WIRELESS ELECTRONIC DETONATOR COMPRISING AN IGNITION SWITCH DIRECTED BY AN OPTICAL SIGNAL, WIRELESS DETONATION SYSTEM AND ACTIVATION PROCEDURE FOR SAID DETONATOR.

Abstract

A wireless electronic detonator (200) comprising a primary power source (230) and at least one functional module (250), an ignition switch (240) disposed between the primary power source and the functional module for connecting or disconnecting the functional module (250) and the primary power source (230), and an ignition switch control module (210) comprising an optical receiver (220) for detecting and demodulating a light signal (LU) emitted by a control console (100) and generating a control signal based on the demodulated light signal (LU) to direct at least the ignition switch (240); a wireless detonation system (10) comprising said wireless electronic detonator (200) and a control console (100) configured to emit a light signal (LU), and a method for activating said wireless electronic detonator.

Description

WIRELESS ELECTRONIC DETONATOR COMPRISING AN IGNITION SWITCH DIRECTED BY AN OPTICAL SIGNAL, WIRELESS DETONATION SYSTEM AND ACTIVATION METHOD FOR SAID DETONATOR The present invention relates to a wireless electronic detonator. The invention also relates to a wireless detonation system and an electronic detonator activation procedure. In this case, the activation procedure means turning the electronic detonator on or off, regardless of its ignition. The invention finds application in the field of pyrotechnic initiation, in any sector where a network of one or more detonators is traditionally required. Typical examples of use include mining, quarrying, seismic exploration, and the construction and public works sector. During use, electronic detonators are installed in designated locations, such as holes drilled in the ground, to receive and be loaded with explosives. The electronic detonators are then ignited according to a predetermined sequence. To achieve this result, an ignition delay is individually associated with each electronic detonator and a common firing command is transmitted to the network of electronic detonators with the help of a control console. This common firing order allows synchronizing the ignition delay countdown for the set of electronic detonators. Upon receiving the firing order, each electronic detonator manages the countdown of the specific ignition delay associated with it, as well as its own ignition. Wireless detonators are known, activated by a remote control console configured to communicate with the detonators via radio waves, for example, to exchange commands or messages regarding their status, or to send them an ignition command. Energy independence is therefore an important requirement for the realization of a wireless detonator. z / n;nn / zznz / e / YiAi WO 2019 / 073148 describes a wireless electronic detonator comprising a power source and functional modules, as well as first switching means arranged between the power source and the functional modules, enabling the power source to be connected or disconnected from the functional modules, and a control module for the first switching means comprising a radio energy recovery module configured to receive a radio signal from a control console, recover electrical energy from the received radio signal, generate an energy recovery signal representative of the level of electrical energy recovered, and generate at the output a control signal based on the recovered energy, said control signal directing said switching means. Thus, the control console sends a radio signal to the detonator. On the detonator side, the principle consists of recovering the energy present in the radio signal with the help of a suitable receiving system, i.e., the radio energy recovery module, in order to control an ignition switch mechanism. This solution offers the following advantages in particular: The activation process does not involve any mechanical elements to manipulate, which allows for the design of a completely watertight casing for the detonator, resistant to environmental conditions and tampering, and thus increasing the reliability of the system; The detonator can only be activated by a person who has the appropriate control console, thus limiting the possibility of it being activated by anyone who does not have the necessary equipment; The system is simple and quick to use: simply approach the detonator activation console to remotely power the switch system and start a wireless detonator control unit. However, this system has drawbacks. In particular, the range of the radio detonation system is quite limited. In practice, it does not exceed a few tens of centimeters due to radio power limitations imposed by regulations, which hinders its ease of use. Furthermore, it is not always possible to unambiguously target a specific detonator, especially when several detonators are close to one another. However, this discrimination is essential, as there is a risk of associating an inappropriate detonator with the firing plan, or of assigning an incorrect ignition delay to a detonator. Techniques based on proximity, antenna directivity, or estimating the distance between the activation console and the detonator exist—for example, those proposed in WO 2019 / 073148—but their implementation is complex. In this context, one objective of the present invention is to overcome, at least in part, the aforementioned drawbacks, and may also give rise to other advantages. Specifically, the object of the present invention is to provide a remote activation technique that offers a more effective solution to the problems mentioned above. In particular, the object of the present invention relates to a switch control system, i.e., the mechanism that allows the detonator to be activated or not. To that effect, according to a first aspect of the invention, a wireless electronic detonator is proposed comprising a primary power source and at least one functional module, an ignition switch, arranged between the primary power source and the functional module, configured to connect or disconnect the functional module and the primary power source, and an ignition switch control module, characterized in that the ignition switch control module comprises an optical receiver configured to detect and demodulate a light signal emitted by a control console and generate at the output a control signal as a function of the demodulated light signal, the control signal being configured to direct at least the ignition switch. Thus, the detonator is configured to receive and demodulate the light signal received from the control console (also called the remote activation console). When the light signal is correctly demodulated, the ignition switch is activated and the rest of the electronic components of the detonator are turned on. The primary power source is configured to power the other z / n;nn / zznz / e / YiAi detonator elements via the ignition switch. This includes, for example, an on-board power source, or an energy recovery module combined with local energy storage, or a wired power supply module. The primary power source is also configured, for example, to transfer energy to a dedicated energy storage element to fire an explosive initiator of the functional module. The ignition switch may be similar to one of the embodiments set out in document WO 2019 / 073148. The ignition switch comprises, for example, a switch. According to the invention, the detonator comprises an ignition switch control module, i.e., a control module configured to direct the ignition switch. Thus, the control module is configured, for example, to receive an ignition command and order the ignition of the explosive initiator in accordance with that ignition command. For this purpose, the control module mainly comprises the optical receiver. In a preferred embodiment, the optical receiver comprises an optical detector configured to detect the light signal emitted by the control console and convert the light signal into an electrical signal. For example, the optical detector comprises a photodiode, possibly combined with a sensing resistor. In a preferred embodiment, the detonator further comprises a demodulator configured to demodulate the electrical signal. According to one embodiment, the demodulator comprises an analog conditioner configured to transform the electrical signal from the optical detector, which is analog, into a digital signal. The analog conditioner comprises, for example, at least one high-pass filter, configured to suppress a static component of the light beam, or even a band-pass filter. According to one embodiment, the demodulator comprises a digital processing module configured to demodulate the digital signal, for example, in order to detect the binary sequence emitted by the control console, yz / n;nn / zznz / e / YiAi, and generate a control signal to direct the ignition switch, for example, based on the binary sequence. The digital processing module comprises, for example, at least one computer and possibly a memory element. In this case, a memory element designates both a conventional memory and a record. For example, the received signal is correlated with a reference signal, for example, recorded in the memory element, to detect an activation sequence. Based on the result of the correlation, the digital processing module is configured to generate a control signal for the ignition switch. In all cases, the optical receiver presented here needs to be powered. However, ideally the detonation system should consume as little energy as possible, to avoid reducing the detonator's autonomy before its use in the field and to preserve as much energy as possible from the primary energy source. Therefore, consumption should be as low as possible. The power consumption of the optical detector and the digital processing module should be reduced as a priority, in order to aim for a system consumption on the order of a few microamps, if possible. The optical detector generally has a power consumption that is directly proportional to the illumination. According to a first example, the detonator advantageously comprises at least one optical filter upstream of the optical detector, in order to reduce the intensity of the ambient lighting, without reducing the detection performance. One of the objectives is to maximize the received light power corresponding to the optical signal, while minimizing the received power corresponding to ambient lighting. This allows reducing the current consumed by the optical detector due to the intensity of the ambient light. According to a second example, the optical detector advantageously comprises a photovoltaic element. z / n;nn / zznz / B / YiAi The detector is then used, in this case, in photovoltaic mode. For this purpose, for example, it is not polarized by a supply voltage. This type of setup allows one to possibly completely avoid the consumption of the optical detector. In this way, consumption is very well regulated and is more independent of the ambient lighting conditions. According to a third example, the detonator comprises a low-power mode configured to cut off the power supply to at least the digital processing module, thus limiting the system's electrical consumption. Thus, for example, under natural lighting conditions, the light intensity varies slowly, so there are no changes in the output of the analog conditioner, due to the effect of high-pass filtering. As soon as there is a sudden change in lighting, a transition appears in the output of the analog conditioner, which is used to trigger the digital processing module. This functionality can typically be implemented using a low-power mode of a microcontroller. The consumption can thus be reduced to less than one microampere (1 μA). According to a fourth example, in order to avoid any residual consumption during a storage period of the detonator, for example (which may last several months before use), a light level-dependent power cut-off of the optical receiver is used (dark mode). The detonator then comprises, for example, a general cutoff module configured to cut off a feed to the optical receiver. The general cutoff module comprises, for example, a high-gain phototransistor (e.g., 40 μA / 100 Lux), possibly coupled to a sensing resistor configured to detect a very low illumination level, typically less than 100 Lux, even 80 Lux, even 60 Lux, even 40 Lux, even 20 Lux, or even 1 Lux. The detonator, or even the general cutoff module, for example, also comprises, for example, a transistor, which acts as a switch, and the sensing resistor is configured to direct the transistor. Thus, when the detonator is in the dark, stored in a box, for example, the power supply to the optical receiver is completely cut off. Therefore, the consumption is almost zero (with the exception of the leakage currents of the transistor and the phototransistor, which are negligible). When the detonator is removed from the box for use, the main cutoff module turns on the optical receiver, leaving the detonator waiting for optical activation by the user (via the control console). In this case, the functional module comprises, for example, at least one explosive initiator. According to an interesting embodiment, the functional module also comprises an energy storage element dedicated to the ignition of the explosive initiator. For safety, the functional module also advantageously comprises an energy storage element isolation switch configured to activate or deactivate the energy transfer from the primary energy source to the energy storage element. Also for safety, the functional module may also include a discharge device, configured to slowly discharge the energy storage element in order to return to a safe state in case of detonator shutdown, for example. According to an interesting option, the functional module can then also comprise an ignition switch configured to allow energy transfer between the energy storage element dedicated to ignition and the explosive initiator. According to one embodiment, the functional module also comprises a computer configured to control the operation of the detonator. For example, the computer is connected to or disconnected from the primary power source by means of the power switch. Thus, the computer is configured, for example, to receive a signal and order the ignition of the explosive initiator of the functional module in accordance with that signal. According to another interesting option, the detonator is configured to emit a return signal when the detonator's optical receiver has detected at least the light signal emitted by the control console. The user may, for example, be warned that the light signal z / n;nn / zznz / e / YiAi emitted by the control console has been detected by at least the target detonator. Thus, the detonator is ignited by optical activation. For example, the detonator is configured to emit a return signal directly perceptible to the user, for example, a visual or auditory signal. According to another example, the detonator is configured to emit a return signal configured to be picked up accordingly by the control console, for example, a radio signal. This detonator offers at least the same advantages as the previously cited prior art, in particular: In terms of reliability: it allows for a watertight casing and the elimination of any mechanical elements, limiting or even preventing the risks of false contact, etc. In terms of safety: it is necessary to have the appropriate control console (which includes the light source) to activate the detonator, or in terms of ease and speed of implementation: it is not necessary to physically and electrically connect a control console to the detonator to activate it and the activation is carried out without contact. Furthermore, a detonator of this type also has at least the advantage of facilitating a simplified mode of operation thanks to the range of remote activation: for example, it is not necessary to use an accessory to activate a detonator, for example, a pole to activate a detonator on the ground without having to bend down, or a basket to activate a detonator placed at the top of an underground gallery. Also proposed, according to a second aspect of the invention, is a wireless detonation system comprising a wireless electronic detonator, which has at least some of the aforementioned characteristics, and a control console configured to emit a light signal intended for said wireless electronic detonator. In practice, a user then directs the light signal towards the detonator they wish to activate. The wireless detonation system has similar characteristics and advantages to those described above in relation to the wireless electronic detonator. z / n;nn / zznz / e / YiAi Furthermore, a detonator of this type associated with a corresponding control console also presents at least the following advantages: In terms of range: the range is increased, allowing in practice the detonator to be activated from several meters away, depending on the ambient light and the power of the light source. In terms of regulations: the system is not subject to restrictive regulations like those of the radio-activated system described in the prior art, which allows for the development of a more efficient system. In terms of safety: the control console allows precise aiming at the desired detonator, and the direction of the light beam can be perfectly visible to the user if the signal is emitted within the visible range, thus avoiding any ambiguity. In terms of flexibility, the system can be adapted to use cases other than the standard one. Indeed, simultaneous activation of a group of detonators is possible, using a wider focal distance that allows multiple detonators to be illuminated. This technique can be advantageous in an underground environment, or when the firing plan has already been established and the objective is to activate multiple detonators very quickly. In a particularly convenient embodiment, the control console comprises a light source, configured to emit the light signal. The light source is preferably configured to emit a light signal in the visible range, i.e., a light signal with a wavelength between approximately 400 and 800 nm. However, the light signal can also be emitted in the infrared (IR) or ultraviolet (UV) range depending on the application's needs. The techniques used are identical. Compared to the visible range, a light signal emitted in the IR or UV range is not perceptible (visible) to the user, which can make the detonation system less easy to use, especially for targeting a specific detonator. To overcome this difficulty, the detonation system then advantageously includes a aiming aid system. However, a aiming aid system can also be useful when using a signal in the visible range. ζ / η;ηη / ζζηζ / Β / γΐΛΐ For example, depending on the power of the optical beam or if the ambient light is high, the light signal may be less noticeable. This makes aiming at a detonator more difficult for the user. In a practical example, the control console comprises a detector configured to detect the return signal emitted by the detonator. According to one interesting option, the control console also comprises a warning device configured to emit a warning signal, for example, visual or audible, which allows the user to be warned that the light signal emitted by the light source has been detected by at least the target detonator, or to indicate that the return signal has been detected by the control console. The control console then comprises, for example, an LED or a buzzer. Such a detonation system configuration then forms a aiming aid system. The detonator is then configured, for example, to emit a return when illuminated by the beam from the control console. Thus, in an interesting example of implementation, the control console is configured to emit a light signal continuously, either for a predetermined period of time or at the user's request. The user illuminates the area where the detonator is located, or more specifically, the detonator's optical receiver, with a sweeping motion. When the detonator detects the expected light sequence, it triggers a simple visual response, for example, using an LED, or an audible response, for example, using a buzzer. According to another interesting option, the control console also includes a focal distance configured to focus the light signal towards at least one detonator. In this case, the focal length refers to an optical focal length, called adjustable or variable. The use of such a focal length allows for greater system flexibility. For example, it is then possible to simultaneously activate a group of detonators, using a wider focal distance that allows several detonators to be illuminated. z / n;nn / zznz / e / YiAi This technique can be beneficial in an underground context, or when the firing plan has already been established and the objective is to activate several or all of the detonators very quickly. In terms of safety, the focal distance used on the control console allows precise aiming at the desired detonator or detonators. In another embodiment, the control console further comprises a modulator configured to modulate the light signal according to at least one modulation pattern. Thus, the light signal can be modulated with a modulation pattern that allows it to be distinguished from ambient lighting, natural or artificial, in order to prevent the detonator from being activated unexpectedly. Thus, advantageously, the modulated light signal comprises at least one activation sequence. One advantage of the detonation system that uses optical modulation is that it is possible to use the modulated signal to send useful digital data to the detonator. It allows, for example: Directly transfer the ignition delay to the detonator during its activation via optical means. Provide the identifier of the console from which the detonator was activated or the identifier of the ignition console to be used, allowing multiple teams to simultaneously deploy detonator networks in the same area. Provide a specific ignition code for the detonator, thus preventing accidental firing of detonators that do not have the specified code. Thus, for example, the modulated light signal comprises a sequence of data configured to send instructions to the detonator, for example, a delay value, and / or an identifier, and / or an ignition code, or others. The data sequence is transmitted after the activation sequence in the light signal. Furthermore, in the case of a light beam emitted in the visible range, the target detonator is visually identified by the user and the information can hardly be intercepted or encoded, making the system more secure. According to another interesting option, the modulated light signal comprises a stop signal. In order to fulfill the same function as a manual switch, the detonation system that uses optical modulation allows, preferably, the deactivation of a detonator. This offers an additional level of safety, in case, for example, you decide to abandon the firing, or simply to stop a detonator that has been accidentally ignited. To use this stop function, two different sequences can be used: one sequence for turning it on and another sequence for turning it off. Accordingly, the control console comprises, for example, a selection module, configured to allow the user to select one sequence or another (i.e., an activation sequence or a stop sequence). Finally, according to a third aspect, a procedure for activating a wireless electronic detonator is proposed, comprising a primary power source, at least one functional module, an ignition switch arranged between the primary power source and the functional module, configured to connect or disconnect the functional module and the primary power source, and an ignition switch control module. According to the invention, the procedure comprises the following steps: Reception of a light signal; Demodulation of the received light signal; Generation of a control signal, in accordance with the demodulated light signal, the control signal being configured to direct at least the ignition switch. Thus, the functional module of the electronic detonator is activated, or turned on, by means of the ignition switch, arranged between the primary power source and the functional module, which is controlled by a control signal generated when the demodulated light signal corresponds at least to the activation instructions of the electronic detonator. The activation procedure has similar characteristics and advantages to those described above in relation to the wireless electronic detonator z / n;nn / zznz / B / YiAi and the wireless detonation system. According to an advantageous embodiment, the light signal reception stage comprises a light signal detection stage and a light signal conversion stage into an electrical signal. According to an advantageous embodiment, the demodulation stage comprises a stage for transforming the electrical signal into a digital signal and a stage for identifying at least one activation sequence in the digital signal. If an activation sequence is identified, the stage of generating a control signal comprises a stage of activating the ignition switch. For example, if the digital signal corresponds to a reference signal comprising at least one activation sequence, the power switch is activated. In this case, activation refers to the switching on or off of the electronic detonator, regardless of its ignition, i.e., its handling. According to one interesting option, the demodulation stage also includes a stage of identifying at least one data sequence in the digital signal. If a data sequence is identified, the stage of generating a control signal comprises a stage of generating instructions corresponding to the data sequence. For example, once an electronic detonator is switched on, an ignition delay can be associated with it. This association can be carried out immediately or after a period of time following the switch-on. According to different implementations, the power-on and delay association can be performed with the same control console or with different control consoles. Thus, the deployment of electronic detonators can be carried out in different ways. In the case of association of the delay with different control consoles for ignition and delay association, the ignition can be carried out at the time of installation, and the delay association can be carried out at a later time, once all the detonators have been ignited. In the case of delayed delay association, all electronic detonators are initially activated upon installation via the control console. The electronic detonators can then be placed in a standby or standby state using a periodic activation procedure. Once all electronic detonators are installed and activated, delays are associated with each one. For this purpose, the electronic detonators can be equipped with any location system (e.g., GPS, a system for measuring relative distances or received power between each electronic detonator in the network, which may require further processing, etc.). The raw data relating to each electronic detonator (e.g., absolute position, relative distances, or received power, etc.) is then processed.This information is collected, for example, via radio from the control console, in order to create a map of the electronic detonator network with its identifiers. Knowing this map, it is possible to assign a delay to each electronic detonator. If an inconsistency is observed between a planned firing plan and the actual map of the electronic detonators, this can be detected, allowing the detonators that exhibit such inconsistency to be turned off. When ignition and delay association are performed using different control consoles, these two operations occur at widely separated times, ranging from a few minutes to several hours, or even several days, depending on the situation. Deactivation conditions can be considered in the interim to allow the electronic detonator to return to an off state. For example, if no activation signal is requested within a specified time, or if no messages are exchanged or received with the control console during the electronic detonator's periodic activation operations, the digital processing module can turn off the electronic detonator. Ultimately, each of these approaches ends with the execution of a conventional ignition procedure. The invention, according to one embodiment, will be fully understood and its advantages more evident after reading the following detailed description, which is provided for informational purposes only and not by way of limitation, with reference to the accompanying drawings in which: z / n;nn / zznz / B / YiAi [Fig. 1] Figure 1 schematically shows a detonation system according to an embodiment of the invention; [Fig. 2] Figure 2 represents an example of a pseudorandom sequence following a modulation pattern; [Fig. 3] Figure 3 represents a wireless detonator according to an embodiment of the invention; [Fig. 4] Figure 4 shows an embodiment of an optical receiver; [Fig. 5] Figure 5 illustrates a first embodiment of an optical receiver; [Fig. 6] Figure 6 schematically represents an example of the emission spectrum of an LED-based light source as a function of wavelength; [Fig. 7] Figure 7 schematically represents the spectral sensitivity of a photodiode as a function of wavelength; [Fig. 8] Figure 8 represents the spectral characteristics of a filter resulting from the emission spectrum of Figure 6 and the sensitivity of the photodiode of Figure 7 as a function of wavelength; [Fig. 9] Figure 9 illustrates a second embodiment of an optical receiver; [Fig. 10] Figure 10 illustrates a third embodiment of an optical receiver. The identical elements shown in the figures mentioned above are identified with identical numerical references. According to an embodiment of one aspect of the invention shown schematically in Figure 1, a detonation system 10 mainly comprises: a control console 100 configured to emit a modulated light signal LU, and an energy-independent detonator 200 configured to detect and demodulate the light signal LU from the control console 100. According to one embodiment, the control console 100 comprises a modulated light source. As shown schematically in Figure 1, the control console 100 comprises, for example, a light source 110 configured to emit a light beam comprising a light signal and a modulator 120 configured to modulate the light signal according to at least one modulation pattern. z / n;nn / zznz / e / YiAi The light source 110 is preferably configured to emit a light signal in the visible range, i.e., a light signal with a wavelength between approximately 400 and 800 nm. However, a light source configured to emit a signal in the infrared or ultraviolet range can be used, depending on the needs or the intended application. According to an unshown option, the control console may also include a variable focal distance, also called adjustable, configured to focus the light signal towards one or more detonators. The control console can then activate a single detonator, for example, if the focal distance is adjusted to transmit a narrow beam, or simultaneously activate a group of detonators, if the focal distance is adjusted to transmit a wider beam that allows several detonators to be illuminated. According to one interesting option, the detonator is configured to emit a return signal when illuminated by the beam from the control console. The detonator includes, for example, a visual or audible warning device. The detonator can also be configured to emit a return signal configured to be picked up accordingly by the control console, for example, a radio signal. According to at least one other interesting option, the control console 100 may also comprise a detector, configured to detect a return signal emitted by the detonator, and a warning device, for example visual or audible, configured to warn the user that the light signal emitted by the light source 110 has been detected by at least the target detonator, or that the return signal has been detected by the control console. The warning device, whether from the control console or the detonator, comprises, for example, an LED or a buzzer. The detonation system is then equipped with a aiming aid system. The control console preferably emits the light sequence continuously, either for a predetermined period of time or at the user's request. The user illuminates the area where the detonator 200 is located, or more particularly, an optical receiver 220 of the detonator 200 (described below), with a sweeping motion. When the detonator detects the expected light sequence, it triggers a simple visual response, for example, using an LED, or an audible response, for example, using a buzzer. Figure 2 represents an example of modulation pattern M used to modulate the light signal LU emitted by control console 100. In particular, this figure shows a pseudo-random sequence of OOK (On / Off Keying) modulation, but other types of optical modulations can be considered. An OOK-type modulation has the advantage of being simple to implement and not complex to demodulate, which allows limiting the cost of the detonator. Preferably, a pseudo-random sequence known to the receiver is used to modulate the optical signal emitted by the console, in order to be able to distinguish it with the least possible error from natural or artificial light (in fact, certain artificial lightings present a broken signal in the shape of a crenellation). The size of the pseudorandom sequence must be long enough, usually greater than 32 bits, in order to avoid false alarms. Preferably, the modulation speed (frequency) is normally between 100 Hz and 10 kHz. This value is sufficient to not be too sensitive to user movements, and is not too high so as to limit the cost of the receiver 220 by using, for example, a photodiode 231 (shown schematically in Figure 5) of limited performance. This example is not exhaustive. Other types of modulation, other types of sequences, and other modulation rates could be used. Another advantage of the optical modulation system is the ability to use the modulated light signal to transmit information, i.e., digital data, useful to the detonator, via the optical pathway. For this purpose, in the control console, the modulated light signal LU preferably comprises, for example, an activation sequence that exhibits good autocorrelation properties, typically a sequence of Kasami. This allows the receiver, i.e., the detonator, to synchronize correctly with the received signal in order to extract the data. The data sequence comprises, for example, binary data that is simply concatenated following the activation sequence. The message sent by the control console comprises, for example, the following sequences: [activation sequence] - [data sequence]. The data sequence is configured to send, for example, a delay value, and / or an identifier, and / or an ignition code, or others. According to one example, optionally, a CRC (Cyclic Redundancy Check) integrity check can be added to the message, in order to verify the result of the demodulation of the data sequence in the detonator (i.e., the receiver). The message sent by the control console then comprises, for example, the following sequences: [activation sequence] - [data sequence] - [verification sequence]. According to another example, it would also be possible to add a correction code. The message sent by the control console then comprises, for example, the following sequences: [activation sequence] - [data sequence] - [verification sequence] - [correction sequence]. Thus, according to an implementation example, it is possible to use a "Hamming" type block code, which comprises a data sequence and a correction sequence. On the receiver side, i.e., on the detonator side, conventional digital demodulation techniques can be used. The activation sequence allows the receiver to be synchronized with the start of the sent message. Next, a simple regular sampling, or edge detection, allows the message content to be demodulated. According to another interesting option, the modulated light signal LU comprises a stop signal. In order to fulfill the same function as a manual switch, the detonation system that uses optical modulation allows, preferably, the deactivation of a detonator. z / n;nn / zznz / e / YiAi This offers an additional level of safety, in case, for example, you decide to abandon the firing or simply to stop a detonator that has been accidentally ignited. To use this stop function, two different sequences can be used: one sequence for turning on and another sequence for turning off. The two sequences are, preferably, almost orthogonal, in order to limit the risks of erroneous detection of the emitted sequence. For example, two different Kasami sequences can meet this condition. One variant can be to use the sign of the sequence: emitted normally, the sequence leads to a peak of positive correlation for starting, but emitted in reverse, it provides a peak of negative correlation, for example, for stopping. In the end, only one correlator is needed, and only the sign of the result makes the difference. However, Kasami sequences are preferred because they provide a close to 0 result for intercorrelation, regardless of the offset between the sequences. Therefore, the control console must allow the user to select one sequence or another (i.e., an activation sequence or a stop sequence). At the receiver level, a digital processing module of the detonator's optical receiver (described below) is configured, for example, to detect one sequence or the other. The correlation operations are duplicated, for example, by alternately using one sequence and then the other as the reference sequence. Figure 3 shows an embodiment of a 200 detonator. The detonator 200 according to the invention, which is energy autonomous, mainly comprises, in this case, a control module 210 that includes an optical receiver 220 configured to activate the detonator optically. The optical receiver 220 allows, in particular, the demodulation of the light beam LU sent by the console 100 and the generation of a control signal for the power switch 240. Furthermore, the detonator 200 comprises, for example, in this case, the following elements: A primary power source 230 (for example, an onboard power source, or an energy recovery module combined with local energy storage, or a wired power supply module), enabling the different elements of the detonator to be powered via an ignition switch 240 and energy to be transferred to an energy storage element 253 dedicated to the ignition of an explosive initiator 256. The power switch 240, comprising, for example, a switch K10, which allows the control of the power-up of different electronic elements of a functional module 250 from the primary power source 230. This power switch 240 may be similar to one of the embodiments set out in document WO 2019 / 073148. And the functional module 250. Functional module 250 comprises, in this case, for example, the following electronic elements: A computer 251 allows control of the operation of the electronic detonator. The computer 251 is connected to or disconnected from the primary power source 230 by means of the ignition switch 240. The energy storage element 253 dedicated to the ignition of the explosive initiator 256. An isolation switch 252 of the energy storage element, comprising, for example, a switch K20, enabling the energy transfer from the primary energy source 230 to the energy storage element 253 to be activated or deactivated, independently of the energy transfer from the primary energy source 230 to the computer 251. A discharge device 254, which forms a safety mechanism that allows a slow discharge of the energy storage element 253 dedicated to ignition, in order to return to a safe state in case of deactivation. An ignition switch 255 comprising, for example, a K30 switch, which allows the transfer of energy between the energy storage element 253 dedicated to ignition and the explosive initiator 256. z / n;nn / zznz / e / YiAi And the explosive initiator 256. The optical receiver 220 according to an example embodiment is shown schematically in Figure 4. The optical receiver 220 of Figure 4 mainly comprises: an optical detector 221, configured to convert the received light signal LU into an electrical signal; and a demodulator 222 configured to demodulate the received light signal and generate a control signal for the power switch 240. In this case, the 222 demodulator includes, for example: an analog conditioner 223, configured to transform the electrical signal from the optical detector 221, which is analog, into a digital signal; and a digital processing module 224, configured to demodulate the digital signal in order to detect the binary sequence emitted by the control console 100 and generate a control signal to direct at least the power switch 240 according to the binary sequence. In this case, the digital processing module 224 and / or the computer 251 are configured, for example, to: manage the operation of the electronic detonator 200; analyze the messages received through the control console 100; act in accordance with the meaning of the messages received; activate energy storage in energy storage element 253 for ignition; perform the ignition delay countdown associated with the electronic detonator 200; activate the energy transfer from the energy storage element 253 to the explosive initiator 24 at the end of the countdown, by means of the ignition switch 255; activate the download device 254; direct the ignition switch 240; direct the isolation switch of energy storage element 252... Figure 5 represents an embodiment of the 220 optical receiver shown schematically in Figure 4. z / n;nn / zznz / e / YiAi The optical detector 221 comprises, in this case, a photodiode 231 that converts the light signal LU into an electrical current. The optical detector 221 also includes in this case a detection resistor 232 that allows processing a voltage that can be used by the analog conditioner 223. The detection resistor 232 is sized so that the signal does not saturate under bright light conditions, which would render the system inoperable. Conversely, a value that is too low reduces the dynamics of the electrical signal, thus decreasing the range of the detonation system. Assuming a maximum possible illumination of Emax (normally 130,000 Lux), a photodiode sensitivity of SA / Lux 231, and a supply voltage Vdd, the detection resistor 232, of the resistor indicated as R, must verify the relationship Vdd = R x S x Emax, to be at the saturation limit under maximum illumination conditions. Therefore, the sizing of the pair [photodiode 231 - sensing resistor 232] largely determines the system's performance in terms of range. The analog conditioner 223 comprises, in this case, at least one high-pass filter, in order to suppress the static component linked to natural lighting and user movements. It may include a bandpass filter (which then corresponds to a high-pass filter combined with a low-pass filter) to equally suppress possible high-frequency interference. In the implementation example shown in Figure 5, the analog conditioner 223 comprises a bandpass filter (an R1C1 (resistance-capacitor) pair in a + (plus) branch of a comparator 233 determines the high frequency and an R2C2 pair in a (minus) branch, the low frequency) which allows the static component of the signal, linked to ambient lighting, to be suppressed. The filtered signals are injected into comparator 233 to obtain a binary signal at the output of comparator 233 and, therefore, at the output of analog conditioner 223. The analog conditioner 223 comprises, for example, a comparator and / or an operational amplifier. z / n / nn / zznz / e / YiAi Finally, the digital processing module 224, into which the digital signal is injected, comprises, for example, at least one computer (usually a microcontroller or a dedicated digital circuit) and possibly a memory element. The received signal is correlated with the expected reference signal to detect the presence of an activation signal. The expected reference signal may be previously recorded in the digital processing module 224. At this level, any known digital signal demodulation technique can be used. When the activation sequence is detected, the digital processing module 224 generates a control signal configured to direct the ignition switch 240 to the active position, for example, to the closed position if it is a switch, in order to activate the other elements of the detonator. However, these functionalities can be implemented differently from the realization shown schematically in Figure 5. For example, in order to share hardware resources, it is possible, for example, to perform digital processing in computer 251 of functional module 250. The general architecture must then be slightly revised, to mount computer 251 upstream of power switch 240. In other words, the computer 251 of the functional module 250 and the digital processing module 224 can then be grouped into a single entity, preferably located upstream of the power switch 240, for example, in the optical receiver 220. In addition, part of the computer may remain inactive (in low power mode) until the light sequence has been received. It is also possible to use other strategies to demodulate the light signal, which leads to a different hardware architecture for the optical receiver 220. For example, the analog conditioner 223 could be replaced by digitization using a CAN (analog-to-digital converter) of the raw signal from the optical detector, which can then be processed directly by the computer in the digital processing module 224. In all cases, the optical receiver presented needs to be powered. However, ideally the detonation system should consume the least amount of energy possible, to avoid reducing the detonator's autonomy before its use in the field. Therefore, consumption must be as low as possible for the system to have the greatest possible practical interest. The 220 optical detector generally has a consumption that is directly proportional to the illumination. Typically, for a photodiode with a sensitivity of 40 nA / 100 Lux, the consumption is 52 μA under maximum illumination conditions of 130,000 Lux. The power consumption of the analog conditioner 223 is normally between 1 mA and 30 mA depending on the comparator or operational amplifier used. Choosing a comparator 233 with a reduced [gain x bandwidth] product allows selecting components whose consumption is around one microampere (μA). This reduces the allowed modulation speed, but it is not a critical element of the system. Finally, the 224 digital processing module typically consumes several milliamps when processing is performed. The power consumption of the optical detector 221 and the digital processing module 224 are therefore the ones that should be reduced as a priority, in order to aim for consumption on the order of a few microamps, if possible. One approach then consists, for example, of adding an optical filter in front of the photodiode 231 of the optical detector 221, in order to reduce the intensity of the ambient light, without reducing the detection performance. The objective is to maximize the received light power corresponding to the optical signal, while minimizing the received power corresponding to ambient lighting. This allows reducing the current consumed by the optical detector due to the intensity of the ambient light. The light source of the control console 100 has a very particular emission spectrum (Fig. 6), and the photodiode 231 has a characteristic spectral sensitivity (Fig. 7). These two elements therefore behave as gain filtering stages Gtx(A) and Grx(A), depending on the wavelength λ of the light signal emitted by the control console 100. z / n;nn / zznz / e / YiAi The optical power Prx converted by the photodiode 231 into electrical power is therefore expressed as a function of the power Ptx emitted by the console, the attenuation linked to the distance R, the illuminated solid angle Ω, and the respective gains Gtx and Grx, according to the following formula: Prx = [(Grx.Gtx) / QR2].Ptx For a given distance and focal length, the received power is maximum when the gain (Gtx.Grx) is maximum, i.e., for a given wavelength λ (Fig. 8). Adding an additional filter around this wavelength allows maximizing reception at this wavelength and reducing reception at other wavelengths, which corresponds to the intended objective. Next, the optimal width of the optical filter is calculated based on the filter's response to natural light, which is to be reduced. In practice, it is possible to reduce the power consumption of the optical detector by a factor of 3. A second approach consists, for example, in using the photovoltaic effect of a photodetector 234 for the optical detector 221. The photodetector 234 is used, in this case, in photovoltaic mode, as in the setup shown schematically in figure 9. For this reason, it is not polarized by a supply voltage. A photodiode like the one in the previous example cannot generate enough current to be used. It is necessary to increase the surface area of ​​the photosensitive element, using a small photovoltaic panel, or several photodiodes in parallel. This setup allows us to avoid, possibly completely, the consumption of the optical detector. In this way, consumption is very well regulated and is more independent of the ambient lighting conditions. According to a third approach, it is also possible to cut off the power supply to the digital processing module in order to limit consumption. For example, the 224 digital processing module includes a low-power mode that allows the clock and possibly the power supply to the digital electronic components to be switched off. For example, the presence of a state change in the digital signal at the z / n;nn / zznz / e / YiAi comparator output is used to take the system out of low power mode. Thus, under natural lighting conditions, the light intensity varies slowly, so there are no changes in the output of the analog conditioner, due to the effect of low-pass filtering. As soon as there is a sudden change in lighting, a transition appears in the output of the analog conditioner, which is used to trigger the digital processing module. This functionality can typically be implemented using a low-power mode of a microcontroller. The consumption can thus be reduced to less than one microampere (1 μA). According to a fourth approach, to avoid any residual consumption during a storage period of the detonator, for example (which may last several months before use), a general power cut-off dependent on the lighting level (dark mode) is used. As shown in Figure 10, an additional stage of light level detection is used, with an adjustment that allows the output signal to be voluntarily saturated as soon as a very low light level appears. For this purpose, the additional stage of detecting the illumination level comprises, for example, a high-gain phototransistor 235 (for example, 40 μA / 100 Lux) and a detection resistor 237, the setting of which allows the detection of a very low illumination level, typically a few tens of Lux. The voltage across the terminals of the detection resistor 237 allows a transistor 236 to be directed, which acts as a switch. Thus, the optical detection stage 221 remains unchanged. An additional stage is added before this one (but based on the same principle), this additional stage having a different setting than the optical detection stage. Thus, when the detonator is in the dark, stored in a box, for example, the power supply is completely cut off. Power consumption is therefore almost zero (with the exception of the leakage currents of transistor 236 and phototransistor 235, which are negligible). When the detonator is removed from the box for use, the general cut-off stage turns on the 220 optical receiver, leaving the detonator at z / n;nn / zznz / e / YiAi awaiting optical activation by the user (via the control console).

Claims

CLAIMS 1. A wireless electronic detonator (200) comprising a primary power source (230) and at least one functional module (250), an ignition switch (240) disposed between the primary power source (230) and the functional module (250), configured to connect or disconnect the functional module (250) and the primary power source (230), and a control module (210) for the ignition switch, CHARACTERIZED in that the functional module (250) further comprises at least one explosive initiator (256) and an energy storage element (253) dedicated to igniting the explosive initiator (256), and in that the control module (210) for the ignition switch comprises an optical receiver (220) configured to detect and demodulate a light signal (LU) emitted by a control console (100) and generate at the output a control signal as a function of the demodulated light signal (LU),with the control signal configured to direct at least the ignition switch (240)., 2. Detonator (200) according to claim 1, CHARACTERIZED in that the optical receiver (220) comprises an optical detector (221) configured to detect the light signal (LU) emitted by the control console (100) and convert the light signal (LU) into an electrical signal.

3. Detonator (200) according to claim 2, CHARACTERIZED in that the detonator comprises at least one optical filter upstream of the optical detector (221).

4. Detonator (200) according to any one of claims 2 or 3, CHARACTERIZED in that the optical detector (221) comprises a photovoltaic element (234).

5. Detonator (200) according to any one of claims 1 to 4, CHARACTERIZED in that the detonator comprises a demodulator (222) configured to demodulate the electrical signal. z / n;nn / zznz / e / YiAi 6. Detonator (200) according to claim 5, CHARACTERIZED in that the demodulator (222) comprises an analog conditioner (223) configured to transform the electrical signal from the optical detector (221) into a digital signal.

7. Detonator (200) according to claim 6, CHARACTERIZED in that the demodulator (222) comprises a digital processing module (224) configured to demodulate the digital signal, and generate a control signal to direct the ignition switch (240).

8. Detonator (200) according to claim 7, CHARACTERIZED in that the detonator comprises a low power mode configured to cut off the power supply to at least the digital processing module (224).

9. Detonator (200) according to any one of claims 1 to 8, CHARACTERIZED in that it comprises a general cutoff module configured to cut off a feed to the optical receiver (220).

10. Detonator (200) according to claim 9, CHARACTERIZED in that the general cutoff module comprises a high-gain phototransistor (235), coupled to a detection resistor (237) configured to detect a very low level of illumination, and a transistor (236), which acts as a switch, the detection resistor (237) being configured to direct the transistor (236).

11. Detonator (200) according to any one of claims 1 to 10, CHARACTERIZED in that the detonator is configured to emit a return signal when the optical receiver (220) has detected at least the light signal (LU) emitted by the control console (100).

12. Wireless detonation system (10) CHARACTERIZED in that it comprises a wireless electronic detonator (200) according to any one of claims 1 to 11, and a control console (100) configured to emit a light signal (LU) intended for said wireless electronic detonator z / n;nn / zznz / e / YiAi (200).

13. Detonation system (10) according to claim 12, CHARACTERIZED in that the control console (100) comprises a focal distance configured to focus the light signal (LU) towards at least one detonator (200).

14. Detonation system (10) according to any one of claims 12 or 13, CHARACTERIZED in that the control console (100) comprises a modulator (120) configured to modulate the light signal (LU) according to at least one modulation pattern (M).

15. Detonation system (10) according to any one of claims 12 to 14, CHARACTERIZED in that the modulated light signal (LU) comprises at least one activation sequence.

16. Detonation system (10) according to any one of claims 12 to 15, CHARACTERIZED in that the modulated light signal (LU) comprises a data sequence configured to send instructions to the detonator (200).

17. A method for activating a wireless electronic detonator (200) CHARACTERIZED in that it comprises a primary power source (230), at least one functional module (250) comprising at least one explosive initiator (256) and an energy storage element (253) dedicated to igniting the explosive initiator (256), an ignition switch (240) disposed between the primary power source (230) and the functional module (250), configured to connect or disconnect the functional module (250) and the primary power source (230), and a control module (210) for the ignition switch, the method comprising the following steps: • Reception of a light signal (LU); • Demodulation of the received light signal (LU); • Generation of a control signal, in accordance with the demodulated light signal (LU), the control signal being configured to direct at least the ignition switch (240). z / n;nn / zznz / e / YiAi 18. Activation procedure according to claim 17, CHARACTERIZED in that the light signal reception stage (LU) comprises a light signal detection stage (LU) and a light signal conversion stage (LU) into an electrical signal.

19. Activation method according to any one of claims 17 or 18, CHARACTERIZED in that the demodulation stage comprises a stage for transforming the electrical signal into a digital signal and a stage for identifying at least one activation sequence in the digital signal and, if an activation sequence is identified, the stage for generating a control signal comprises a stage for activating the ignition switch (240).

20. Activation procedure according to any one of claims 17 to 19, CHARACTERIZED in that the demodulation step comprises a 15 step of identifying at least one data sequence in the digital signal and, if a data sequence is identified, the step of generating a control signal comprises a step of generating instructions corresponding to the data sequence.

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