A silent underwater wireless communication device and method based on contact ion current

Abstract

The present invention discloses a silent underwater wireless communication device and method based on contact ion current, the device comprising: a transmitting electrode, the transmitting electrode is grounded; a receiving electrode, the receiving electrode is grounded through an external circuit, and a current detection device is arranged on the external circuit; the transmitting electrode and the receiving electrode are made of different metal materials; a first metal sheet; a second metal sheet; the first metal sheet and the second metal sheet are made of different metal materials. The present invention uses ion current as an information carrier to realize silent communication, which greatly enhances the concealment of underwater communication.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater wireless communication, and in particular to a silent underwater wireless communication device and method based on contact ion current. Background Art

[0002] Underwater communication technology has broad application prospects in the fields of marine science, underwater exploration and national defense operations. In the past few decades, significant progress has been made in the field of underwater communication. Commonly used underwater communication methods include acoustic methods, optical methods and electromagnetic methods.

[0003] Underwater acoustic communication is still the main mode of underwater communication because it is suitable for long-distance and reliable data transmission. It has excellent robustness against noise interference from marine organisms and ship traffic, and can transmit data stably. However, the limited data rate limits its communication bandwidth. At the same time, due to its high sensitivity to attenuation and propagation delay, it is easy to cause communication delay.

[0004] Unlike underwater acoustic communication, electromagnetic underwater communication uses the characteristics of electromagnetic waves to transmit data in an underwater environment. Compared with acoustics, because water absorbs electromagnetic waves, resulting in signal attenuation, the range of electromagnetic communication in water is small and is only suitable for short-range applications, such as close-range communication between underwater sensors or robotic vehicles.

[0005] Optical underwater communication provides a promising solution for high data rate communication in underwater environments. It uses optical signals (usually blue-green spectrum) to transmit data in water. Unlike underwater acoustic communication, optical underwater communication can provide higher bandwidth and data rate at shorter distances, suitable for specific underwater applications. However, underwater optical communication still faces some challenges, including limited range due to the absorption and scattering properties of water, sensitivity to water turbidity and suspended particles, and the need for line-of-sight communication.

[0006] In addition, the above-mentioned conventional underwater communication methods require the use of hydroacoustic, electromagnetic waves or light waves as communication carriers, which are easily monitored by potential opponents. In certain specific fields, such as military, defense and intelligence operations, silent communication cannot be achieved. Summary of the invention

[0007] In view of the technical problem that the existing underwater communication technology is easily monitored, a silent underwater wireless communication device and method based on contact ion current is provided. The present invention mainly utilizes the ion currents of different sizes and directions generated when the electrode contacts different metal sheets, and realizes silent underwater communication by monitoring the ion currents.

[0008] The technical means adopted by the present invention are as follows:

[0009] In one aspect, the present invention provides a silent underwater wireless communication device based on contact ion current, comprising:

[0010] A transmitting electrode, wherein the transmitting electrode is grounded;

[0011] A receiving electrode, wherein the receiving electrode is grounded through an external circuit, and a current detection device is provided on the external circuit;

[0012] The transmitting electrode and the receiving electrode are made of different metal materials;

[0013] first metal sheet;

[0014] The second metal sheet; the first metal sheet and the second metal sheet are made of different metal materials.

[0015] Furthermore, the materials of the first metal sheet and the second metal sheet are selected to meet the following requirements:

[0016] When the transmitting electrode contacts the first metal sheet underwater, a first current pulse is generated on the external circuit. When the transmitting electrode contacts the second metal sheet underwater, a second metal pulse is generated on the external circuit. The first current pulse is different from the second current pulse.

[0017] Furthermore, the first current pulse and the second current pulse have different directions.

[0018] Furthermore, the first current pulse and the second current pulse have the same direction but different current magnitudes.

[0019] Furthermore, the transmitting electrode is a copper electrode, and the receiving electrode is a platinum electrode;

[0020] The first metal sheet is made of gold or platinum, and the second metal sheet is made of one of aluminum, zinc and iron.

[0021] Furthermore, the transmitting electrode is a copper electrode, and the receiving electrode is a platinum electrode;

[0022] The first metal sheet is made of gold, and the second metal sheet is made of platinum.

[0023] Furthermore, the transmitting electrode is a copper electrode, and the receiving electrode is a platinum electrode;

[0024] The material of the first metal sheet and the second metal sheet is a combination of any two of aluminum, zinc and iron.

[0025] On the other hand, the present invention also provides a silent underwater wireless communication method based on contact ion current, which is implemented by the above-mentioned silent underwater wireless communication device based on contact ion current, and includes the following steps:

[0026] S1, immersing the receiving electrode, the first metal sheet and the second metal sheet into liquid;

[0027] S2, immersing the transmitting electrode in water, and keeping the transmitting electrode, the receiving electrode, the first metal sheet and the second metal sheet not in contact with each other;

[0028] S3, the communication process starts, and the transmitting electrode is respectively contacted with the first metal sheet or the second metal sheet according to the communication content, when the transmitting electrode is in contact with the first metal sheet, a first current pulse is generated in the external circuit, and when the transmitting electrode is in contact with the second metal sheet, a second current pulse is generated in the external circuit;

[0029] S4. Monitor the first current pulse and the second current pulse in the external circuit to identify the communication content.

[0030] Furthermore, the first current pulse and the second current pulse represent a “dash” and a “dot” in Morse code, respectively.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] 1) The present invention provides a self-powered electrical signal generating and transmitting device for underwater wireless communication, which can effectively solve the problem of self-power supply during underwater wireless communication.

[0033] 2) The present invention uses ionic current as a signal carrier for communication, thereby obtaining a silent signal generation method that is not easily discovered and has great significance in military and other applications requiring secret communications.

[0034] 3) The present invention can directly display the electrical signals collected by the receiving electrodes through software after differential amplification processing without the need for complicated programs and codes.

[0035] 4) The device of the present invention is extremely light and can be operated by one person with one hand, which is convenient for divers or soldiers to carry with them. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0037] Figure 1 Schematic diagram of the contact potential difference generation process. a represents the work function state of the two metals in the isolated state; b represents the work function state of the two metals in the non-isolated state.

[0038] Figure 2Schematic diagram of the ion current generation process of the present invention.

[0039] Figure 3 It is an equivalent schematic circuit diagram of the silent communication method of the present invention.

[0040] Figure 4 Schematic diagram of silent communication method in the embodiment. Among them, a represents the expression of letters in Morse code; b gives the expression of "long dash" and "dot" in Morse code; c represents the current pulse waveform when the communication content is "SOS"; d represents the current pulse waveform when the communication content is "UP"; e represents the current pulse waveform displayed by the software when the communication content is "SOS"; f represents the current pulse waveform displayed by the software when the communication content is "UP". DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0043] On the one hand, the present invention provides a silent underwater wireless communication device based on contact ion current, comprising: a transmitting electrode, a receiving electrode, a first metal sheet and a second metal sheet. The transmitting electrode and the receiving electrode are made of different metal materials; the first metal sheet and the second metal sheet are made of different metal materials. The transmitting electrode is grounded, and the receiving electrode is grounded through an external circuit, and a device for measuring and displaying current is provided on the external circuit.

[0044] The present application proposes a silent underwater wireless communication device that realizes silent underwater wireless communication through contact-induced ion current. When the transmitting electrode contacts the metal sheet underwater, a contact potential difference is generated due to the transfer of electrons on their interface. The potential difference between the transmitting electrode and the receiving electrode is used to polarize the water and generate an ion current. The ion current signal is transmitted in the water by a non-Faraday process and is received by a receiving electrode connected to an external circuit. By configuring a signal modulation and demodulation circuit, silent underwater Morse code communication is realized.

[0045] During use of the device of the present application, the receiving electrode and the metal sheet to be contacted are first immersed in the liquid, and then the transmitting electrode is inserted into the water, at this time, the transmitting electrode, the receiving electrode and the metal sheet are kept non-contacting with each other, and when different pulse signals need to be generated, the transmitting electrode is contacted with different metal sheets respectively. Due to the different work functions of different metals, the contact potential difference generated by the contact between the two metals is different, thus generating ion currents of different magnitudes and directions.

[0046] In a preferred embodiment of the present application, different current signals are used to generate different Morse codes for communication. For example, when a copper transmitting electrode is placed in water from the air and contacts a gold sheet, a current signal collected by an external circuit during the process of a platinum receiving electrode being placed in water. When the transmitting electrode is inserted into the water without contacting the gold sheet, the magnitude of the current received by the external circuit is a negative peak value of about -1.0 μA. Then, the current signal decays to about -0.4 μA and serves as the baseline for the current pulse generated by the contact between the transmitting electrode and the gold sheet in the next stage. Since the electrode potential of copper (transmitting electrode) is lower than the electrode potential of platinum (receiving electrode), a negative potential difference is generated on the surface of the transmitting electrode. Therefore, the anions and cations in the water migrate to the surfaces of the transmitting electrode and the receiving electrode, respectively, and charge the double electric layer on the electrode surface, respectively.

[0047] When the copper transmitting electrode contacts the gold sheet, a large negative current pulse will be generated (referred to as Au current in this application, and the definitions of other currents generated by contacting different metal sheets are similar). The magnitude of the Au current is about -2.5μA, which is significantly larger than the current generated when the copper transmitting electrode is inserted into the water. The copper transmitting electrode is then removed from the gold sheet and placed in the water. Therefore, the current signal returns to the level of the first stage. Since the work function of the gold transmitting electrode (ФAu, 5.1-5.47eV) is greater than the work function of the copper transmitting electrode (ФCu, 4.53-5.1eV), the contact potential difference generated causes the negative potential on the transmitting electrode to be greater than the negative potential on the receiving electrode, thus generating a large negative current signal.

[0048] For the rest of the metals, the typical current signals of different metals are different in direction and amplitude. Among them, the current pulses generated by gold, platinum, and copper are downward, and the current pulses generated by aluminum, iron, and zinc are upward. The magnitude of the generated current pulses is also different. For example, the current magnitude of gold is about -2.5μA, the current magnitude of platinum is about -11.6μA, and the current magnitude of aluminum is about 6.2μA. Among them, the current pulse of zinc is the largest (19.7μA), and the current pulse of iron is the smallest (1.0μA). All current pulses detected in the system are proportional to the corresponding contact potential difference, which in turn causes different potential differences between the transmitting electrode and the receiving electrode.

[0049] Based on the above principles, different metal sheets can be used to generate different current pulses for communication. In an optional embodiment, the principle of selecting metal sheets is that the two metal sheets have different current pulse directions, and there is no requirement for the current size. In another optional embodiment, the two metal sheets have the same current pulse direction, but the current sizes are different, and the difference is large. In this embodiment, the positive current pulse is defined as a "long dash" in Morse code, and the negative current pulse is defined as a "dot" in Morse code. According to the positive and negative current pulses generated by the contact between the transmitting electrode and the metal sheet, the expression of different English letters in Morse code can be realized.

[0050] On the other hand, the present invention also provides a silent underwater wireless communication method based on contact ion current, which is implemented by the above-mentioned silent underwater wireless communication device based on contact ion current, and includes the following steps:

[0051] S1, immersing the receiving electrode, the first metal sheet and the second metal sheet into liquid;

[0052] S2, immersing the transmitting electrode in water, and keeping the transmitting electrode, the receiving electrode, the first metal sheet and the second metal sheet not in contact with each other;

[0053] S3, the communication process starts, and the transmitting electrode is respectively contacted with the first metal sheet or the second metal sheet according to the communication content, when the transmitting electrode is in contact with the first metal sheet, a first current pulse is generated in the external circuit, and when the transmitting electrode is in contact with the second metal sheet, a second current pulse is generated in the external circuit;

[0054] S4. Monitor the first current pulse and the second current pulse in the external circuit to identify the communication content.

[0055] Furthermore, the first current pulse and the second current pulse represent a “dash” and a “dot” in Morse code, respectively.

[0056] The solution of the present application is further described below in conjunction with the application examples given in the accompanying drawings.

[0057] like Figure 1 As shown in Figure 1, the mechanism of contact-induced ion current includes two parts: generation and transmission. Before explaining the mechanism of ion current transmission, we first focus on the generation of ion current. Figure 1 The mechanism of contact-induced ionic current generation is shown. When two metals are electrically isolated from each other ( Figure 1 a), they are electrically neutral and have different work functions Φ, but share the same local vacuum level (E vac , at the surface of the material, electrons are prevented from escaping into the vacuum by an energy barrier that peaks at the vacuum layer). Once the two metals are in electrical contact, electrons will transfer from the metal with the lower work function to the metal with the higher work function until the Fermi levels E in the two metals are equal. F (Ф=E vac -E F ) are equal, resulting in a net charge difference at the interface of the two metals, such as Figure 1 b. Although the charge distribution on the metal surface is not the same, each metal has the same potential on its own surface. In the equilibrium state, the contact potential difference between the two is V CPD is equal to the difference in work functions of the two metals:

[0058] V CPD =ΔФ=(Ф1-Ф2) / e (1)

[0059] Where Φ1 and Φ2 are the work functions of the two metals, respectively, and e is the elementary charge. The different work functions of the contacting metals result in different contact potential differences between the metals and the transmitting electrode. Therefore, the relative potential on the transmitting electrode changes on the receiving electrode as it contacts different metals.

[0060] like Figure 2 As shown in Figure 1, in terms of ion current generation, the formation of the electric double layer (EDL) and double layer capacitance is first introduced. At a given potential, there are charges (electrons) Q on the electrodes. M , the liquid side has a charge (ion) Q S Whether the charge on the metal is positive or negative relative to the liquid depends on the potential at the interface and the composition of the liquid, but the quantity Q M Always equal to Q S The charge Q on the electrode M Indicates the excess or deficiency of electrons on the electrode, while the liquid Q S The charge in the electrolyte consists of cations or anions near the electrode surface. As a result, an electrical double layer (EDL) and a double-layer capacitor are formed at the metal-liquid interface.

[0061] The whole process of ion current generation includes two stages, namely, the electrode is immersed in liquid (stage I) and in contact with metal (stage II). In stage I, both the transmitting electrode and the receiving electrode are inserted into the water without contacting the metal. For two immersed electrodes of different materials, the transmitting electrode potential (V tr ) and the receiving electrode potential (V re ) is different, resulting in an electrode potential difference ΔV (ΔV = V re -V tr ). Therefore, the liquid (dielectric) is polarized under the potential difference ΔV. In terms of ion current transport, the moving ions Q S The double layer capacitor on the electrode surface is charged until Q S Satisfying equation Q S =C d ΔV. Therefore, for electrical neutralization, the electrons on the electrode surface will accumulate or evacuate, and the current detected in the external circuit is induced by the ion current transport in water.

[0062] Figure 2 In the case shown, if the electrode potential of the transmitting electrode is lower than that of the receiving electrode, the relative potential at the transmitting electrode is negative. Therefore, the mobile anions and cations will migrate to the surfaces of the transmitting electrode and the receiving electrode, respectively, and charge the double-layer capacitor, causing the electrons in the external circuit to migrate from the transmitting electrode to the receiving electrode until the double-layer capacitor is fully charged. Therefore, under the action of the electrode potential difference, a transient current I1 will be generated in the external circuit during the charging process. It should be noted that the detected current is not a Faradaic current (capacitive current), and it will decay to a stable value when the double-layer capacitor is fully charged. At this time, the potential difference ΔV will be mostly offset by the shielding effect of the fully charged double-layer capacitor on the surface of the transmitting electrode and the receiving electrode.

[0063] In stage II, when the emitter electrode contacts a metal sheet with a higher work function, there is a contact potential difference between the emitter electrode and the metal. The initially positively charged emitter electrode will be more positively charged (in other words, the electrons on the surface of the emitter electrode are more scarce). If we take the receiving electrode as the reference potential, the emitter electrode with more electron deficiency is relatively negative, resulting in a more negative potential at the emitter electrode. Therefore, more anions and cations will be attracted to the surfaces of the emitter electrode and the receiving electrode, respectively. Then more electrons migrate from the emitter electrode to the receiving electrode, resulting in a larger negative current I2. Similarly, when the emitter electrode contacts a metal sheet with a lower work function, the potential on the emitter electrode will be higher than the potential on the receiving electrode. Electrons in the external circuit will migrate from the receiving electrode to the emitter electrode through the electrometer, generating a positive current pulse.

[0064] like Figure 3The equivalent circuit for the generation and transmission of ion current in this embodiment is given. In the non-Faraday process, no electrons pass through the metal-liquid interface. Instead, they just flow between the transmitting electrode, the metal sheet, and the receiving electrode in the external circuit. Therefore, the current generated has nothing to do with the electrochemical reaction. The above process is similar to a s and capacitor C d RC circuit, in which the contact and separation process between the metal sheet and the transmitting electrode is equivalent to a series voltage source with a switch (red dashed box). In the equivalent RC circuit, the potential of the receiving electrode is regarded as the reference potential. Then, the potential change of the transmitting electrode depends on the contact potential difference, resulting in the potential change between the transmitting electrode and the receiving electrode. The resistance of water (R s ) and the voltage across the double layer capacitor V R and V C The sum should be equal to the contact potential difference:

[0065]

[0066] Since the current can be expressed as i = dQ s / dt, so formula (2) is rewritten as:

[0067]

[0068] Integrate formula (3), then:

[0069]

[0070] It can be seen that after the contact potential difference occurs, the charge on the emitting electrode increases exponentially. Combining equations (3) and (4), the current i can be obtained:

[0071]

[0072] From formula (5), we can see that the magnitude of the receiving current increases with V CPD It increases with the increase of , and decreases with the increase of liquid resistance. It should also be noted that the current decays exponentially with the time constant τ, defined as τ = R s C d Therefore, when V CPD When the external circuit has the maximum current i at the beginning max =V CPD / R s .

[0073] like Figure 4 As shown, this is an effective underwater silent communication method given in this embodiment. Based on the contact-induced ion current system and Morse code ( Figure 4a), the present invention proposes a wireless self-powered underwater silent communication method, which can silently translate the current signal into understandable letters through a modulation decoder under underwater conditions. In this embodiment, the transmitting electrode is a copper electrode and the receiving electrode is a platinum electrode. The material of the first metal sheet is platinum, and the material of the second metal sheet is aluminum. Figure 4 As shown in Figure 2b, Morse code is represented by different combinations of "dots" and "long dashes". Therefore, we define the positive current pulse generated by contacting aluminum as a "long dash" and the negative current pulse generated by contacting platinum as a "dot". The aluminum sheet, platinum sheet, and transmitting electrode can be fixed on the fingers respectively, and the communication can be achieved by touching the aluminum sheet or platinum sheet with a single finger. Therefore, different current signals can be generated by only three fingers on one hand to achieve silent underwater communication. Information such as "SOS" and "UP" can be represented by touching the aluminum sheet or platinum sheet representing "long dash" or "dot" in an appropriate order ( Figure 4 c-4f) and are displayed on the decoder screen respectively. Other messages, such as "GO" and "HELP", can also be conveyed underwater by simply touching two fingers. Therefore, instant silent communication can be achieved between underwater vehicles or divers.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A silent underwater wireless communication device based on contact ion current, characterized in that: include: A transmitting electrode, wherein the transmitting electrode is grounded; A receiving electrode, the receiving electrode is grounded through an external circuit, and a current detection device is provided on the external circuit, and the electrical signal collected by the receiving electrode is directly displayed through software after differential amplification processing; The transmitting electrode and the receiving electrode are made of different metal materials; first metal sheet; A second metal sheet; the first metal sheet and the second metal sheet are made of different metal materials; The materials of the first metal sheet and the second metal sheet are selected to meet the following requirements: When the transmitting electrode contacts the first metal sheet underwater, a first current pulse is generated on the external circuit. When the transmitting electrode contacts the second metal sheet underwater, a second current pulse is generated on the external circuit. The first current pulse is different from the second current pulse.

2. A silent underwater wireless communication device based on contact ion current according to claim 1, characterized in that: The first current pulse and the second current pulse have different directions.

3. A silent underwater wireless communication device based on contact ion current according to claim 1, characterized in that: The first current pulse and the second current pulse have the same direction but different current magnitudes.

4. A silent underwater wireless communication device based on contact ion current according to claim 2, characterized in that: The transmitting electrode is a copper electrode, and the receiving electrode is a platinum electrode; The first metal sheet is made of gold or platinum, and the second metal sheet is made of one of aluminum, zinc and iron.

5. A silent underwater wireless communication device based on contact ion current according to claim 2, characterized in that: The transmitting electrode is a copper electrode, and the receiving electrode is a platinum electrode; The first metal sheet is made of gold, and the second metal sheet is made of platinum.

6. A silent underwater wireless communication device based on contact ion current according to claim 2, characterized in that: The transmitting electrode is a copper electrode, and the receiving electrode is a platinum electrode; The material of the first metal sheet and the second metal sheet is a combination of any two of aluminum, zinc and iron.

7. A silent underwater wireless communication method based on contact ion current, implemented by a silent underwater wireless communication device based on contact ion current as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1, immersing the receiving electrode, the first metal sheet and the second metal sheet into liquid; S2, immersing the transmitting electrode in water, and keeping the transmitting electrode, the receiving electrode, the first metal sheet and the second metal sheet not in contact with each other; S3, the communication process starts, and the transmitting electrode is respectively contacted with the first metal sheet or the second metal sheet according to the communication content, when the transmitting electrode is in contact with the first metal sheet, a first current pulse is generated in the external circuit, and when the transmitting electrode is in contact with the second metal sheet, a second current pulse is generated in the external circuit; S4. Monitor the first current pulse and the second current pulse in the external circuit to identify the communication content.

8. A silent underwater wireless communication method based on contact ion current according to claim 7, characterized in that: The first current pulse and the second current pulse represent a “dash” and a “dot” in Morse code, respectively.

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