FR2987157A1 - Home automation apparatus for use in warning system, has electronic control circuit controlling lighting of display on reception of object presence signal, where circuit is insensitive with presence of object apart from detection zone - Google Patents

Abstract

The apparatus has a man-machine interface comprising a luminous display (11) i.e. LCD touch screen, a remote sensing device (15), and an electronic control circuit (13) for controlling the display according to a predetermined criteria. The display receives a signal that is delivered by the remote sensing device. The electronic control circuit is utilized for controlling lighting of the display on reception of an object presence signal (14) delivered by the remote sensing device. The control circuit is insensitive with the presence of an object i.e. hand (26), apart from a detection zone (16).

Description

The invention relates to a home automation system apparatus, in particular an alarm system, comprising a man / machine interface comprising a light display and an electronic circuit. control of the display adapted to control the extinction of the display according to predetermined criteria, and the lighting of the display on receipt of a signal delivered by a remote detection device.

US 7394451 discloses an interface apparatus with a control system such as a home automation system comprising an LCD touch screen and a motion detector used to turn on the backlight of the screen as a person approaches the apparatus. The motion detector is a pyroelectric infrared detector (PISO 1E in Fig. 10B of this document). Such a motion detector, which is a passive detector, necessarily detects non-selectively any presence of movement in its field, which extends over several meters, typically between 3 m and 10 m and over an angular sector greater than 120 °. . As a result, the screen is turned on and off improperly every time a person goes into the field of view of the detector. In the case of a home automation system without alarm features, this fault results in unnecessary power consumption and premature wear of the display and associated electronics. It can be difficult for users. In the case of a home automation system with alarm features, this defect is unacceptable, since it allows anyone, including possibly malicious, to detect the presence of the long-distance screen and access information. displayed, or even to use the corresponding touch keys. Furthermore, reactivating a touch screen by a first contact on this screen is also not appropriate in the case of a home automation system device, more particularly in the case of a device such as a central unit alarm system. Indeed, there is then a significant risk that this first contact generates the inadvertent activation of a function corresponding to an active key of the screen. In addition, the need for such a first prior contact represents an inconvenience and a lack of ergonomics. In this context, the inventors have determined that it would be particularly advantageous to allow, on the one hand, a systematic and almost permanent extinction of the display, and an automatic reactivation of the latter only following the action of an authorized user other than a user. direct contact on the display or the device. The invention therefore aims to propose a home automation system apparatus, and more particularly an alarm system central unit, having a normally off display (in particular not visible, or in any case undetectable, from a certain distance) and can be reactivated automatically only after a gesture by an authorized user other than a direct contact on the display or the device. The invention aims in particular to provide such an apparatus in which the reactivation of the display is performed reliably, without being disturbed by variations in the environment (passage of people in the vicinity of the device, variations of lighting, passage of external sources of heat, parasitic reflections on fixed elements ...). The invention also aims to provide such a device whose use is particularly pleasant and ergonomic, simple, intuitive. It is more particularly intended to provide such a device which is moreover energy efficient, and which in particular can operate on an autonomous power source (batteries, batteries, etc.) over a long period of time. The invention also aims to provide a home automation system 25 including an alarm system- having the same advantages, including including at least one device such as a central control unit having these advantages. For this purpose, the invention relates to a home automation system apparatus, in particular an alarm system, comprising a man / machine interface comprising a light display, a remote detection device and an electronic display control circuit capable of controlling the display. controlling the extinction of the display according to predetermined criteria, and switching on the display upon reception of a signal delivered by said remote detection device, characterized in that said remote detection device is adapted to: - selectively detect the presence of an object only in a zone of space, called the detection zone, extending over a non-zero detection distance of less than 1 m, in particular between 10 cm and 50 cm -1 of said display, and to deliver a signal, said presence signal, representative of the selective detection of such a presence, and in that said electronic control circuit is adapted po to control the lighting of said display on receipt of a presence signal delivered by the remote detection device, - to be insensitive to the presence of an object outside the detection zone, that is to say situated beyond the detection distance. The remote sensing device is "insensitive" in that the signal that it delivers or not is not changed by the presence or absence of an object outside the detection zone. The inventors have indeed found that on the one hand to provide a selective detection device (including an active detection device by reflection and not a passive motion detection device in general), and on the other hand, limiting the detection zone to such a non-zero but low detection distance provides in practice a very large number of advantages, in particular prevents unnecessary activation of the display while allowing this activation reliably and safely when it is necessary and useful for an authorized user. In addition, such a selective detection device proves to be particularly simple and inexpensive, in particular is actually simpler and more economical than a presence detector such as a passive infrared sensor. In an apparatus according to the invention, the remote sensing device may be selected from any of the sensing devices which are suitable or which may be adapted to exhibit the above characteristics. Advantageously and according to the invention, the remote detection device comprises at least one transmitter (s) / receiver (s) of radiation, and is adapted to emit a presence signal upon reception by said set, of a corresponding flow. selectively to a flux emitted by said assembly and reflected by an object located in said detection zone. In other words, the remote detection device is a radiation reflection detection device by the object (hand of the user approaching the display) to be detected. Thus, it suffices to choose the characteristics of the emitted radiation, for example in terms of wavelength, to ensure that the detection by the remote detection device is strictly selective, the detection of the reception of this stream not being in danger. be disturbed by external events. In a particularly advantageous embodiment and according to the invention, the remote detection device comprises at least one transmitter (s) / receiver (s) comprising at least one electromagnetic radiation emitter of predetermined specific characteristics -particularly to a length predetermined central waveband and bandwidth of less than 100 nm; and at least one receiver capable of selectively detecting the reception of electromagnetic radiation corresponding to said predetermined specific characteristics. Such a remote sensing device is of the active type, which allows to give it a high accuracy, high reliability and high reliability. An apparatus according to the invention may comprise one (or more) set (s) transmitter (s) / receiver (s), each set transmitter (s) / receiver (s) comprising at least one transmitter and at least one associated receiver and which can be chosen from among all the technologies enabling such active reflection detection, and in particular the technologies using light radiation (preferably in the infrared range, but also possibly in the visible range) and / or radiation in the microwave domain (radar or microwaves). The same transmitter / receiver unit (s) can also combine several radiations of different characteristics, for example a radiation (and therefore at least one transmitter and at least one receiver) in the infrared range and a radiation (and therefore at least one transmitter and at least one receiver) in the visible range. The receivers that can be used with the light rays can be for example chosen from unitary photodetectors or matrices (photodiodes, phototransistors, CCD sensors, APS sensors, etc.). In particular, advantageously and according to the invention, at least one transmitter / receiver unit (s) comprises at least one infrared radiation emitter (for example an infrared LED) and at least one receiver (for example a photodiode or a photodiode). an infrared phototransistor) capable of detecting this infrared radiation. More particularly, advantageously and according to the invention, the remote detection device comprises at least one transmitter (s) / receiver (s) comprising at least one infrared electromagnetic radiation emitter of central wavelength between 0, 76 gm and 1 μm and bandwidth less than 100 nm. Such specific infrared radiation makes it possible in particular to overcome any interference with other ambient radiation. Also, advantageously and according to the invention, the remote detection device comprises at least one transmitter (s) / receiver (s) comprising at least one transmitter adapted to emit radiation pulses each having a duration less than 20 1. is - in particular of the order of 20 or less than 10 μs -. In addition, advantageously and according to the invention, the remote detection device comprises at least one transmitter (s) / receiver (s) comprising at least one transmitter adapted to emit separate radiation pulses with a duration of less than 1s. especially of the order of or less than 0.1s. Here again, these values make it possible in practice to avoid any parasitic interference, and to optimize the energy consumption of the apparatus, particularly when it is on standby. In particular, at least one transmitter / receiver unit (s) operates at a frequency that is greater than the frequencies of most household appliances such as computer or television displays, lighting fixtures (neon, bulbs with 30 discharges ...) that can be located nearby. However, other values are possible.

The invention applies particularly advantageously to a device whose display is a touch screen adapted to emulate keys that can be activated by a user. Thus, on detection of the presence signal, triggered by the presence (necessarily voluntary) of the user's hand in the immediate vicinity of the display, the display is illuminated, so that the keys emulated by the display become visible. In an advantageous embodiment and according to the invention, said display is a backlit display. Said electronic control circuit is then advantageously adapted to control the backlighting of the display only when said remote detection device selectively detects the presence of at least a portion of a human hand in said detection zone. The invention nevertheless also applies to the case of a touch screen and any form of illuminated display. Furthermore, advantageously an apparatus according to the invention is also characterized in that it is in the form of a housing having said display on one of its faces whose appearance merges with that of the display, so that it is adapted so that said display is, when turned off, not detectable at least at a viewing distance greater than said detection distance especially greater than lm-. Thus, from a certain viewing distance, a person passing near the device does not detect the presence of the display and, except to be a user previously informed of the presence of the display, does not seek so not even to activate it. On the other hand, as soon as an informed user passes his hand near the apparatus, in said detection zone, the illumination of the display is activated and in particular the information displayed by the display is visible. In the case of a backlit touch screen, the active keys emulated by the display are usable. In a particularly advantageous embodiment and according to the invention, said remote detection device is adapted to allow adjustment of the extension of said detection zone, that is to say of said detection distance. This adjustment can for example be obtained by the actuation of active keys emulated by the display itself, which makes it possible in particular, for example, to vary the intensity of the supply current of the transmitter of the transmitter unit. (s) / receptor (s). The invention applies in particular to a home automation system, that is to say a system for centralizing the control and / or monitoring of various devices related to a residential or professional building (heating, lighting, air conditioning, shutters, windows, doors, gates, electrical outlets, security (alarms, intercoms ...), operation monitoring, household appliances, computer and / or video and / or audio devices, assistive devices and life support robots The invention therefore extends to a home automation system comprising at least one apparatus according to the invention. In particular, the invention applies to a home automation system-in particular adapted to act as an alarm system-which comprises at least one central unit formed of an apparatus according to the invention.

The invention also relates to an apparatus and a home automation system characterized in combination by all or some of the characteristics mentioned above or below. Other objects, features and advantages of the invention will become apparent on reading the following description given by way of non-limiting example of embodiment of the invention and which refers to the appended figures in which: FIGS. 1b are schematic perspective views of an apparatus according to an embodiment of the invention shown respectively with the illumination of the display off and with the illumination of the display on, FIG. 2 is a diagram. functional block diagram illustrating the operating principle and the main components of an apparatus according to one embodiment of the invention, - Figure 3 is a diagram illustrating the geometry of the detection principle in an apparatus according to the invention, 2 9 8 FIG. 4 is a timing diagram illustrating the operating principle of transmission and reception detection in an apparatus according to the invention, FIG. 5 is a graph illustrating FIG. examples of variations of the current delivered by a photodiode serving as a receiver as a function of the distance of a target object from the detection device in an apparatus according to the invention; - FIG. 6 is a diagram of an exemplary embodiment of an electronic control circuit of an LED emitting a device for detecting a device according to the invention, - Figure 7 is a diagram of an exemplary embodiment of an electronic signal processing circuit. delivered by a photodiode serving as a receiver of a device for detecting an apparatus according to the invention. An apparatus according to the invention is for example a central unit of home automation system. It comprises a housing 10 and a man / machine interface comprising a luminous display 11 having a lighting 12 which can be switched off or on by a control electronic circuit 13 depending on the state of a signal, said detection signal 14, delivered by a remote sensing device 15. When the illumination 12 of the illuminated display 11 is lit, the display 11 is visible from the outside, that is to say that the information it presents, including any active buttons 29 emulated it is a touch screen, are visible. On the contrary, when the illumination 12 of the illuminated display 11 is off, the information normally presented by this display 11 (including any keys 29 emulated by this display 11) are not visible. Preferably, the display 11 itself is not detectable, and coincides with the rest of the outer wall of the housing 10 of the apparatus as shown in Figure 1a. The remote sensing device 15 is a device adapted to selectively detect the presence of an object 26 - in particular at least a part of a human hand 26 - located only in a zone of space, called zone 16 of detection, extending over a distance d that is not zero but limited from the display 11. This remote detection device 15 comprises at least one transmitter / receiver unit (s). an electromagnetic radiation, called electromagnetic detection radiation, and this assembly is adapted to emit a presence signal upon reception (by this set) of an electromagnetic flux corresponding selectively to the electromagnetic detection radiation emitted by said assembly and reflected by an object located in said detection zone 16. Since the electromagnetic radiation of detection emitted by such an assembly is specific and each receiver selectively analyzes the received electromagnetic flux corresponding to this radiation, it is freed from any parasitic fluxes, and the range of the detection zone can be determined, even adjusted, with precision. The specificity of the electromagnetic radiation of detection emitted and received by the detection device 15 can be obtained in various ways, in particular by the choice of a specific central wavelength and / or a bandwidth of lengths. specific wave and / or a specific waveform of the radiation -especially in the form of pulses of specific duration and / or separated from each other by a specific duration-. In a preferred embodiment, said detection electromagnetic radiation is a radiation emitting outside the visible range, more particularly an infrared radiation, preferably having a central wavelength of between 0.76 μm and 1 μm and a width of band below 100 nm. It should be noted in particular that this range of wavelengths makes it possible to avoid the detection of infrared radiation emitted by people or animals as detected by passive infrared pyroelectric detectors. Such an infrared detection electromagnetic radiation may be emitted by at least one infrared LED 17, for example of the SFH4056 type (see www.osram-os.com). Each infrared LED 17 which thus acts as a transmitter of the electromagnetic detection radiation is fixed on the housing 10 of the apparatus so as to emit a diverging infrared flux 18 from the display 11 and in at least a substantially normal direction to the latter. In addition, each transmitter 17 is also adapted so that a space zone extending from the display 11 and out of the display 11 over a distance is scanned by at least one stream 18 emitted by such an emitter 17. Several alternative embodiments are possible with regard to the choice and use of the emitted detection radiation flux. In a first variant according to the invention, each emitter 17 is chosen, arranged and adapted so that the emitted detection radiation forms a detection surface at a predetermined distance from the display 11, the detection surface necessarily cut off by the hand a user who approaches the display 11 to activate it by entering the detection zone 16 containing this detection surface. In another variant according to the invention, each emitter 17 is chosen, arranged is adapted so that the electromagnetic detection radiation scans any point of the detection zone 16 which extends outside the display 11, at less than a predetermined distance. In particular, the radiation flux emitted by each transmitter 17 is of type 15 diverging from this transmitter 17 so as to cover a portion of space as large as possible. Advantageously, each emitter 17 is chosen so as to emit a generally conical radiation with a half-angle at the vertex greater than 10 °, for example of the order of 20 ° to 30 °. An apparatus according to the invention may, in certain embodiments, comprise a single emitter 17, for example placed substantially in the central position of the display 11, with a sufficient emitted flux and adapted to allow detection of the hand of a user approaching the display 11. In other embodiments of the invention, the apparatus comprises a plurality of emitters 17 in particular to better cover the detection zone 16. In the preferred embodiment shown in FIGS. 1a, 1b and 2, the apparatus according to the invention comprises two remote infrared emitting LEDs 17, and a receiver in the form of a receiving photodiode 19 interposed at least substantially at mid-range. distance between these two transmitters 17. The use of several transmitters 17, in particular at least two transmitters 17, 30 provides a good coverage and a sufficiently large detection area 16. It also makes it possible to determine the nature of the displacement - in particular the direction of movement - of the object in the detection zone 16 as soon as the fluxes emitted by the different emitters 17 have specific characteristics that are distinct from one another. For example, the pulses emitted by the different LEDs 17 may be out of phase with each other. The fact of being able to determine the nature of the displacement of the object, in particular its direction of movement relative to the display, makes it possible to configure specific commands that can be imparted by the user to the display according to this nature of the displacement. . For example, when the user moves his hand in one direction, the signal processing circuit 21 can interpret this type of movement as an activation command for certain keys 29 emulated by the display, for example the keys for controlling home automation devices, and when the user moves his hand in the other direction, the signal processing circuit 21 can interpret this type of displacement as a command to turn off the display or as an activation command of other keys, for example only keys for controlling alarm devices. Of course, many variants of embodiment and application of this principle can be envisaged in an apparatus according to the invention, for example with a sufficient number of transmitters to be able to detect a rotation of the hand in one direction or in the other ... Also, an apparatus according to the invention may comprise a single receiver or on the contrary a plurality of receivers adapted to receive a flow of electromagnetic radiation detection reflected by an object located in the detection zone 16. Each receiver 19 may be a broadband receiver adapted to receive non-specifically the electromagnetic radiation detection (that is to say to receive electromagnetic radiation of general characteristics nonspecific, but including those of the electromagnetic radiation detection), the detection selective reception of a flow of electromagnetic radiation detection being performed by an electronic signal processing circuit delivered by such a broadband receiver. Alternatively or in combination, each receiver 19 may be a specifically selected receiver, arranged and adapted to receive electromagnetic radiation of which at least some characteristics correspond exclusively to those of the electromagnetic radiation detection. Preferably, each receiver 19 is selected to selectively detect central wavelength and wavelength bandwidth radiation as closely as possible to the center wavelength and the bandwidth. In addition, each receiver 19 is also selected with respect to its detection angle and its dynamic detection characteristics to be compatible with the geometric and temporal characteristics of the radiation. of reflected detection, particularly with regard to the individual duration of each pulse of radiation and the repetition frequency of these pulses. Advantageously, each receiver 19 is chosen so as to have a detection field which is at least substantially conical with a half-angle at the apex greater than 20 °, for example of the order of 45 ° to 70 °. In the example shown in the figures, the apparatus comprises a single receiver 19 in the form of an infrared photodiode, for example of the BPW34FAS type (see www.osram-os.com), interposed between the two transmitters 17. transmitter (s) / receiver (s) formed by the two emitters 17 and the receiver 19 also comprises a signal processing circuit 21 delivered by the receiver 19, allowing the selective detection of the presence of an object located in the detection zone 16. This signal processing circuit 21 comprises a current / voltage converter 22 delivering a voltage corresponding to the current delivered by the photodiode 19, a filtering circuit 23, and an analog / digital converter 24 delivering a signal for a microcontroller 25. microcontroller 25 is adapted to be able to analyze this signal, compare it in particular with an amplitude threshold AV1 of voltage, synchronously with the emission of the pulses by the emitters 17, and determine if this signal corresponds to a flux reflected by a object located in the detection zone 16. If so, the microcontroller 25 emits a detection signal 14 which triggers the illumination of the illumination 12.

The microcontroller 25 is also connected to the LEDs 17 emitting so as to control the emission of the pulses according to predetermined characteristics specific to the electromagnetic radiation detection. With such a detection device, detection of the received detection electromagnetic radiation is effected synchronously with the emission of this radiation. The detection zone 16 in which the presence of an object is selectively detected by the detection device extends from the display 11 to the outside of the latter over a limited non-zero detection distance d relatively weak, less than 1 m, in particular between 10 cm and 50 cm -1. This detection distance d may also be referred to as detection range by the remote sensing device. FIG. 3 is a geometric diagram that makes it possible to determine this range. The remote sensing device 15 is insensitive to the presence or absence of an object in an area of space extending beyond the sensing distance d, i.e. the signal 14 possibly delivered by this remote detection device 15, and more generally the state of the receiver 19 and that in particular of the output of this receiver 19 and the output of the signal processing circuit 21 delivering this signal 14, remain unchanged according to whether an object 26 is present or not beyond the detection zone 16. By considering a surface target object Sc which collects at the distance R1 from the emitting LED a flux F1 expressed in Watts which is proportional to the product of the emitter / target misalignment with the solid angle S21 and the energy intensity W / sr emitted by the LED 17 for example SFH4056 type (driven in pulsed mode to ensure minimum Il = 50m W / sr): c F1 = IE01 cos = IE n cos S2 S per unit area of Sc the target object, a perceived illumination E1 (Wm-2) of the LED 17, defined according to the law of Move: IE = Fi = - cos ai S, Ri2 Assuming that the target object behaves like a radiation diffuser orthotropic (approximation of a Lambertian source), a part of this received illumination Ei will be reflected by the target object in the form of a luminescence L1 expressed in Wm-2sr-1 where p is the reflection coefficient. The expression of the luminescence LI is written as: L1 = El-p = -p cos ai with p <1 Rl 71 "The target object 26 then behaves as an energy intensity emitting source /, (W. sil) whose equation is: 12 = LIS, cos a, 10 Let us now consider the photoreceptor 19, for example of type BPW34FAS with area Sp = 7mm2, which collects at the distance R2 from the target object 26 a received illumination E2 ( Wm-2), defined according to the Bouger law: E2 = I2 cos a = = 2 2 R2 cos2 a 2 RI p cos ai cos 2 a, R2 2 2 1 2 As E2, we deduce the expression F2 flux expressed in If 15 Watts: F is F2 = I1Q1 2 cos cos, SC cos 2 cos 2 COS 2 = - R2R 2 1 1 2 With a sensitivity of 0.65A / W, the value of Ip intensity of the current delivered by the photoreceptor 19. FIG. 5 is a graph illustrating the variations of this intensity as a function of the distance X between the object 26 and the detection device (i.e. of the transmitter 17 and the receiver 19, or, in the embodiment shown, the plane of the display 11), for two surface values of the target object, namely respectively 5 cm 2 and 120 cm 2. Two modes of operation of this principle of reflection detection are to be considered: - first mode of operation: the target object 26 is located at a distance such that the cosine of the angles al and a2 must be taken into account: it is therefore located in an area very close to the detection device and the display, typically from 1 cm to 3 cm, - second mode of operation: the target object 26 is located at a distance such that cosai = cosa2 1, a condition obtained when this object 26 moves away from the detection device, the expression of the intensity of the current emitted by the receiver photo 19 is written as a function of the distance X between the target object 26 and the detection device as follows This shows that the detection device 15 has an attenuation varying according to the power 4 of the distance X between target object 26 and the detection device. This attenuation can be modeled according to a function G defined by: Ip = G (X-4) In other words, the proximity detection capability of the detection device 15 is governed by an X "law, corresponding to an equal steering coefficient The determination of the detection distance d, i.e., the extension distance of the detection zone 16, depends on the capacity of the signal processing circuit 21 to be at a logarithmic pattern. extracting the useful signal from the noise in the current delivered by the receiver 19. The effective value of the noise of a photodiode 19 used as receiver can, in the first order, be assimilated to I ,, = + 4 = V2qID4f + 4kBTAf / R = 60pA q being the elementary charge of the electron: 1.6 10-19C ID being the dark current (for example 2nA for the circuit BPW34FAS) M being the bandwidth of the assembly (for example Af = 100kHz) kB being the Boltzmann constant = 1.38 10-23 J / KR being the resistance e equivalent shunt of the photodiode (5001 (0). By considering, 4,> 1001 'it is deduced that the minimum value of the current that can be detected is // ,,,, in = 6nA, ie, in view of FIG. 5, a detection distance d varying between 25 cm and 50 cm. according to the surface of the target object 26. It is therefore possible, with such a device, to adjust the intensity emitted by the LED 17, in particular by adjusting the intensity of its feed current, so that the reflected flux picked up by the receiver 19 sufficiently large in case of presence of an object 26 in the detection zone 16, but, on the other hand, to obtain an appropriate attenuation allowing a discrimination of the presence or not of the target object in the zone 16 of detection only over a predetermined detection distance d which may be less than 1 m, typically 10 cm and 50 cm, taking into account the attenuation mentioned above and the detection threshold of the signal processing circuit 21. The detection zone 16 thus extends along a hemisphere whose radius corresponds to the above-mentioned detection distance d, and which is centered on the receiver 19. FIGS. 6 and 7 give non-limiting examples of simplified electronic diagrams, understandable in themselves, can be used for the control of each LED 17 transmitter and, respectively, for the processing of the signal delivered by the photodiode 19 receiver. In these diagrams, D 1 is a transmitter LED 17, D5 is a receiver photodiode 19, and, according to the usual nomenclature, the components referenced Di are diodes, Ri are resistors, Ci are capacitors, Qi are bipolar transistors. . The intensity of the current flowing through the LED 17 is modulated by combining the value of the series resistor R1 and that of the pulse width of the supply current via a clock signal delivered on an output pin PWM1 of the microcontroller 25 and the transistor Q1. Depending on the frequency of the clock signal, it is therefore possible to vary the intensity of the current supplying the LED 17, and therefore the intensity of the radiation emitted by the latter.

The optical flux received by the receiver photodiode 19, converted into intensity by the photodiode 19, is amplified in current thanks to a voltage current amplifier assembly, a low cost version of which is detailed in FIG. 7. The photonic current delivered by the photodiode 19 is amplified. by the bipolar transistor Q3 and converted into voltage by the resistor R8, this voltage being then amplified by the stage formed by the bipolar transistors Q5 and Q4. The stage comprising the two bipolar transistors Q6 and Q7 makes it possible to adapt the amplified voltage, an image of the flux reflected by the target object 26, the signal delivered on the output 30 of this stage being supplied to an input of the microcontroller 25 which is adapted to digitize this signal so as to form a digital voltage signal V 1. The detection of a target object 26 is performed by controlling the relative variation AV1 of the signal V1 (signal whose measurement can be performed synchronously by the microcontroller 25 just after the emission of the LED 17, itself also controlled by the microcontroller 25) with respect to a reference threshold 15 which is defined and modifiable in the embedded software of the microcontroller 25 by a memory input 28 The microcontroller 25 controls the emission and the periodic reading of the output 30 after the emission of each LED 17. It should be noted that this periodic reading can also be performed, e n variant, non-synchronously, especially permanently with a predetermined sampling frequency. In the example given above, setting at 50nA the variation of the intensity of the current delivered by the photodiode 19, the chain of signal processing by the circuit 21 must guarantee a gain greater than the conversion step of the analog converter 24. 25 assuming a conversion step of the millivolt order, the gain in voltage of the photoreceptor chain 19 must be greater than 106 what the chain presented (or consisting of an operational amplifier) low noise) achieves by the gain of the transistor Q3 and the value of the resistor R8 which is of the order of or greater than 105 Ohms. FIG. 4 gives an example of possible timing of a plurality of emitters 17 designated LED1, LED2,..., LEDn and the principle of selective detection of the received stream. As can be seen, each transmitter 17 emits an electromagnetic radiation detection pulse for a duration 8 which is the same for the different emitters in the example shown, but which could be variable depending on the emitter. Moreover, the successive pulses emitted by the same emitter 17 are separated by a period T. The duration 8 of each pulse is as short as possible and preferably less than 20, in particular of the order of or less than 10. . Such values make it possible in particular to distinguish the emitted electromagnetic radiation emitted from any parasitic radiation at high frequencies that may be in the environment, for example such as those emitted by neon lights, ballasts, the discharge of plasma screens. Indeed, these possible parasitic rays are in any case always emitted at frequencies below 20 kHz. It should also be noted that such a relatively short duration of the pulses makes it possible to supply the LEDs 17 with a relatively high electrical intensity, in particular substantially higher than the nominal intensity of continuous operation of such an LED. In practice, it is sufficient to ensure that the power supply is less than or equal to the continuous supply rating multiplied by the ratio T / 8. The pulses emitted by the various LEDs 17 are interleaved by the microcontroller 25, and phase shifted from one another successively. The period T is also chosen to be substantially greater than the duration 8 of the pulses, and preferably greater than n.8, n being the number of transmitters 17. In addition, the choice of the value of T is carried out on the one hand to ensure the detection of the arrival of an object 26 in the detection zone 16 well before this object 26 comes into contact with the display 11, on the other hand to minimize the energy consumption of the apparatus according to the invention when it is in the standby state, that is to say when the display 11 is not illuminated. In practice, very good results can be obtained by choosing a period T less than 1s-in particular of the order of or less than 0.1s-.

The signal delivered by the receiver 19 is represented in the upper part of FIG. 4. As can be seen, this signal has first of all slow variations, for example due to thermal re-emission effects in the same range of lengths. wave. For each pulse transmitted, the microcontroller 25 synchronously analyzes the variations in the amplitude of the signal. In the case of the first pulse shown in FIG. 4, no rapid variation is detected, so that the circuit considers that no object has entered the detection zone 16. In the example of the second pulse of the first transmitter 17, a rapid amplitude variation of the signal is detected, and if this variation is greater than the predetermined threshold AV1, the microcontroller 25 emits a signal 14 of presence representative of the presence of an object 26 in the detection zone 16. According to the phase of each pulse for which a detected presence, the microcontroller 25 can determine, from the signal received from the receiver 19, the location and the direction of movement of the object 26 in the detection zone 16. Such a detection method using very short pulses but of high intensity makes it possible to precisely adjust the detection distance d according to appropriate values, and this with standard electronic components, also makes it possible to detect with great reliability. the presence of an object such as a hand in the detection zone 16, while avoiding the various parasitic radiation 27 that may be encountered in the environment, and in particular the continuous or variable ambient light, external sources continuous heat, and possible parasitic reflections on fixed elements. It goes without saying that the invention can be the subject of many alternative embodiments and various applications, other than those mentioned above. In particular, the number of transmitter (s) and / or receiver (s) of each transmitter (s) / receiver (s) can vary. Also, several transmitter / receiver (s) assemblies may be provided, in particular emitting with different electromagnetic radiation (s) detection characteristics, for example a transmitter / receiver (s) assembly (s). ) emitting infrared radiation of wavelength less than 1 lm and other transmitter / receiver assembly (s) emitting infrared radiation of wavelength greater than 1 p, M. Furthermore, each transmitter and each receiver can be placed under the display 11 as shown, the latter being transparent to the electromagnetic detection radiation, and / or opposite the lights provided through the display screen, and / or at the periphery of the display 11 and outside the housing 10 so as to emit directly into the detection zone 16. The invention makes it possible to considerably increase the discretion of a central unit of home automation system, for example an alarm system, vis-à-vis the attacks by malicious users. Also, more generally, the invention makes it possible to confer on an apparatus of a home automation system an ergonomics that is particularly attractive to the user by triggering the lighting of the display 11 as soon as the latter approaches (normally voluntarily) his hand in the vicinity. immediate display. This result is also obtained by means of a very low power consumption, which is particularly important in case of power mains failure, especially in the case of a central unit of alarm system that works. then on batteries or accumulators.

Claims (12)

REVENDICATIONS1. Home automation system apparatus comprising a CLAIMS1 interface. A home automation system apparatus comprising a man / machine interface having a light display (11), a remote sensing device (15) and an electronic display control circuit (13, 25) (11) operable to control the display. extinguishing the display (11) according to predetermined criteria, and turning on the display (11) on receiving a signal delivered by said remote detection device (15), characterized in that said device (15) is adapted to: - selectively detect the presence of an object (26) only in a space zone, said detection zone (16), extending over a distance (d) non-zero detection of less than 1 m from said display (11), and for delivering a signal, said presence signal (14), representative of the selective detection of such a presence, and in that said circuit (13, 25) electronic control is adapted to control the ignition of said affic on receiving a presence signal (14) delivered by the remote sensing device (15); - being insensitive to the presence of an object (26) outside the zone (16) of detection. 2. Apparatus according to claim 1, characterized in that the device (15) for remote detection comprises at least one assembly (17, 19) 20 transmitter (s) / receiver (s) radiation, and is adapted to emit a signal (14) of presence on reception by said assembly (17, 19) of a flux corresponding selectively to a flux emitted by said assembly (17, 19) and reflected by an object (26) situated in said zone (16) detection. 3. Apparatus according to claim 2, characterized in that the device (15) for remote detection comprises at least one set (17, 19) transmitter (s) / receiver (s) comprising at least one transmitter (17) of electromagnetic radiation of predetermined specific characteristics and at least one receiver (19) capable of selectively detecting the reception of electromagnetic radiation corresponding to said predetermined specific characteristics. 4. Apparatus according to claim 3, characterized in that the device (15) for remote detection comprises at least one set (17, 19) transmitter (s) / receiver (s) comprising at least one transmitter (17) of radiation IEC 60050 - International Electrotechnical Vocabulary - Details for IEV number 841-21-86 Industrial electrohumic microscopy / Semiconductors / Electromagnetic fields and signals of central wave length between 0.76 p, m and li.tm and bandwidth less 5. Apparatus according to one of claims 2 to 4, characterized in that the device (15) for remote detection comprises at least one set (17, 19) transmitter (s) / receiver (s) comprising at least one transmitter (17) adapted to emit radiation pulses each having a duration of less than 20 seconds. 6. Apparatus according to one of claims 2 to 5, characterized in that the device (15) for remote detection comprises at least one set (17, 19) transmitter (s) / receiver (s) comprising at least one transmitter (17) adapted to emit radiation pulses separated by a duration of less than 1 s. 7. Apparatus according to one of claims 2 to 6, characterized in that the device (15) for remote detection comprises at least one set (17, 19) transmitter (s) / receiver (s) comprising at least two remote transmitters (17) and at least one receiver (19) interposed between the two transmitters. 8. Apparatus according to one of claims 1 to 7, characterized in that said display (11) is a backlit touch screen. 9. Apparatus according to one of claims 1 to 8, characterized in that it is in the form of a housing (10) having said display (11) on one of its faces whose appearance merges with that of the display (11), so that it is adapted so that said display (11) is, when off, not detectable at least at a viewing distance greater than said detection distance (d) - especially greater than lm-. 10. Apparatus according to one of claims 1 to 9, characterized in that said device (15) for remote detection is adapted to allow adjustment of the extension of said detection zone (16). 11. Home automation system comprising at least one device 30 according to one of claims 1 to 10. 12. Home automation system according to claim 11, characterized in that it is adapted to act as an alarm system and in that it comprises at least one central unit formed of an apparatus according to one of claims 1 to 10.