JP2875145B2 - Remote control system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote control system for measuring a distance between two separated points by using a distance measuring device mounted on a remote control and a device main body remotely controlled by the remote control.

[0002]

2. Description of the Related Art An apparatus for measuring a distance between two points by using a separated light emitter and light receiver conventionally employs (1) a method in which light and ultrasonic waves are used in combination, resulting from a speed difference between the speed of light and the speed of sound. One that measures the distance between two points by measuring the time difference at the time of arrival, (2)
In some cases, a distance between two points is measured based on an incident angle of light from the light emitter to a position detection type light receiver using a light emitter and a position detection light receiver.

[0003]

However, the device of the above (1) requires a device for generating an ultrasonic wave and a device for receiving a sound wave from the ultrasonic wave, and thus has a problem that the device becomes complicated. . When ultrasonic waves are used, the speed of sound changes depending on the temperature of the measurement environment, and there has been an essential problem that accurate distance measurement cannot be performed.

In the device (2), the light projector is always moved on the optical axis between the predetermined light receiver and the light projector. Therefore, if the light projector deviates from this optical axis, a measurement error occurs. I was

[0005] The present invention has been made in view of such problems, and has as its object to provide a remote control system capable of performing accurate distance measurement.

[0006]

SUMMARY OF THE INVENTION A remote control system according to the present invention includes a projector having first and second light sources which are spaced apart from each other in the width direction of the remote controller and which are alternately lit, and which is incorporated in the remote controller, and which is remotely controlled by the remote controller. And a semiconductor position detector for receiving light from the first and second light sources when the first and second light sources are turned on, and two different positions capable of measuring a distance on the semiconductor position detector A lens for focusing light from the first and second light sources,
A light receiver arranged so that the arrangement direction of the two positions substantially coincides with the width direction of the remote controller; and a calculating means for calculating a distance between the remote controller and the device main body from an output of the semiconductor position detector. And

According to the remote control system of the present invention, the projector has the first and second light sources which are spaced apart from each other in the width direction of the remote controller and are alternately turned on, and the light receiver is a device main body remotely controlled by the remote controller. The lens is installed in a different position sensor that can measure the distance on the semiconductor position detector.
The light from the first and second light sources is focused at two positions, and the arrangement direction of the two positions is arranged so as to substantially coincide with the width direction of the remote control. , The distance between the remote controller and the device main body can be obtained, so that accurate distance measurement can be performed.

[0008] The semiconductor position detector may be a first or second semiconductor position detector.
For each one light pulse incident from the light source, there are provided two electrodes capable of obtaining two signal currents according to the distance between the first and second light sources, the focal length of the lens, and the distance between the light emitter and the light receiver. It is preferable that the arithmetic means differentially amplifies the signal current output in response to the optical pulse giving each of the two positions and obtains the distance in accordance with the amplified output. The output thus obtained hardly changes due to a positional deviation other than the distance between the light emitter and the light receiver, and since the output is differential even if background light exists, this does not cause a large measurement error.

Preferably, the light from the first and second light sources is pulse code modulated. Also, receiving the pulse code modulated light and generating a timing signal,
It is further desirable to hold the output of the semiconductor position detector according to the timing signal. When the light from the first and second light sources is pulse-code modulated, it can be used for various data transmission while eliminating the influence of the background light.

The remote control system according to the present invention further comprises means for adjusting a predetermined function of the device main body in accordance with the distance obtained by the arithmetic means, a remote control receiving unit for receiving a signal from a remote control for controlling the device main body, Preferably, a switch is provided for switching a predetermined function to a function irrelevant to the required distance in accordance with an output signal from the remote control receiver.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a remote control system according to an embodiment will be described with reference to the accompanying drawings. In addition, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.

FIG. 1 is a diagram for explaining a distance measuring device mounted on a remote control system and its measuring principle. As shown in FIG. 1A, the present distance measuring device is a semiconductor position detector 50 (hereinafter, referred to as a light emitter LU) which is disposed opposite to the light emitter LU and receives light from the light emitter LU. And a photodetector RU detected by the PSD 50).

The light projector LU comprises a rectangular parallelepiped driving device 30 and a pair of light-emitting elements (light sources) 10 and 20 such as LEDs arranged on one end surface thereof. Light emitting element 10,
The light emission of 20 is controlled by a driving device 30. The installation interval D between the light emitting elements 10 and 20 is the
The size varies depending on the size of the light receiving unit of the PSD 50, the length of the measurement distance, and the like. For a measurement distance of about 3 m, about 3 to 5 cm is appropriate. Further, it is necessary to change the drive current in accordance with the distance.
200m at peak value in distance measurement of about m
A is appropriate. The drive frequency of the drive device 30 is suitably, for example, around 40 kHz when the light source also serves as a light source for optical data transmission, as described later. This is because it is apparently desirable to blink at approximately 40 kHz.

The light receiver RU includes the light emitting elements 10 and 20 respectively.
It is arranged on the extension of the light emitted from. A lens 40 is fixed to one end surface of the light receiver RU, and focuses light emitted from the light emitting elements 10 and 20 on a light receiving surface of a PSD 50 provided inside the light receiver RU. The PSD 50 and the lens 40 are separated from each other by a focal length f of the lens 40.

Here, the light emission of the light emitting elements 10 and 20 is controlled in accordance with a timing chart as shown in FIG. That is, the light emitting element 10 and the light emitting element 20
Generate light pulse signals by emitting light alternately. Then, this optical pulse signal is introduced into the PSD 50.
The two signal electrodes of the PSD 50 correspond to the distance D between the light emitting elements 10 and 20, the lens focal length f of the PSD 50, and the distance L between the projector LU and the light receiver RU (lens 40) for each light pulse signal of one pulse. A signal is obtained.

That is, the change in the ratio between the signal currents I ₁ and I ₂ obtained from the PSD 50 is evaluated by the arithmetic unit 60 of the PSD 50, so that the light spots from the light emitting elements 10 and 20 focused on the PSD 50 are obtained. Can be calculated by the calculation unit 60. Here, since the distance D and the lens focal length f are known, the distance L between the light emitter LU and the light receiver RU can be obtained according to the principle of triangulation.

That is, if the distance between the position irradiated from the light emitting element 10 and incident on the light receiving element 50 and the position irradiated from the light emitting element 20 and incident on the light receiving element 50 is d,
The distance d between the two light spots is d = f × (D / L) (Equation 1), which is inversely proportional to the distance L between the light receiving unit RU and the light emitting unit LU. And (Equation 1), it is possible to obtain these distances L. For example, f
= 10 mm, D = 50 mm, d = 0.5 mm,
L = 1000 mm is calculated. However, the absolute value of each signal current is the distance (L + f) between the projector LU and the PSD 50.
Emission direction and projector LU, since its size by a driving current changes, the signal current I ₁ to correct the
And after the I ₂ log transformed, it is desirable to take the ratio of the two. FIG. 3C shows each signal current I ₁ and I 2
The relationship between the absolute value of the difference between the _two and the distance L is shown, and FIG. 4D shows the appearance of the projector LU.

Next, the light receiver RU will be described in more detail. FIG. 2 shows an example in which the light receiving unit RU of the distance measuring device shown in FIG. According to such a configuration, the ratio of the signal current obtained by the PSD 50 according to the incident position of the optical signal is calculated by the calculation unit 60. Then, the arithmetic unit 60 outputs a distance signal based on the magnitude of the ratio. The arithmetic unit 60 includes
A second light receiver (for example, a photodiode) 80 and a timing signal generation circuit 70 are connected, and a PSD 50
The sampling of the signal input to the arithmetic unit is performed based on the optical signal received by the second light receiver 80.

FIG. 3 is a diagram showing a more specific configuration of the light receiving unit RU shown in FIG. This light receiver RU operates as follows. First, in the PSD 50, the light emitting element 10
And the signal current resulting from the light emission of 20 is detected. Next, the signal current is converted to the logarithmic amplifier 601 for the aforementioned reason.
The logarithmic conversion is performed at a and 601b to obtain the ratio between the two. The voltage value of this voltage is held by the sample and hold circuits 602a and 602b. The difference between the held voltages is input to the differential amplifier 603, so that the difference between the logarithmic signal voltages, that is, the ratio of the optical signal intensity can be obtained. Note that the output signal from the differential amplifier 603 is rectified by the peak rectifier circuit 604.

These series of operations are alternately repeated with respect to the pulse light from the pair of light emitting elements 10 and 20. Therefore, PS from the output terminal of the differential amplifier 603
An AC voltage having a peak-to-peak value proportional to the distance d between two light spots incident on D50 can be obtained. Therefore, from the distance d, the light emitting unit LU and the light receiving unit RU (PSD50)
(L + f) can be calculated.

Note that the above-mentioned sample hold circuit 602
a and 602b are driven by a timing signal generation circuit 70. That is, the second light receiver 80 is installed near the PSD 50, and detects and amplifies an optical signal alternately emitted from the light emitter LU. Then, the timing signal generation circuit 70 generates a timing signal for performing the sample and hold in the sample and hold circuits 602a and 602b based on the signal from the light receiver 80. With such a configuration, even when the measurement distance is long, the signal-to-noise ratio does not deteriorate, and malfunction due to background light can be reduced.

Incidentally, examples of such a second light receiver 80 include a photodiode, a PIN photodiode, an avalanche photodiode, and the like. From the viewpoint of preventing malfunction, a cut filter for a background light component is provided. A light receiver for optical remote control is desirable.

The sample and hold circuits 602a and 602a
When driving the 02b, a signal obtained from the PSD 50 may be added to an adder (not shown) and taken out. However, the timing is generated by using the second light receiver 80. Compared with the case, the SN ratio is deteriorated in the long distance measurement, and the malfunction due to the background light increases.
In addition, pulse code modulation (PC
If M) is applied, this timing signal can be used for various data transmissions by passing it through the pulse code demodulator 160. Further, the output of the distance signal can be stopped based on the data demodulated by the pulse code demodulator 160. As such a stopping method, for example, a configuration in which the output of the differential amplifier 603 that differentially amplifies the output signal from the PSD 50 is cut off, or the like can be given.

Next, the projector LU and the receiver RU (PSD5)
0) will be described. FIG. 4 is a diagram in which these arrangements are observed from a viewpoint perpendicular to the plane formed by the light emitting elements 10 and 20 and the PSD 50. FIG.
In the case where the PSD 50 is located on the optical axis of the light receiver, FIGS. 8B and 8C show the positional relationship when the PSD 50 is displaced in the plane from the optical axis.

FIG. 5 shows signal waveforms corresponding to (a) to (c). The operation in the logarithmic amplifier is self-evident and will not be described. As is clear from FIG. 5, even if the positions of the light emitting unit LU and the light receiving unit RU deviate from the optical axis, the distance signal (I ₁ −I ₂ ) obtained by differentially amplifying the output of the PSD 50 corresponding to the distance signal. Does not change. Similarly, even if a DC background light exists, the position signal is obtained from the output of the differential amplifier in order to output the distance signal, so that no distance measurement error occurs.

However, in order for the present distance measuring device to operate accurately, the projector LU should be so arranged that the line connecting the light emitting elements 10 and 20 is parallel to the light receiving surface (preferably longitudinal direction) of the PSD 50. Need to be deployed. However, when not arranged in this way, that is, the distance measurement error due to the non-parallel shift is determined by the cosine of the shift angle, so that when the shift is small, this error can be ignored. For example, when adjusting the sound quality between a TV and a stereo sound device or when detecting the distance between a vehicle and a wall of a parking lot, an error caused by the deviation angle is a few percent, and thus is particularly problematic. No.

Next, the magnitude of the light receiving signal will be examined. As a condition, the measured distance is 1 m, and the light emission output is 40 mW / s.
Two LEDs r are arranged alternately at a distance of 5 cm along the width direction of the remote controller and are turned on alternately. The diameter of the lens 40 is 5 mm, and the focal length f is 10 mm. At this time, the input signal light output of the PSD 50 is 0.7.
9 × 10 ⁻⁶ W, P of photoelectric conversion sensitivity 0.5 A / W
Assuming that this is all incident on the light receiving surface of the SD 50, the signal current obtained from the two signal electrodes of the PSD 50 is about 0.4 × 10 ⁻⁶ A in total. At this time, the center distance between the two light spots is 0.5 mm from Equation 1 described with reference to FIG. If the displacement center of the light spot coincides with the center of the PSD 50, if the length of the PSD 50 is 3 mm, the photocurrent generated in each electrode of the PSD 50 is 0.4 × 10, which is a half of the above.
^With respect to ^-6 A, it is alternately increased and decreased by ± 0.25 / 3. In addition, as shown in the conditions (b) and (c) of FIG.
Each signal current corresponding to the amount of movement of the center of displacement of the light spot from the center of 0 is modulated at the above ratio and obtained from each electrode.

As described above, since the distance measurement error due to non-parallel displacement can be ignored when the displacement is small, the distance measurement device is applied to an automatic volume control device and an automatic sound quality control device of a television or a stereo sound device. It is possible to Hereinafter, an audio device using a remote controller equipped with the distance measuring device will be described. First, an example in which the distance measurement device is used for adjusting the volume of an audio device will be described.

When the audio equipment is switched on by the remote control, it is preferable to activate the audio equipment at a low volume so that a large volume is not inadvertently generated. However, since the distance between the viewer and the audio equipment is not fixed, this sound volume cannot always be said to be appropriate. Therefore, if this distance measurement device is applied to audio equipment, the distance can be automatically determined in advance when the audio equipment is turned on. It is possible to start the audio equipment at an appropriate volume. Further, even after the activation of the audio equipment, the volume can be adjusted by determining the distance.

FIG. 6 is a block diagram showing an embodiment of an audio device (device main body) having such an automatic volume control function using such a distance measuring device. In the present embodiment, the sound volume of the television receiver incorporating the audio equipment can be adjusted according to the distance.

The floodlight LU1 with remote control is one in which the floodlight LU shown in FIG. 3 is incorporated in a remote control (attached equipment) for television. 2. Description of the Related Art A remote control for a television receiver is a device that has been conventionally used, for example, that modulates light emission of an infrared light emitting diode, and uses this signal to turn on / off the television receiver, adjust sound quality, and select a station.

First, the distance signal obtained from the photodetector RU shown in FIG.
Input to 0. For example, in this sampling,
The pulse width Tw of the sampling pulse is 50 μs, and the frequency thereof is 1 kHz. Then, the hold signal via the changeover switch 250 (and ON the S _1), is input to the constructed electronic volume 240 from such a variable resistor, for controlling the output of the signal from the signal source 230. That is, in a state where the switch of the television receiver is turned on, the electronic volume is controlled so that the output obtained from the signal source 230 increases as the distance between the viewer with the remote control-equipped projector LU1 and the photodetector RU increases. 240 may be controlled. The signal from the signal source whose output has been adjusted in accordance with the distance signal in this manner is amplified by the amplifier 290 and output from the speaker 300.

Further, since the conventional remote control-equipped projector LU1 is provided with a conventional remote control, a signal from the remote control is detected by a remote control light-receiving section 200 of the remote control which is constituted by using a photodiode or the like. by conducting S ₂ of the switch 250 based on the signal, it is possible to control the electronic volume 280. The electronic volume 280 can also be controlled manually, so that a signal from the remote control is received by the remote control receiving unit 200 and the switch 2 is turned on.
By controlling 50, these functions can be switched.

Further, the power switch 260 of the television can be turned on / off by a signal received by the remote control receiving section 200. The power switch 2 of the TV
The power of 60 is supplied from an AC power supply via a plug 410, and can also be supplied from an auxiliary power supply 270 as shown in FIG. When it is desired to activate the television receiver at an optimum volume, the signal for turning on the power switch 260 from the remote controller of the remote controller LU1 is generated, and at the same time, the projector LU in the remote controller LU1 is turned on. The television receiver can be started at a volume corresponding to the distance to the user. Note that such an automatic volume control function can be applied not only to a simple monaural sound device but also to a stereo sound device and the like.

Next, a description will be given of a television receiver whose sound quality can be adjusted according to the distance. The attenuation of sound power at an audible frequency due to the distance between the viewer and the acoustic device is greater as the frequency is higher. Therefore, when viewing at a long distance, the treble region may sound more natural when emphasized. Also, for a stereo sound source, the sense of realism decreases as the acoustic distance and the distance between the viewer and the viewer increase as compared to the distance between the two sound sources. Therefore, in such a case, the sense of presence is enhanced by attenuating the in-phase component of the stereo sound source and enhancing the anti-phase component.

FIG. 7 is a diagram showing a configuration of a stereophonic apparatus having an automatic sound quality adjusting function to which the distance measuring apparatus is applied. As in the embodiment shown in FIG. 6, the distance signal output from the light receiving unit RU of the distance measuring device is supplied to the sample and hold circuit 220 and the changeover switch 250 (S _1).
Are turned on) to adjust the left and right electronic volumes 314 and 324. That is, for example, assuming that the output of the distance signal increases as the distance between the remote control-equipped projector LU1 and the light receiving unit RU increases, the electronic volumes 314 and 324 are controlled as the distance signal output increases. Amplify the high frequency components of the signals from the signal sources 310 and 320.

The high frequency components are transmitted to the left and right signal sources 310 and 3.
High-frequency components are obtained by applying high-pass filters 312 and 322 to the signal from 20, respectively, and as shown in the drawing, the high-frequency components are amplified by an amplifier. The low frequency components of the signals from the left and right signal sources 310 and 320 are added to the low-pass filter 31 of this signal.
1,321, and these high-frequency components and low-frequency components are cross-over circuits 315,
325. The left and right signal sources 31
The high-frequency components of the signals output from 0 and 320 are adjusted by the electronic volume controls 314 and 324, and then input to the differential amplifier 330 to detect an anti-phase component included in the high-frequency components. Then, the output of the opposite phase component included in the high frequency component is amplified by the variable gain amplifier 331 that operates based on the distance signal output from the light receiver RU.

As described above, in the case of a stereo sound source, realism can be enhanced by enhancing the opposite phase component as compared with the in-phase component. Whether to emphasize the opposite phase component as described above can be selected by controlling the changeover switch 332 based on a signal received by the remote control receiving unit 200. The antiphase component included in the high frequency component is amplified as the distance increases, and the crossover circuit 31
6, 326, a high frequency component and a low frequency component are further combined into a combined signal. Thereafter, the left and right combined signals are sent to speakers 319 and 329 via electronic volumes 317 and 327 and amplifiers 318 and 328, respectively.
Is output from each.

As described above, this acoustic device with an automatic sound quality adjustment function can reproduce natural and realistic sound according to the distance from the stereo sound source. Note that such sound quality control can also be performed by automatically determining the distance when the power of the audio device is turned on, similarly to the audio device with an automatic volume adjustment function. In addition, it is also possible to apply the above-mentioned automatic volume adjustment function and automatic sound quality adjustment function to a single acoustic device.

In the above embodiment, the PSD 50 is used as the semiconductor position detecting device 50. However, as long as it can detect the light receiving position from the light source, a MOS type image sensor or a CCD image sensor can be applied.

As described above, the remote control system has the first and second light sources which are spaced apart from each other along the width direction of the remote control and which are alternately lit, and which is incorporated in the remote control and which is remotely controlled by the remote control. A semiconductor position detector that is incorporated in the device body and receives light from the first and second light sources when the first and second light sources are turned on. A lens for focusing light from the first and second light sources,
A light receiving device arranged so that an arrangement direction of the two positions substantially coincides with a width direction of the remote control; and a calculating means for calculating a distance between the remote control and the device main body from an output of the semiconductor position detector.

According to the present remote control system, the projectors are spaced apart along the width direction of the remote controller and are alternately lit.
And a second light source. The light receiver is incorporated in a device body remotely controlled by a remote controller, and its lens is placed at two different positions on the semiconductor position detector where distance measurement is possible. The light from the light source is focused, and the arrangement direction of the two positions is arranged so as to substantially coincide with the width direction of the remote controller. Can be obtained, so that accurate distance measurement can be performed.

Further, the semiconductor position detector is provided for every one light pulse incident from the first or second light source, the distance between the first and second light sources, the focal length of the lens, and the distance between the light projector and the light receiver. And two arithmetic electrodes are provided for obtaining two signal currents in accordance with the distances, and the arithmetic means differentially amplifies the signal current output in response to the optical pulse giving each of the two positions. It is preferable to obtain the distance in accordance with the output. In this case, the differentially amplified output hardly changes due to the positional shift between the light emitter and the light receiver, and the output is differential even when background light exists. Therefore, this does not become a large measurement error.

It is desirable that the light from the first and second light sources be pulse code modulated. Also, receiving the pulse code modulated light and generating a timing signal,
It is further desirable to hold the output of the semiconductor position detector according to the timing signal. When the light from the first and second light sources is pulse-code modulated, it can be used for various data transmission while eliminating the influence of the background light.

Further, the present remote control system includes a means for adjusting a predetermined function of the equipment main body in accordance with the distance obtained by the arithmetic means, a remote control receiving unit for receiving a signal from a remote control for controlling the equipment main body, Preferably, a switch is provided for switching a predetermined function to a function irrelevant to the required distance in accordance with an output signal from the receiving unit.

[0046]

According to the remote control system of the present invention, the light transmitter and the light receiver are mounted on the remote control and the apparatus main body, and the light transmitter and the light receiver are arranged so that two light spots capable of measuring the distance can be obtained. Since the lights from the two light sources are alternately turned on, accurate distance measurement can be performed.

[Brief description of the drawings]

FIG. 1 is an illustration for explaining a distance measurement device and a measurement principle used in a remote control system.

FIG. 2 is a configuration diagram illustrating a configuration of a distance measurement device.

FIG. 3 is a more specific configuration diagram of the distance measuring device shown in FIG. 2;

FIG. 4 is an explanatory diagram illustrating a principle of distance detection due to a position shift of the distance measurement device.

FIG. 5 is a diagram showing an example of a waveform of a distance signal obtained from the distance measuring device shown in FIG.

FIG. 6 is a configuration diagram of an audio device.

FIG. 7 is a configuration diagram of an audio device.

[Explanation of symbols]

10, 20 ... light emitting element, 30 driving device, 40 ... lens,
Reference numeral 50: semiconductor position detector, 60: calculation unit, 80: second light receiver, 601a, 601b, 220: sample and hold circuit, 603, 330: differential amplifier, 604: peak rectifier circuit, 70: timing signal generation circuit , 80 ... second
, 160 ... Pulse code demodulation circuit, 200 ... Remote control receiver, LU ... Light projector, 230 ... Signal source, 24
0,280,314,324,251,317,327
... Electronic volume, 250,260,332 ... Switch, 270 ... Auxiliary power, 290 ... Amplifier, 30
0, 319, 329: speaker, 410: plug, L
U1 floodlight with remote control, 310 left signal source, 320
Right signal source, 311,321 ... Low-pass filter, 31
2,322 ... High pass fister, 313,323,3
18,328 ... Amplifiers, 315, 325, 316, 32
6. Crossover circuit, 331 Variable gain amplifier.

Claims (5)

(57) [Claims] 1. A projector having first and second light sources which are spaced apart from each other along a width direction of a remote controller and which are alternately lit, and which is incorporated in the remote controller, and which is incorporated in a device main body remotely controlled by the remote controller, When the first and second light sources are turned on, the first
And a lens that focuses light from the first and second light sources at two different positions that can measure distance on the semiconductor position detector and the semiconductor position detector that receives light from the second light source, A light receiver arranged so that the arrangement direction of the two positions substantially coincides with the width direction of the remote control; and a calculating means for calculating a distance between the remote control and the device main body from an output of the semiconductor position detector; A remote control system comprising: 2. The method according to claim 1, wherein the semiconductor position detector includes, for each light pulse incident from the first or second light source, an interval between the first and second light sources, a focal length of the lens, and a distance between the light projector and the light source. The apparatus is provided with two electrodes for obtaining two signal currents according to the distance to the light receiver, and the calculating means subtracts the signal current output corresponding to the light pulse giving each of the two positions. The remote control system according to claim 1, wherein the distance is obtained in accordance with dynamic amplification and the amplified output. 3. The remote control system according to claim 1, wherein light from the first and second light sources is pulse code modulated. 4. The remote control system according to claim 3, wherein the pulse code modulated light is received to generate a timing signal, and the output of the semiconductor position detector is held in accordance with the timing signal. . 5. A means for adjusting a predetermined function of the device main body in accordance with the distance obtained by the arithmetic means, a remote control receiving unit for receiving a signal from the remote control for controlling the device main body, and the remote control receiving unit 2. The remote control system according to claim 1, further comprising: a switch configured to switch the predetermined function to a function irrelevant to the determined distance in accordance with an output signal from the unit.