Leakage detection

Abstract

There is provided a sensor node arrangement for a leakage event detection comprising two or more electrode elements from which at least one includes material with a different standard reduction potential than at least other one of the two or more electrodes, and electrolyte salt material. Upon a leakage event, the electrolyte salt is configured to cause a salt-bridge over the two or more electrode elements. The salt bridge and the electrode elements are configured to form an electrochemical cell. Sensor node electronics is configured to detect the leakage event from electric power generated by the electrochemical cell.

Description

TITLELeakage detectionTECHNICAL FIELD

[0001] The present invention relates to a method and a sensor node arrangement for leakage, moisture, condensation, or flooding detection, and uses for such.BACKGROUND

[0002] Flooding, moisture, condensation, or leakage in buildings due to water plumbing leakage or various other human errors is a significant issue that can lead to various problems. Water leaks can weaken the structural integrity of a building. Water leaks can weaken the structural integrity of a building: continuous exposure to water can cause wood to rot, metal to corrode, and concrete to crack. Over time, this can lead to severe damage, compromising the safety of the building. Persistent moisture or leaks create an ideal environment for mold and mildew to thrive. These fungi can spread quickly, causing health issues such as allergies, respiratory problems, and other illnesses.

[0003] Undetected leaks can lead to significant water wastage, resulting in higher utility bills. Even small leaks can waste a substantial amount of water over time, increasing costs for building owners and occupants. Flooding from plumbing leaks can damage personal belongings, including furniture, electronics, and important documents. This can lead to costly replacements and emotional distress for the affected individuals. Water and electricity are a dangerous combination. Leaks can cause electrical short circuits, posing a risk of fire and electrocution. This is particularly concerning in buildings with extensive electrical systems. Flooding can disrupt the normal functioning of a building, whether it’s a home, office, industry, or commercial space. This can lead to temporary closures, loss of productivity, and inconvenience for occupants. In addition to mold and mildew, standing water from leaks can become a breeding ground for bacteria and pests. This can lead to various health issues, including infections and allergic reactions.

[0004] Frequent or severe water damage can complicate insurance claims. Insurers may increase premiums or even deny coverage if they determine that the damage resulted from neglect or lack of maintenance. Addressing the aftermath of flooding often involvesextensive repairs and maintenance. This includes fixing plumbing issues, repairing structural damage, and replacing damaged materials. These costs can add up quickly. Addressing leaks or flooding promptly is crucial to preventing these issues. Prior art leak detection technologies do not satisfactorily solve the problem. The systems require a continuous power supply; if a battery is used, it must be changed periodically. They are relatively costly and dependent on service. Batteries make the sensor system bulky and unsuitable for deployment in tight spaces. Materials used in batteries may be unsustainable, hazardous, and require an extensive recycling process. Batteries also pose a fire hazard in the building or equipment.SUMMARY

[0005] The aim is to provide a leakage detection arrangement that avoids at least some problems of the prior art.

[0006] The invention is defined by the features of the independent claims. Some embodiments are defined in the dependent claims.

[0007] According to a first aspect of the present invention, there is provided a sensor node arrangement for a leakage event detection comprising two or more electrode elements from which at least one includes a material with a different standard reduction potential than at least one other electrode element of the two or more electrode elements, and an electrolyte salt material. Upon a leakage event, the electrolyte salt is configured to cause a salt-bridge over the two or more electrode elements. The salt bridge and the electrode elements are configured to form an electrochemical cell. Sensor node electronics is configured to detect the leakage event from the electric power generated by the electrochemical cell.

[0008] The electrode elements may be covered with at least one of the following: porous, soluble, stretchable, and hydrophilic materials. At least one of the electrodes may be applied on / into a flexible substrate. The flexible substrate may comprise metal foil, glass fiber, conductive fabrics, plastic, wood, cotton, polymer, woven material, or cloth. The flexible substrate may comprise fabric, and the electrodes and / or at least one part of the sensor node electronics is / are woven into the fabric.

[0009] The sensor node electronics may include at least one of a power management unit (PMU), a data processing unit, a sensor interfae, a memory, and a data transmission unit. A transmission unit may transmit data via a wired or wireless transmission.

[0010] The sensor node arrangement may comprise a sensor status monitor unit may include a secondary power source configured to transfer energy to the sensor node arrangement via an antenna, an induction loop, or energy harvesting from one or more sources other than leakage. The sensor status monitoring may include obtaining information about the electrical impedance of the electrodes. The sensor status monitoring may be configured to transmit information related to the impedance of the electrodes and / or an operational condition of the sensor node arrangement.

[0011] The sensor node arrangement may be configured to harvest energy from one or various energy sources. Energy harvesting may comprise radio frequency energy, chemical energy, electrical energy, light energy, mechanical vibration energy, induction energy, heat gradient energy, a fuel cell, and carbon nanotubes.

[0012] The sensor node arrangement may comprise a loop configured to wirelessly transfer energy to power up the sensor node arrangement. This may be implemented by a secondary power source other than the leakage event. An external reader and / or an energizer device may be configured to load energy in the sensor node to monitor the status of the sensor node arrangement, or to retrieve information sensed by the sensor node electronics.

[0013] The electrodes may comprise at least one of carbon, zinc, copper, silver, and / or other conductive material. The electrodes may comprise at least one of carbon fibre, zinc wire, conductive fabric, and conductive foil. The sensor node arrangement comprises a passive and / or self-powered arrangement to detect a leakage event without the need for batteries.

[0014] According to a second aspect of the present invention, there is provided a use of the sensor node arrangement of the first aspect for a roof, wherein the roof, or a part of it, is configured to form a part of the sensor node arrangement. The part of the sensor node arrangement to may comprise an energy harvesting element, for example, an electrochemical cell.

[0015] According to a third aspect of the present invention, there is provided a use of the sensor node arrangement of the first aspect for a building, a building element, an existing system and / or structure of the building, which is / are configured to form at least part of the sensor arrangement. The later may comprise energy harvesting element or / and sensor element of the sensor node arrangement for example, an electrode.

[0016] According to the fourth aspect of the present invention, there is provided a use of the sensor node arrangement of the first aspect for building, a heating, ventilation, and air conditioning system, an aircraft, a transportation trailer, a logistics container, a sea vessel, an electricity transmission network / equipment, a water / sewer transmission infrastructure and / or a mining industry.

[0017] According to a fifth aspect of the present invention, there is provided a method comprising arranging two or more electrodes from which at least one is from a material with a different standard reduction potential than at least one other of the two or more electrodes and arranging electrolyte salt. Causing, by the electrolyte salt, a salt bridge over the two or more electrodes upon a leakage event. Forming an electrochemical cell with the salt bridge and the electrodes. Generating electric power by the electrochemical cell. Detecting the leakage event, by sensor node electronics, from the electric power generated by the electrochemical cell.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the following, the embodiments are discussed in more detail with reference to the attached drawings, of which:

[0019] Figure 1 illustrates, by way of an example, a sensor element structure design and integration with sensor node electronics, and a secondary source of energy.

[0020] Figure 2 illustrates, by way of an example, a block diagram of a leakage event monitoring sensor node.

[0021] Figure 3 illustrates, by way of an example, a method for detecting a leakage event.

[0022] Figures are presented as illustrative examples, and embodiments may not be limited solely to the illustrated parts, but modifications may be made under the scope as defined in the claims. Figures that may not fully present the claimed invention aim to provide a better understanding of the context and the related technical field. The modes of operation presented are only examples of possible operating modes. Many other operation modes may be generated.DESCRIPTION OF EMBODIMENTS

[0023] A leakage event is monitored with the aid of sensor node arrangement comprising sensor electronics for leakage monitoring. A leakage event detection is enabled in environments such as buildings. Electrolyte salt is arranged over the sensor electrodes of an electrochemical cell, which are arranged on a flexible substrate or at least partly on a building element. Power harvesting electronics is connected to said sensor electrodes of the electrochemical cell and configured to communicate via a transmission antenna. This enables the implementation of a passive, self-powered sensor node arrangement for a leakage detection. A leakage event causes a salt bridge around the sensor electrodes. The leakage event is detected by the sensor node electronics from the energy harvested by the sensor electrodes. Information on the leakage event may be sent to a receiver through a wire or wirelessly through an antenna.

[0024] Leakage, which may be called a leakage event, refers to leakage, flooding, dripping, condensation and / or moisturization. Leakage may be an unwanted presence of water or exposure to such. It may relate to unintentional escape of liquid, excess amount of water, water vapor, a slow, gradual movement / absorption of water through a structure, liquid falling in drops, vapor turning into liquid, or alike leakage event.

[0025] Electrodes of the electrochemical cell material are sensor elements of the sensor node arrangement for a leakage event detection. Sensor elements may be called electrodes, electrode elements, or sensor electrodes. The sensor elements may function as energy harvesting elements of the sensor node arrangement.

[0026] A sensor node refers to an individual node of a network of sensor nodes. The sensor node is capable of performing a leakage event detection. The sensor node may gather, process and communicate information. The sensor may gather informationchemically and convert it from an analog to a digital form. Digital information is processed by a sensor node electronics, which may comprise a processor or a controller, and a memory, for example. The processed information may be transmitted by a transceiver. In the following an antenna is part of a transceiver, but similarly communication may be implemented using infrared, optical means, like laser, or other wireless communication technologies. The sensor node may comprise one or more energy harvesting elements, sensor node electronics, and a transceiver, for example including a sensor node communication antenna.

[0027] The sensor node electronics may comprise energy harvesting electronics, a power management unit (PMU), sensor interface electronics, data processing electronics, memory, data transmission / communication radio electronics, and / or other communication interfaces for sensor node electronics configuration / testing. The sensor node electronics may comprise at least one of a PMU, a data processing unit, a sensor interface, a memory and a data transmission unit.

[0028] Figure 1 illustrates, by way of an example, a sensor structure design and integration with sensor node electronics. A top view 1001 of the sensor element is illustrated in the middle of Figure 1. The top view illustrates electrodes A and B, or sensor electrodes, which are on a flexible substrate 101. The right side of Figure 1 illustrates a side view 1002 of the same sensor element. Flexible substrate 101 is on the right side of the side view 1002. Electrode A and electrode B are printed on the flexible substrate 101. Electrode A may comprise carbon ink. Electrode B may comprise zinc. A collector 103, or a current collector, may be printed under the electrode B. An encapsulation of salt 104, which may comprise electrolyte salt, is arranged on top of the sensor electrodes A and B. The encapsulation may comprise a water-soluble envelope 105 with or without a hydrophilic substance, which may be configured to attract and form a gel upon exposure to water. This, in part, forms a salt-bridge over the surface of the sensor electrodes A and B. The encapsulation and / or substrate may be porous, flexible, and stretchable. The sensor electrodes A and B are configured to function as energy harvesters, and those are connected to the sensor node electronics 1003 on the left side of Figure 1. Via energy harvesting and with a power management unit 106, the sensor node electronics 1003 is configured to extract energy from the electrodes A and B. This enables powering the sensor node electronics 1003 without a battery or an external power source. With the provided power, communication and / or a data transmission unit 107 may transmit aleakage alert. The data transmission unit is configured to transmit data via a wired and / or wireless transmission. The leakage alert may be transmitted wirelessly via an antenna 108 of the sensor node electronics 1003. The antenna 108 may be protected by a hydrophobic layer to avoid the transmission loss in a wet environment. Energy harvesting and power management unit 106 of the sensor node electronics 1003 may be configured to harvest energy from various sources of energy. One of which is energy harvesting electrodes A, B to harvest electrochemical energy from the leakage event itself. A secondary energy source 111 may include an attachment of an induction loop to power up the sensor node with external excitation in order to monitor the status of the sensor node when a leakage event has not occurred yet. Another secondary energy source 111 example is radio frequency (RF) energy harvesting via antenna 108. Energy harvested from the secondary energy source 111 is processed and managed by PMU 106 of the sensor node electronics 1003. The secondary energy source 111 is such as the induction loop or RF energy from antenna 108, which is configured to power the sensor node for sensor status monitoring. The sensor electrodes A, B, and the overall functionality of the sensor node, may be tested / monitored using the secondary power source 111 to power the sensor node. Such testing or monitoring is implemented by using the secondary power source 111 as the primary power for the sensor node, instead of a leakage event, or when a leakage event has not yet occurred. Wireless energy transmitter using induction loop to power various such sensor nodes may be included as secondary power for status monitoring, which has been presented in more detail in a publication of IEEE Transactions on Industrial Electronics, vol 65, no. 2, pages 1358-1366, February 2018, “Analytical and Experimental Investigations of Omnidirectional Wireless Power Transfer Using a Cubic Transmitter”, by Nam H-Van, and Chulhun Seo.

[0029] The secondary power source 111 may comprise, or be part of, a secondary energy source, such as an induction loop, configured to get (harvest) energy from an external device, an energizer device, a reader device. The secondary power source enables to power the sensor node to monitor sensor node status. The secondary power source 111 is able to connect and power one or more sensor nodes at a time and to monitor status of the one or more sensor nodes.

[0030] At least one of the electrodes A, B may be applied on / into the flexible substrate. The energy harvesting (sensor) electrodes A, B may be printed on a flexible substrate with electrode A and electrode B made of carbon and zinc ink, respectively.Under electrode B, a layer of carbon ink is printed to act as a current collector. A fine powdered salt layer is encapsulated on top of the sensor electrodes. This encapsulation may be a porous, flexible, stretchable, hydrophilic layer that attracts water and dissolves in water to form a gel structure. Upon exposure to leaked water, this gel creates a salt bridge over the surface of the sensor electrodes. The printed sensor electrodes, together with the salt bridge, form an electrochemical / galvanic cell. The energy harvesting and power management electronics are configured to extract energy from these electrodes to power the sensor node electronics. This enables the sensor node electrodes to generate a leakage alert and transmit it, or information on the leakage event / alert, wirelessly. The energy harvesting may comprise utilization of radio frequency energy, chemical energy, light energy, mechanical vibration energy, induction energy, heat gradient energy, a fuel cell, a bio cell, and carbon nanotubes, optionally on polyamide.

[0031] At least one of the electrodes A, B may be applied into a flexible and / or stretchable substrate. The (sensor) electrodes A, B may be woven on / into a fabric. For example, anode, cathode, an induction loop, electrolyte material, conductive wires, and hydrophilic material may be in a fibre or thread form. A sensor node may comprise a loop configured to include, and / or connect with, a secondary energy source, which is configured to power up the sensor node electronics for status monitoring once in a while.

[0032] Two (or more) electrodes comprise material of standard reduction potential such that at least one of the two or more electrodes is of a material with a different standard reduction potential than one of the other two or more electrodes. The standard reduction potential is measured under standard conditions of temperature T = 298.15 K, a unity activity (a=l) for each ion participating in the reaction, a partial pressure of 1 atm (1.013 bar) for each gas taking part in the reaction, and metals in their pure state. The standard reduction potential is defined relative to the standard hydrogen electrode (SHE) used as a reference electrode, which is arbitrarily given a potential of 0.00 V. These may also be referred to as redox potentials. Reduction potential is a measure of the tendency of a chemical species to acquire electrons from or lose electrons to an electrode and thereby be reduced or oxidised, respectively. Redox potential is expressed in volts (V). Each species has its own intrinsic redox potential. The more positive the reduction potential, the greater the species ‘ affinity for electrons and tendency to be reduced. One of the electrodes may be a cathode, and another (of the two or more electrodes) may be an anode.

[0033] A collector 103 may be a conductive component configured to transfer current from the electrode B via the electrolyte salt bridge (formed by encapsulated salt 104). The collector 103 is configured to support the active material layer of the electrode B. The collector 103 may form an inert interface, i.e., it does not chemically react with the salt 104 or the material of electrode B. The collector 103 may comprise aluminium, copper, carbon, titanium, silver, or alike conductive material. The collector materials may have high electrical conductivity, be thin and flexible or stretchable, and be chemically stable with the electrode material and electrolyte.

[0034] Figure 2 illustrates, by way of an example, a block diagram of a leakage event monitoring sensor node. The block diagram comprises three parts: sensor elements 2001, sensor node electronics 2002, and communication unit 2003. The sensor elements2001 and / or communication antennas 2003 may be printed. The sensor node electronics2002 may comprise an application-specific integrated circuit (ASIC). The sensor elements 2001 may comprise energy harvesting electrodes 201 and electrodes 202. The sensor node electronics 2002 may comprise a controller 203 and parts for connecting and controlling other parts. Frontend interfaces 204 of the sensor node electronics 2002 are configured to connect with electrodes 202 (of the sensor elements 2001). A power management unit (PMU) 205 is configured to manage the harvested energy from harvesting electrodes 201 and / or from one or more secondary energy sources, such as an induction loop, and to reliably power the sensor node electronics 2002 for normal leakage detection or status monitoring. Wireless transceiver 206 of sensor node electronics 2002 is connected to an antenna 207, which is part of the communication unit 2003 block of the leakage monitoring sensor node. The blocks of Fig. 2 may comprise two or more energy harvesters 201, sensor elements 202, interfaces 204, controllers 203, and / or communication antennas 207. The communication antennas 207 may be used for the purpose of energy harvesting using another secondary source.

[0035] Components, such as the energy harvesting components, sensing elements, and communication antennas, may be printed on a flexible substrate. The sensor node electronics may be integrated into a chip deployed on a flexible substrate. Quality monitoring may be based on capacitance measurements between the sensor electrodes, with the option to utilize resistance measurements as well. The communication circuit is responsible for transmitting information, while the control circuit handles timing and measurement tasks.

[0036] A substrate of the sensor node is at least partly flexible. A substrate forms, at least partly, a sensor part of a sensor node arrangement. The substrate may be made rigid, at least partly, or comprise an existing structure or element. The substrate may comprise a hard area, with less or no flexibility, configured to hold sensor node electronics. The hard area may comprise small edge area, for example 2-3 cm from outer edge of the substrate, or a small comer of the substrate, for example 10 % or less compared to a total area of the substrate. The substrate may comprise flexible foil, metal foil, glass fiber, glass fiber-based material, conductive fabrics, plastic, polymer, cotton, wood, woven material, cloth or fabric. Plastic may comprise polymer, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polyimide, for example. Substrate may comprise electric material, carbon fibre, conductive wire, zinc wire, or aluminium foil, for example. Fabric may comprise a conductive batch or conductive fibers, which may optionally be woven into the fabric. Wood substrate may include a conductive wire.

[0037] The substrate may enable ink printing and is able to hold the ink. Ink may be conductive or semiconductive. Surface energy of the substrate has an effect on how well the ink spreads and sticks. Porosity of the substrate determines ink absorption. Chemical compatibility of the substrate with the ink ensures that the ink does not degrade the substrate. Both sides of the substrate may be ink printed.

[0038] Electrodes of an electrochemical cell may comprise at least one of: carbon, zinc, copper, aluminum, silver, and other conductive materials. The electrodes may comprise carbon fiber, zinc wire, or conductive foil. Each electrochemical cell comprises two electrodes, which both include electrode material, for example, zinc, carbon, copper, aluminium, silver, graphite or alike metal. The electrochemical cell converts chemical energy into electrical energy through reduction-oxidation, i.e., redox reactions, which are spontaneous. Each electrode may be made of a metal that participates in the redox reaction. A difference in electrode materials may aid in the creation of a potential difference between the electrodes.

[0039] Encapsulated salt, upon combining with water, forms an electrolyte for the electrochemical cell. The encapsulated salt may comprise an electrolyte salt, for example, sodium chloride (NaCl), potassium chloride (KC1), normal salt, or alike. Magnesium chloride may be added to the capsule of salt in order to enhance the electricity of the salt. The encapsulation may comprise an amount of salt, for example, of 100-300 mMol.However, any amount of salt may be suitable depending on the application and use of the leakage event detection. For example, an amount of around 10 mMol may be used, as well as an amount of around 500 mMol.

[0040] Encapsulated electrolyte salt may be covered or enveloped with material, which may be called an envelope. An envelope is configured to cover, or envelope, both electrodes of the electrochemical cell. An envelope is configured to hold the salt in the sensor node arrangement. The envelope may comprise porous, stretchable, and / or soluble material. The envelope may comprise hydrophilic material. Hydrophilic material is easily wetted by water and water spreads across the surface of a hydrophilic material rather than forming droplets. Hydrophilic materials may absorb or swell in humid or wet environments. Hydrophilic material may comprise cellulosic material, paper, blotting paper, absorbing paper, soft paper, structures, or alike.

[0041] The envelope is configured to attract water onto it. The leaked water, or moisture, may be spread over the surface of the envelope. Leaked water, or moisture, may be uniformly spread over the surface of the envelope. Upon a leakage event, salt is dissolved to water (or moist) and a salt bridge is formed over the electrodes. This enables chemical energy harvesting from the electrodes of the electrochemical cell.

[0042] Energy harvesting electronics enable converting harvested energy into another form. Energy harvesting provides a self-sustaining power source, eliminating the need for conventional batteries or wired connections. Chemical energy from the electrodes may be converted into electrical energy for powering the sensor node arrangement and enabling informative alerts on leakage event detection. Energy harvesting is dependent on the material used and the electrodes. An electrochemical cell converts chemical energy into electrical energy using metals and / or other materials as catalysts. A fuel cell converts chemical (fuel) energy into electrical energy using metals as catalysts. Radio frequency (RF) energy harvesting is a technology that captures RF electromagnetic waves and converts them into usable electrical energy, such as direct current (DC). An antenna receives RF signals, which are transformed from alternating current to DC. Electrical energy harvesting may comprise collecting ambient energy from sources like light, heat, vibration, and RF and converting it into usable electrical power. Induction energy harvesting may comprise capturing energy from magnetic fields. Mechanical vibration energy can also be captured using the piezoelectric principle. Light energy harvesting maycomprise capturing and converting light into usable electrical or chemical energy. Heat gradient energy harvesting utilizes a temperature difference across a device to convert thermal energy directly into electrical energy. As an example, the substrate may comprise fabric including carbon nanotubes on polyamide fibers, where the carbon nanotubes may be used as energy harvesters. Carbon nanotubes are sensitive to biomolecules and gas molecules due to their large surface area and tunable conductivity. Carbon nanotubes are printable onto flexible, as well as rigid, substrates.

[0043] Harvested energy is dependent on an area which is in contact with water. Due to this, an envelope is a hydrophilic material and electrodes of the electrochemical cell material, being sensors of the sensor node arrangement, form at least half of the area of the substrate. Electrodes may cover 50 % or more of the area of the substrate. The sensor node arrangement may comprise printed, on-chip electrodes, or weaved or fabric included electrodes. Providing electric material by printing may be costly, become brittle and deteriorate over time. Fabrics or weaved materials with carbon material or polymer fibers as electrodes, may enable providing more reliable substrate. The chemistry is the same for both electrodes on the substrate and electrodes into the substrate.

[0044] The presented leakage event monitoring and detection enables to utilize an electrochemical cell and electrolyte salt in inherently dry areas. The sensor node arrangement is applied to a transducer system, which normally should be kept dry. While previously energy has been supplied by batteries, the introduced sensor node arrangement enables harvesting energy to power the sensor node for leakage detection and creates alerts upon exposure to water / moist. This enables the provision of a passive sensor node arrangement without the need for batteries. No external power source is required for the leakage detection, but the sensor node arrangement is self-powered.

[0045] An electrochemical reaction is utilized for energy harvesting in the sensor node arrangement. This causes oxidation at the anode and reduction at the cathode, represented by electrodes of materials of different standard reduction potentials. Salt solution is used as an electrolyte to form the galvanic cell. Electrode material may be reactive, such as copper or zinc, or inert, such as graphite or platinum. Energy is provided from the galvanic cell. The leakage event causes exposure to water (or moisture), which powers the leakage detection sensor node electronics. An alert, or information on the leakage event, may be provided. It may be transmitted wirelessly via an antenna. Anexternal reading-device / receiver, or an energizer device, may be used for reading information from the sensor node arrangement. A sensor antenna (207) may also be used as a secondary source of energy, such that energy may be provided via the sensor antenna (207) in order to power up the sensor node electronics (2002) or at least part of the sensor node electronics (2002). In such a case, sensor status may be verified without a leakage event by using an external energizing device. Each sensor node (e.g., as presented in Fig. 2) may have a specific identifier (ID) which is saved in the memory of the sensor node electronics (2002). The sensor nodes may be used as a network of the sensor nodes, including number of those. An external device may wirelessly connect and power to one or multiple sensor node simultaneously to monitor the status of the one or multiple sensor nodes, respectively. In case of a leakage event, the IDs of the one or more energized / activated sensor nodes may indicate an alert with specified positions (IDs) of the leakage event. A wall-powered or battery-powered receiver (e.g., external reader and / or an energizer device) may receive and / or retrieve the leakage detection or status information from the sensor node wirelessly / with wire and process the information. Data security and sophisticated encryption techniques may be applied in the receiver to establish the system integrity. It is possible to have a processor as part of the sensor node arrangement (e.g., on the sensor node electronics, the sensor electronics or ASIC) and to process the sensor data and implement encryption techniques before transmitting an alert or informing about it. The alert relay mechanism may involve cloud data management and user interface, such as software applications, for various concerned personnel, institutions and / or systems.

[0046] Sensor node arrangements for leakage monitoring and detection may be made for end products of different forms, shapes, and sizes. For example, a roll of sensor material may be provided. This is enabled by the flexible substrate. A roll of sensor material may be useful for wide areas. For example, a roll of sensor material may be unrolled for a whole roof below an external roofing material such as bitumen sheets. The end product may cover cavities and joint parts by overlapping those, for example, under the waterproofing sheets. The end product may be stretchable, which, with flexibility, allows application to uneven surfaces. The end product may include adhesive, which makes it easy to install, since it sticks in its place. Adhesive may be applied on one surface side of the end product. The end product may be pushed around comers. The end product enables it to be cut into pieces, and / or holes to be cut into it, as long as the electric parts aremaintained uncut, in one piece. The end product is usable for multiple applications and purposes.

[0047] Material size and shape may be adapted for leakage event detection at specific places, like around metal pipes or concrete chimneys, which pass through a roof. The Specific forms and sizes may be utilized for specific places and needs. Special applications may be utilized indoors, for example, in hospitals, hotels, or other public or private places. In such places, the structure may emphasize the geometry of electrodes and the positioning of the sensor nodes in order to cover selected places at a selected sensor deployment density.

[0048] In an embodiment, a tin roof or a metal roof may be zinc-coated. The roof may form part of the energy harvesting element, such as an electrochemical cell. Similarly, a metal pillar may be used as a part of the electrochemical cell. On the roof, under an insulation layer, a thin aluminum coating may be utilized similarly as an electrode as zinc. There are a number of possibilities to make the energy harvesting mechanism part of an existing structure or system. The sensor node arrangement for leakage detection may be used for a building, a heating, ventilation and air conditioning system (HVAC), an aircraft, a transportation trailer, a logistics container, a sea vessel, an electricity, a water / sewer transmission infrastructure and / or a mining industry.

[0049] Sensor node electronics 2002 are configured to detect a leakage event from the power generated by the energy harvesting electronics 201. The sensor node electronics 2002 may include means for forwarding a signal or data regarding the detected leakage event. Data may be forwarded via a wireless transmission. Alternatively, a reader may be utilized to read a stored indication on a leakage event. Transmission and / or reading may utilize short-range connections, such as near field communication (NFC), Bluetooth, long range (LoRa), temporary antenna links, or wireless network protocols based on IEEE 802.11 (Wi-Fi) or custom communication protocols. In addition, long-range connections, such as cellular networks, satellite communication, Ethernet, or fiber connections, may be utilized. Long-range connections may be used by an external device / reader. Use of an external device, such as a reader, in the vicinity of the sensor nodes makes it possible to read the low-power sensor nodes that require less power from the sensor node arrangement.

[0050] The sensor node arrangement may comprise means for monitoring sensor status. The sensor status monitor unit enables monitoring the status and / or functionality of the sensor node arrangement and / or parts of it when a leakage event has not yet occurred. The sensor status monitoring may involve a secondary power-up mechanism (e.g., such as induction loop 111 or antenna 108 in Fig. 1) connected to the energy harvesting electronics interface or PMU. The induction loop can also be integrated into sensor element 101 in Fig. 1. The secondary power-up mechanism enables the sensor node arrangement without a leakage event, but via other energy harvesting mechanisms, such as electromagnetism, RF, light energy, or temperature gradient. The sensor node status monitoring may be configured to obtain information about the electrical impedance between the electrodes and / or an operational condition of the sensor node arrangement and sensor electronics to verify the functionality of the sensor node once in a while during the life span of the sensor node. Impedance is approximately the same for all electrode pairs. A change of impedance is an indication of a problem with electrodes. In order to monitor the sensor node arrangement, an external power source may be used to wirelessly power up the leakage detection sensor node or parts of it. For example, a sensor node network on a roof or floor may comprise tens of thousands or hundreds of thousands of sensor nodes comprising electrodes. A loop included inside electrodes may be arranged to power up the monitoring of the sensor node arrangement with secondary power. A loop may be arranged to induce magnetic energy and generate electric power as an alternative to the activation by moisture (from a detected leak). A wireless power transmitter can be used to power one or many sensor nodes for status monitoring. A loop-base can be included in the electrodes or as a separate mechanism, and such may be arranged on selected areas, such as water lines of a building or a roof. This enables loading power from a wireless energy transmitter. In addition, the antenna may be used to harvest energy from a signal, such as an RF signal, powered by an external device. The sensor status monitoring may be configured to transmit information related to the impedance of the electrodes and / or an operational condition of the sensor node arrangement.

[0051] The sensor node arrangement is disposable. The sensor node arrangement may be used in passive mode, such that it is self-energized. Passive sensor node arrangement without batteries requires less or no maintenance compared to battery- energized arrangements.

[0052] Figure 3 illustrates a method for detecting a leakage event. The method comprises arranging two or more electrodes from which at least one is from a material with a different standard reduction potential than at least one of the other two or more electrodes, at a phase 301, and arranging electrolyte salt, at a phase 302. Causing, by the electrolyte salt, a salt bridge over the two or more electrodes upon a leakage event, at a phase 304. Forming an electrochemical cell by the salt bridge and the electrodes, at a phase 305. Generating electric power by the electrochemical cell, at a phase 306. Detecting the leakage event, by sensor node electronics, from electric power generated by the electrochemical cell, at a phase 306.

[0053] In the previous description and figures presented, leakage event monitoring and detection enable avoiding a number of unwanted consequences of water leakages or flooding. Leakage events inside buildings may lead to various problems, which are avoided by the described sensor node arrangement. Rotting of wood, corroding of metal, and / or cracking of concrete may be avoided due to leakage detection. This may enable a building to maintain its condition, safety, and value. Healthy issues may be avoided by leakage detection, enabling the avoidance of fungi, mildew, mold, bacteria, and / or pests. Water wastage and costs for such may be avoided, as well as damage to personal belongings. Risk related to electricity and electrical systems may be decreased or avoided. Maintenance and protection of one's own property may be implemented and shown, for example, for insurance purposes, by a sensor node arrangement, which is not dependent on the service and maintenance of a power source.

[0054] It is to be understood that the embodiments of the invention disclosed are not limited to the particular structures, process steps, or materials disclosed herein, but are extended to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It should also be understood that the terminology employed herein is used for the purpose of describing particular embodiments only and is not intended to be limiting.

[0055] The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the previous description, numerous specific details are provided, such as examples of structures, lengths, widths, shapes, etc., to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention can be practiced without one ormore of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[0056] While the foregoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage, and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as set forth in the claims below.

[0057] The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of also un-recited features. The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of “a” or “an”, i.e. a singular form, throughout this document does not exclude a plurality.

Claims

CLAIMS:

1. A sensor node arrangement for a leakage event detection comprising- two or more electrode elements (A, B) from which at least one includes material with a different standard reduction potential than at least one of the other two or more electrode elements,- electrolyte salt (104),- wherein upon a leakage event, the electrolyte salt (104) is configured to cause a salt-bridge over the two or more electrode elements,- wherein the salt bridge and the electrode elements (A, B) are configured to form an electrochemical cell, and- sensor node electronics (1003, 2002) configured to detect the leakage event from electric power generated by the electrochemical cell.

2. A sensor node arrangement according to claim 1, wherein the electrodes (A, B) are covered with at least one of the following: porous, soluble, stretchable, and hydrophilic material.

3. A sensor node arrangement according to any one of the previous claims, wherein at least one of the electrode elements (A, B) is applied on and / or into a flexible substrate (101).

4. A sensor node arrangement according to the previous claim 3, wherein the flexible substrate (101) comprises at least one of the following: metal foil, glass fiber, conductive fabrics, plastic, wood, cotton, polymer, woven material, and cloth.

5. A sensor node arrangement according to any one of the previous claims, wherein the sensor node electronics (1003, 2002) include at least one of the following parts: a power management unit (PMU), a data processing unit, a sensor interface, a memory, and a data transmission unit.

6. A sensor node arrangement according to the previous claim 5, dependent on the claim 3 or 4, wherein the flexible substrate (101) comprises fabric, and wherein the electrode elements (A, B) and / or at least one part of the sensor node electronics (1003, 2002) is / are woven into the fabric.

7. A sensor node arrangement according to claim 5, wherein the transmission unit (206) is configured to transmit data via a wired and / or wireless transmission.

8. A sensor node arrangement according to any one of the previous claims, comprising a secondary power source (111) configured to transfer energy to the sensor node arrangement via an antenna, an induction loop, or energy harvesting from the secondary power source (111).

9. A sensor node arrangement according to the previous claim 8, wherein the sensor status monitoring is configured to obtain information about the electrical impedance of the electrodes (A, B).

10. A sensor node arrangement according to any one of the previous claims 8-9, wherein the sensor status monitoring is configured to transmit information related to the impedance of the electrodes (A, B) and / or an operational condition of the arrangement.

11. A sensor node arrangement according to any one of the previous claims, wherein the electrodes (A, B) are configured to harvest energy, and wherein energy harvesting comprises at least one of the following: radio frequency energy, chemical energy, electrical energy, light energy, mechanical vibration energy, induction energy, heat gradient energy, a fuel cell, a bio cell, and carbon nanotubes on polyamide.

12. A sensor node arrangement according to any one of the previous claims, comprising a loop configured to wirelessly transfer energy to power up the sensor node arrangement.

13. A sensor node arrangement according to any one of the previous claims, comprising an external reader and / or an energizer device, which is configured to load energy in the sensor node electronics (1003, 2002) in order to monitor the status of the arrangement, orconfigured to retrieve information sensed by the sensor node electronics (1003, 2002).

14. A sensor node arrangement according to any one of the previous claims, wherein the electrodes (A, B) comprise at least one of the following: carbon, zinc, copper, silver and / or other conductive material.

15. A sensor node arrangement according to any one of the previous claims, wherein the electrodes (A, B) comprise at least one of the following: carbon fibre, zinc wire, and conductive foil.

16. A sensor node arrangement according to any of the previous claims, comprising a passive and / or self-powered sensor node arrangement for detecting a leakage event.

17. A sensor node network comprising sensor node arrangements according to one any of claims 1-16, the sensor node network optionally comprising adhesive.

18. Use of the sensor node arrangement according to any one of claims 1-16 or the network of claim 17, for a roof, wherein the roof, or a part of it, is configured to form a part of the electrochemical cell.

19. Use of the sensor node arrangement according to any one of claims 1-16 or the network of claim 17, for a building, a building element, an existing system and / or a structure of the building, which is / are configured to form at least part of the electrode or the sensor node arrangement.

20. Use of the sensor node arrangement according to any one of claims 1-16 or the network of claim 17, for a building; a heating, ventilation, and air conditioning system; an aircraft; a transportation trailer; a logistics container; a sea vessel; an electricity; a water / sewer transmission infrastructure, and / or a mining industry.

21. A method for detecting a leakage event, comprising:arranging two or more electrode elements from which at least one includes material with a different standard reduction potential than at least one of the other two or more electrode elements (301), arranging electrolyte salt (302), causing, by the electrolyte salt, a salt-bridge over the two or more electrode elements upon a leakage event (303), forming an electrochemical cell by the salt bridge and the electrode elements (304), generating electric power by the electrochemical cell (305), and detecting the leakage event, by sensor node electronics, from electric power generated by the electrochemical cell (306).

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