Patent Document 2 describes an example used for detecting a person in a toilet.

  In principle, in a sensor using such an optical principle, a transmission type sensor is more advantageous when it is desired to accurately detect the position accuracy of an object. If they are used at the same distance, the light ray trajectory is shorter in the transmission type than in the reflection type, and the optical axis error is also reduced. In addition, since the trajectory is a short distance and the absorption by the sensing object is small, light attenuation is also small.

  Therefore, when it is desired to detect an object at a relatively medium and long distance and with detection accuracy, it is preferable to configure a transmission type object detection sensor. However, the longer detection distance means that the light projecting element and the light receiving element are held in different housings, and the distance between the two becomes longer. Therefore, the probability that the light receiving element receives noisy light such as disturbance light is increased.

  In addition, in order to increase the light projection distance, it is necessary for the light projecting element to narrow the light to be irradiated so that the light does not diffuse, and a high output is also required. Furthermore, considering maintenance, it is required to extend the life by reducing the current flowing through the light projecting element while requiring high output.

JP 2002-48877 PR (FIG. 1, [0001], [0006] paragraphs) Japanese Laid-Open Patent Publication No. 6-142008 (FIG. 2, [0001], [0002], [0007] paragraphs)

  The present invention has been made in view of the above problems, and has an object to provide a transmission type object detection sensor that is highly resistant to noise light such as disturbance light and can accurately detect an object such as a long-distance person or an automobile. It is said.

  The first characteristic configuration of the object detection sensor according to the present invention made in view of the above problems is an object detection sensor including a determination unit that determines the presence or absence of an object based on whether or not irradiated infrared light is blocked. And a transmission unit that irradiates the infrared light as a carrier wave having a predetermined frequency, and a reception unit that uses an infrared remote control reception element that photoelectrically converts the received infrared light to obtain an electrical signal.

  According to the first characteristic configuration, since the receiving unit uses a remote control receiving element having a mass production effect, an object detection sensor can be configured at low cost. In addition, since the receiving circuit using the remote control receiving element includes a band pass filter (hereinafter referred to as BPF) that allows only signals in a predetermined frequency band to pass, resistance to disturbance light is also improved.

  In addition, the transmission unit uses, for example, a carrier wave having a frequency corresponding to the band frequency of the BPF, and for example, causes an infrared LED as a light projecting element to pulse and emit light. Therefore, the power consumption of the infrared LED can be reduced, the life can be extended, and the maintainability of the object detection sensor is improved. Further, the transmission light can transmit a medium and long distance with directivity as in the infrared remote controller. Therefore, it is possible to provide a transmission type object detection sensor that has high resistance to noise light such as disturbance light and can accurately detect an object such as a long-distance person or an automobile.

  In the second characteristic configuration of the object detection sensor according to the present invention, in addition to the first characteristic configuration described above, whether or not the state of the electrical signal is continuously maintained for a predetermined period or longer in the determination unit. By determining whether or not there is an object between the transmitting unit and the receiving unit.

  According to the second feature configuration, the determination unit determines whether or not the signal output from the reception unit is continuously maintained for a predetermined period or longer. The possibility of receiving a transmission signal and causing a false reaction can be significantly reduced.

  The transmission code of the remote control is pulse position modulated (PPM), and the continuous time of the level (High state or Low state) of a signal constituting one code (for example, a code indicating 1 or 0 for 1 bit) is It is about 200 μs. Even if the object to be detected passes through the blocking position, the receiving unit outputs an electrical signal at the blocking position for a time (several tens of ms or more) that is much longer than the continuous time of the level of this signal. To do.

  Accordingly, by confirming that the state of the electric signal is maintained for a predetermined period or longer, it is possible to obtain resistance to noise light caused by the transmission signal of the remote controller. At the same time, it is possible to exclude erroneous reactions caused by disturbance light in a frequency band that passes through the BPF of the receiving unit. As a result, it is possible to provide a transmission type object detection sensor that is highly resistant to noisy light such as disturbance light and other remote control transmission signals, and that can accurately detect objects such as people at long distances and automobiles. Become.

  The third characteristic configuration of the object detection sensor according to the present invention is the above-described second characteristic configuration, in addition to the above-described second characteristic configuration, the determination unit determines whether the state of the electrical signal is continuously maintained. The fixed period includes a first period in which a remote control code signal transmission device that is different from the transmission unit that transmits a remote control code signal that is pulse position modulated in accordance with a carrier wave of the predetermined frequency transmits the remote control code signal, and a remote control Of the second period during which the transmission of the code signal is suspended and the third period representing one code in the remote control code signal, it is longer than the third period and shorter than the second period. It is a set point.

  According to the third characteristic configuration, the time for the determination unit to determine whether or not the signal output from the reception unit is continuously maintained for a predetermined time or more is determined from the form of the transmission signal of the remote control code. Therefore, a more reasonable time setting is possible.

  That is, even when the determination time is long, it is set to be less than the remote control code transmission suspension time, so that erroneous reaction data can be well excluded and an unnecessarily long determination time is not required. Therefore, it is possible to provide a transmission-type object detection sensor that can detect an object such as a long-distance person or an automobile with high accuracy and with high resistance to noise light such as disturbance light quickly and accurately. .

[First embodiment]
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an object detection sensor according to the present invention. Light is emitted from the light projecting unit 3 (transmitting unit), photoelectric conversion and signal processing are performed by the light receiving unit 1 (receiving unit) that has received the irradiation light L1 (transmitting light), and the resulting electric signal S1 is received by the light receiving control unit. 2 (determination unit), the light reception control unit 2 determines the presence and position of the detected object 4, and outputs an object detection signal S2.

  In the present embodiment, the light projecting unit 3 irradiates an infrared light emitting diode (hereinafter referred to as infrared LED) 3a as a light emitting element by turning it on and off by a microcomputer (hereinafter referred to as microcomputer) 3d as a light projecting control unit. Light L1 is projected. The transistor 3e of the LED on / off controller 3b is turned on / off in response to an instruction from the microcomputer 3d via the base current limiting resistor 3f. When the transistor 3e is turned on, the infrared LED 3a is turned on with a current value determined by the resistor 3c as the LED current control unit.

  In this embodiment, the light projection control unit is configured using the microcomputer 3d, but may be configured using a logic circuit. Further, the LED on / off control unit 3b and the LED current control unit 3c may take other forms. For example, an FET is used instead of the transistor 3e, and the LED current control unit 3c is configured by a constant current circuit.

  In this embodiment, the infrared LED 3a is pulsed. In other words, the microcomputer 3d controls the transistor 3e to be turned on and off at regular intervals, thereby turning on and off the infrared LED 3a at regular intervals. Infrared LEDs generally have a long life, but by pulsing them, it is possible to reduce the current flowing per unit time, and they can be used with a longer life.

The irradiation light L1 is irradiated as shown in FIG. The ON / OFF repetition frequency is matched with the light receiving unit 1 described later. In this embodiment, 36.7 kHz, 37.9 kHz, and 40 kHz that are used as a carrier wave for remote control are suitable. FIG. 2 illustrates a 40 kHz carrier wave for ease of explanation. In the following description, the irradiation light L1 that is controlled to repeatedly turn on and off at regular intervals is referred to as “irradiation light L1 output by a carrier wave” or the like.
In this embodiment, the light receiving unit 1 is configured by using a light receiving IC 1A for an infrared remote controller. As already described, the light projecting unit 3 emits the irradiation light L1 output as a carrier wave in accordance with the carrier frequency for the remote controller, so that it can be well received and processed.

The light receiving IC 1A has a photoelectric conversion element such as a PIN photodiode as the light receiving element 1a. The current obtained by photoelectric conversion by the light receiving element 1a is a current-voltage conversion circuit of the light receiving IC 1A,
The signal is output through various signal processing circuits 1b such as an amplifier circuit and a limiter circuit, a band-pass filter (hereinafter referred to as BPF) 1c that extracts a received light signal corresponding to the carrier frequency, a waveform shaping circuit 1d, and an output circuit 1e.

  An example of signal processing is shown in FIG. The light projecting unit 3 irradiates the irradiation light L1 output from the carrier wave, and the incident light L2 is incident as the waveform W1. Waveform W2 is an enlarged view of the carrier wave. A waveform W3 is an example of a waveform after passing through the BPF 1c, and is shaped by the waveform shaping circuit 1d. In the example of FIG. 3, the waveform W3 is integrated to obtain a waveform W4, which is shaped by a comparator having hysteresis thresholds of an upper limit (up) and a lower limit (low). And the output waveform of waveform W5 (electrical signal S1) is obtained via the output circuit 1e.

  In the present embodiment, a configuration in which a light receiving IC for an infrared remote controller is used is shown because it is produced in large quantities for an infrared remote controller and is inexpensive and for the sake of easy explanation. However, the present invention is not limited thereto, and each signal processing as described above may be performed by an individual circuit using a single element such as a PIN photodiode or a phototransistor as a light receiving element.

  When the electrical signal S1 is generated by the light receiving unit 1, the signal is input to the light reception control unit 2. In this embodiment, the light reception control unit 2 is constituted by a microcomputer 2a. Similarly to the light projection control unit 3d, a logic circuit may be used. Further, if arrangement and wiring are permitted, the light emitting control unit 3d may be configured by a common microcomputer or logic circuit.

  The microcomputer 2a of the light reception control unit 2 determines that the incident light L2 is incident on the light reception unit 1 as a predetermined carrier wave during the period Ton when the waveform W5 is in the low state (hereinafter, L state). During the period Toff when the waveform W5 is in a high state (hereinafter, H state), it is determined that the incident light L2 is not incident as a predetermined carrier wave.

  That is, it is determined that the light projecting unit 3 is not projecting light or that the irradiation light L1 is blocked by the detected object 4 that is a blocking object. Then, by knowing the control state of the light projecting unit 3 through a route (not shown), whether or not the light is being projected is added to the determination condition, and whether or not the irradiation light L1 is blocked by the detected object 4 is determined. to decide.

  When the light reception control unit 2 and the light projection control unit 3a are configured by the same microcomputer or logic circuit block, the light projection control information obtained by the light projection control unit 3a that is obtained through the path (not shown) is easily obtained. be able to. FIG. 4 is a flowchart illustrating an example of processing in which the light reception control unit 2 determines the presence or absence of the detected object 4 by looking at the electrical signal S1.

  When the object detection process is started (process # 0), first, an initial (initialization) process of the object detection sensor is performed (process # 1). This is, for example, initialization of various settings inside the microcomputer 2a, initialization of the light receiving IC 1A, and the like. When the initialization process # 1 ends, the object detection signal S2 output from the microcomputer 2a is set to a value (in this example, the L state) when there is no detected object 4 (process # 2).

  Next, it is determined whether or not to continue the object detection measurement (process # 3). If not, the object detection process is terminated. The determination content of the continuation determination includes determination of whether or not the light projecting unit 3 is performing light projection.

  When the object detection process is continued, it is confirmed in the next process whether or not the electrical signal S1 input to the microcomputer 2a is in the H state (process # 4).

  When the electric signal S1 is in the H state, as described above, the light receiving unit 1 does not receive the incident light L2. Since it is confirmed in the process # 3 that the light projecting unit 3 performs the light projecting process, the fact that the light receiving unit 1 does not receive the incident light L2 means that the irradiated light L1 is emitted by the detected object 4. Will be blocked. Accordingly, the light reception control unit 2a determines that the detected object 4 is present, and outputs the object detection signal S2 in the H state where the object is present (process # 8a).

  When the electric signal S1 is in the L state, as described above, the light receiving unit 1 receives the incident light L2. Here, the fact that the light receiving unit 1 receives the incident light L2 means that the irradiation light L1 is not blocked by the detected object 4. Accordingly, the light reception control unit 2a determines that there is no detected object 4, and outputs the object detection signal S2 in the L state in which there is no object (processing # 8b).

  When the process # 8 (process # 8a or # 8b) is finished, the process returns to the process # 3. It is determined whether or not the measurement is continued, and the same processing as described above is repeated. In this way, the presence / absence of an object is continuously detected.

  Although the processing is not shown in the flowchart of FIG. 4, the detected object 4 has entered the detection position at the point where the Ton period and the Toff period transition in the waveform W5 of FIG. It can be determined that the sensor has come out of the detection position. Therefore, not only simple detection of presence / absence, but also use of a plurality of such object detection sensors enables detection of movement and position.

[Second embodiment]
Next, examples in which the above-described embodiment is more suitable will be described.

  In the transmission type object detection sensor configured such that the light receiving unit 1 and the light projecting unit 3 are separated from each other, as described above, the light receiving unit 1 has noisy light that is not the irradiation light L1 from the light projecting unit 3. Is likely to be incident as the incident light L2. There are two types of light that is not the irradiation light L1 that is incident as the incident light L2.

  One is disturbance light such as sunlight and illumination light as already described. In the embodiment described above, an infrared remote-control light-receiving IC is used for the light-receiving unit 1, and the BPF 1c is included therein. Therefore, resistance to disturbance light is ensured. However, disturbance light may include an infrared component. In addition, there may be a frequency component similar to the frequency band of the BPF 1c. As a result, the electric signal S1 may be in the L state.

  The other is a transmission wave from an infrared remote controller that exists separately from the object detection sensor. In an environment in which a person or a car is detected, there is a high possibility that a device that is operated using an infrared remote controller is nearby. Then, the remote control light receiving IC receives and reacts to the transmission signal of the infrared remote controller, and the electric signal S1 may be set to the L state.

  These are shown in the figures as shown in FIGS. FIG. 7 is an example in which the disturbance light L3 is incident on the light receiving unit 1 when the irradiation light L1 from the light projecting unit 3 to the light receiving unit 1 is blocked by the object 4. Due to the disturbance light L3, false detection signals N1 and N2 are output to the electric signal S1 output from the light receiving unit 1. This affects when the wavelength of disturbance light and the frequency of incidence coincide with the wavelength of infrared light and the frequency of a carrier wave.

  FIG. 8 shows an example in which the remote control signal P0 is transmitted from another remote control signal transmission device when the irradiation light L1 from the light projecting unit 3 to the light receiving unit 1 is blocked by the object 4. The remote control signal P0 becomes noisy light L4 and enters the light receiving unit 1, and N1 and N2 false detection signals are output as the electrical signal S1 output from the light receiving unit 1.

  9 and 10, when the irradiation light L1 from the light projecting unit 3 to the light receiving unit 1 is incident on the light receiving unit 1 without being blocked, the remote control signal P0 is transmitted from another remote control signal transmitting device. This is an example. The remote control signal P0 becomes noisy light L4 and enters the light receiving unit 1, and N1 and N2 false detection signals are output as the electrical signal S1 output from the light receiving unit 1. In this case, the incident light L2 has been received and a low output has already been output, but the waveform of the incident light L2 as a carrier wave regularly received is disturbed as shown in FIG. Occur. Thus, the output electric signal S1 changes under the influence of the remote control transmission signal P0.

  Therefore, an embodiment of an object detection sensor in which resistance to noise light is further improved by being configured not to be affected even when such disturbance light or a transmission signal from another remote controller is received will be described below.

  Transmission by the infrared remote controller is normally performed as shown in FIG. That is, using the carrier wave P2, the code signal to be transmitted is subjected to pulse position modulation like the waveform P2. The pulse position modulated code signal includes codes such as a start bit, a stop bit, 0, 1 and the like, and each code is shown in a period T3 having a different length. A period T1 for transmitting one frame of the pulse position-modulated code as a code signal and a period T2 for pausing are provided for transmission.

  FIG. 6 shows an example in which a code signal of one frame is transmitted including a code signal of 0110 between a start bit (leader) and a stop bit (trailer).

  In the example shown in FIG. 6, the carrier wave is shown as 40 kHz which is the same as the irradiation light L1 of the present embodiment. A period T3 representing one code, where one period of the carrier wave is T, is configured such that the code 0 is twice T and the code 1 is four times T. The code transmission period T1 is about 20 ms, and the code transmission suspension period T2 is about 40 ms.

  Even if a transmission wave from another infrared remote control code transmitter is received using the period T3 indicating one code, the code transmission period T1, and the code transmission period T2, the detection performance is not affected. It is possible to constitute a simple object detection sensor.

  By adding the following processing to the processing flow of the determination unit 2 shown in FIG. 4, a more suitable object detection sensor can be obtained. This processing flow is shown in FIG.

  The process up to process # 4 is the same as the process flow shown in FIG. When the signal level of the electrical signal S1 output from the receiving unit 1 is confirmed, the timer in the control unit 2 (in this example, inside the microcomputer 2a, both not shown) is reset (# 5).

  When the electrical signal S1 output from the receiver 1 is in the H state, that is, when there is a high possibility that the detected object 4 is blocking the irradiation light L1, the electrical signal S1 is again in the H state. It is confirmed whether or not there is (process # 6a). If the electric signal S1 is not already in the H state, the process returns to the process # 3. That is, assuming that the H level confirmed in the process # 4 is ambient light or a transmission wave of another remote controller, the measurement is continued by returning to the process # 3 without setting the object detection signal S2 to the H state.

  If the electric signal S1 is in the H state in the process # 6a, the timer value is checked next (process # 7). Here, if the value of the timer is equal to or greater than a predetermined value (Tref) set in advance, it means that the electric signal S1 has maintained the H state for a predetermined time or more. In this embodiment, the predetermined time to be maintained is set to, for example, 36 ms, which is slightly shorter than the code transmission pause period T2. If the timer value has not reached the predetermined time of 36 ms, the process returns to the process # 6a to confirm the state of the electric signal S1 again.

  Thus, by repeating the processing 6a and the processing 7, it is confirmed whether or not the state of the electric signal S1 is maintained for a predetermined time. If it is confirmed that the state of the electric signal S1 has changed during the repetition, the process returns to the process # 3. Note that when the process # 6a and the process # 7 are repeated, a wait (#W) may be added to the program according to the processing speed of the control unit 2.

  In process # 7, when it is confirmed that the electrical signal S1 is maintained for a predetermined time or longer, the object detection signal S2 is output (process # 8a). And it returns to process # 3 and continues observation.

  In the process # 4, the process when the electric signal S1 is in the L state is the same.

  By configuring the determination unit 2 in this way, it is possible to realize an accurate object detection sensor by eliminating an erroneous reaction of the light receiving unit 1 due to disturbance light or a transmission wave of another remote controller.

  In the present embodiment, an example is shown in which the predetermined time during which the electric signal S1 should be maintained is, for example, 36 ms, which is slightly shorter than the code transmission pause period T2. This is because, if it coincides with the whole period of the code transmission pause time T2, there is a high possibility that it will collide with the preceding and following code transmission periods T1, and there is a possibility that correct detection results will be excluded.

  In the case of setting a short time, for example, it is possible to shorten the time to about T3 representing one code. However, this is effective when only the transmission wave of another remote controller is considered, but it can be said that it is too short considering the exclusion of the influence of disturbance light or the like.

  Therefore, in this embodiment, about 90% of the time period T2 is set as a time slightly shorter than the code transmission suspension period T2.

  The code of the remote controller has a wide allowable range assigned to each manufacturer, and the code transmission period T1 may vary depending on the amount of code to be transmitted. Further, the code transmission suspension period T2 may also vary accordingly. Therefore, it is also useful to be able to vary the time during which the electric signal S1 should be maintained according to the environment in which the object detection sensor is installed.

  Conversely, it is also possible to construct an object detection sensor at a low cost by fixing the time considered to be the shortest. In that case, what is necessary is just to define the time which the electric signal S1 should be maintained from the following viewpoints.

  In the remote control code format established by the Home Appliances Association, the unmodulated period T4 of the stop bit (also referred to as trailer) may be 8 ms or more, and at least the period T2 corresponding to the data transmission suspension period is 8 ms. It will be a longer period. Therefore, 8 ms is used as a reference. Further, it may be obtained experimentally by using several types of infrared remote control signal transmitters. An actual measurement value of a remote controller used in a game machine or the like is about 10 ms, and this area may be set as the shortest time.

  As described above, with the configuration described above, it is possible to provide an object detection sensor that eliminates the influence of noisy light such as disturbance light and another infrared remote control transmission wave.

  The irradiation light L1 is configured to output a carrier wave stably over a period of time longer than the time for maintaining the state of the electric signal S1. Since the time for maintaining the state of the electric signal S1 output by the receiving unit 1 is determined, the irradiation light L1 is irradiated so that the state of the electric signal S1 can be maintained if there is no influence of noisy light.

  More preferably, if the irradiation light L1 is continuous, the change of the electrical signal S1 during the non-output of the carrier wave can be captured in real time, so that the carrier wave may be always output. Note that the constant output includes repeating output and non-output for a certain period.

  Further, in FIG. 2, FIG. 3, etc., the waveform of the carrier wave of the irradiation light L1 is exemplified by the 50% duty pulse waveform. However, the present invention is not limited to this, and can be lowered to about 20% to 25%. By reducing the duty, it is possible to suppress power consumption without affecting the frequency of the carrier wave.

  By configuring as described above, it is possible to provide a transmission type object detection sensor that is highly resistant to noisy light such as disturbance light and can accurately detect an object such as a long-distance person or an automobile. It becomes possible.

Schematic showing a block configuration example of an object detection sensor according to the present invention Waveform diagram showing an example of irradiation light from the light projecting unit of FIG. Waveform diagram showing an example of signal processing of the light receiving IC of FIG. FIG. 1 is a schematic flowchart showing processing of the determination unit in FIG. FIG. 1 is a schematic flowchart showing processing of the determination unit in FIG. Waveform diagram showing an example of remote control code transmission The figure which shows the example in case the object detection sensor which concerns on this invention receives noisy light The figure which shows the example in case the object detection sensor which concerns on this invention receives noisy light The figure which shows the example in case the object detection sensor which concerns on this invention receives noisy light Waveform diagram showing an example where the remote control transmission wave becomes noisy light Conceptual diagram showing the configuration of a general transmissive photo interrupter Schematic diagram showing the configuration of a typical reflective photointerrupter

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reception part 1A Infrared remote control receiving element 2 Judgment part 3 Transmission part 4 Object S1 Electrical signal

Claims (3)

An object detection sensor including a determination unit that determines the presence or absence of an object depending on whether or not irradiated infrared light is blocked,
A transmitter that irradiates the infrared light as a carrier wave of a predetermined frequency;
A receiving unit using an infrared remote control receiving element that photoelectrically converts the received infrared light to obtain an electrical signal;
An object detection sensor.  In the determination unit, the presence or absence of an object between the transmission unit and the reception unit is detected by determining whether or not the state of the electrical signal is continuously maintained for a predetermined period or longer. The object detection sensor according to claim 1. In the determination unit, the predetermined period for determining whether or not the state of the electric signal is continuously maintained,
A remote control code signal transmitting device that transmits a remote control code signal that is pulse position modulated in accordance with a carrier wave of the predetermined frequency, and a remote control code signal transmission device that is different from the transmission unit transmits the remote control code signal; Of a second period for suspending transmission and a third period representing one code in the remote control code signal,
The object detection sensor according to claim 2, wherein the object detection sensor is set longer than the third period and shorter than the second period.

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