Silver selenide thin film electronic skin with multiple sensing functions based on thermoelectric effect and preparation method of silver selenide thin film electronic skin

Abstract

The invention provides a multi-sensing function based on a flexible thermoelectric silver selenide film, and the sensing function of natural skin is copied by utilizing a Seebeck effect. The E-skin can realize the capabilities of temperature perception, tactile perception, non-contact perception, substance recognition and the like by analyzing the heat conduction behaviors of various materials. In order to further verify the capability of the constructed E-skin, a wearable device is manufactured, the wearable device has multi-channel sensing, and gesture recognition is tested. This study highlights the potential for use of flexible thermoelectric materials in advanced biomedical applications, including health monitoring and smart prostheses.

Description

Technical Field

[0001] The present invention relates to a silver selenide thin film electronic skin with multiple sensing functions based on the thermoelectric effect and a preparation method thereof, belonging to the field of flexible sensing technology. Background Art

[0002] As the largest organ in the human body, the skin perceives external stimuli through a variety of sensory organs and plays a key role in our interaction with the environment. Skin injuries are common in daily life. Severe skin injuries or amputations can cause patients to lose their sense of touch, seriously affecting their quality of life. To simulate the perceptual capabilities of human skin, electronic skin has emerged. It can convert a variety of physical stimuli (such as pressure, vibration, heat, and strain) into electrical signals, providing a promising platform for realizing biomimetic touch.

[0003] The ability of the human body's tactile receptors to sense and understand temperature stimuli plays an important role in reconstructing physiological perception. Thermal sensors can not only detect temperature but also obtain information about physical activities and environmental conditions by analyzing various thermal interactions. However, while electronic skin has made significant progress in achieving biomimetic tactile sensations based on technologies such as piezoelectric, capacitive, piezoresistive, and electrostatic sensing, relatively little research has been conducted on the thermal sensing capabilities of electronic skin. Since previous research has mainly focused on temperature sensing applications using temperature-dependent resistors, endowing electronic skin with accurate thermal perception capabilities is of great significance for promoting its application in fields such as healthcare, robotics, and environmental monitoring.

[0004] In summary, relevant technologies are unable to utilize and analyze the information transmitted by the heat exchange that occurs when the electronic skin comes into contact with the object; the electronic skin still needs to be driven by an external power supply; the electronic skin still lacks flexibility; and it is unable to identify the type of surface material of the object during the contact process; therefore, further research is still needed. Summary of the Invention

[0005] The present invention provides a silver selenide thin film electronic skin with multiple sensing functions based on the thermoelectric effect and a preparation method thereof, so as to solve the technical problem that the related art cannot simultaneously identify the temperature, humidity and material type of the object surface through a single tactile sensor, and cannot simultaneously identify airflow, infrared light and non-contact objects through a single tactile sensor, thereby further solving the technical problem that the related art cannot sense external stimuli through information transmitted by heat exchange occurring during contact.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] A method for preparing a silver selenide thin film electronic skin with multiple sensing functions based on the thermoelectric effect, the method comprising the following steps:

[0008] S1) Preparation of sodium sulfide-selenium solution: The sodium sulfide-selenium solution was prepared by dissolving 0.6 g of sodium sulfide nonahydrate in 20 ml of double-distilled water. After complete dissolution, 0.2 g of selenium powder was added and stirred until the solution changed from colorless to deep red.

[0009] S2) Synthesis of Silver Selenide: Silver nanoparticles were sputtered onto a polyethylene film substrate in an ion sputtering apparatus, and then reacted with a sodium sulfide-selenium solution to synthesize silver selenide. The ion sputtering apparatus was operated at the following parameters for preparing a single sample: current 20 mA, pressure 4 Pa, and time 1000 s. The synthesized silver selenide had a thickness of 100 nm.

[0010] S3) Sputtering the Silver Electrode: In an ion sputtering instrument, a 3D-printed mold was used to cover the silver selenide portion, leaving the area to be sputtered exposed. The silver electrode was then sputtered. The silver nanoparticle target used in the ion sputtering instrument had a diameter of 50 mm and a purity of 99.99%. During sputtering, the instrument operated at a current of 20 mA, a pressure of 4 Pa, and a duration of 1000 seconds. Finally, the device was covered with a polyethylene film as a protective layer.

[0011] The present application provides a silver selenide thin film electronic skin with multiple sensing functions based on the thermoelectric effect and a preparation method thereof. The structure of the electronic skin comprises a sensing layer (1), wherein the sensing layer comprises a silver selenide thin film (11) and a reference silver electrode (12) and a sensing silver electrode (13) at both ends to form the sensing layer; and a synthetic region of the sensing layer forms a base layer (2) on a polyethylene film, and a polyethylene film covering the sensing layer forms a protective layer (3). The sensing layer is used to sense external environmental stimuli, the base layer is used to provide support for the sensing layer, and the protective layer is used to provide protection for the sensing layer.

[0012] Optionally, in one embodiment of the present application, the material of the substrate includes one or more of polydimethylsiloxane, polyethylene, polypropylene, polyvinylidene fluoride, perfluoroethylene propylene, vinylidene chloride acrylonitrile copolymer, polytetrafluoroethylene, polyvinyl chloride, polychlorotrifluoroethylene, polychloroprene, polyisobutylene, polyoxymethylene, polyamide, polyimide, melamine formaldehyde, polycarbonate, polyethylene glycol succinate, phenolic resin, aniline formaldehyde resin, chloroprene rubber, natural rubber, cellulose, ethyl cellulose, cellulose acetate, polyethylene adipate, polydiallyl phthalate, polyethanol butyral, styrene propylene copolymer, styrene butadiene copolymer, polyethylene glycol carbonate, polystyrene, polymethacrylate, polyester and polyurethane.

[0013] Optionally, in one embodiment of the present application, the materials of the sensing electrode and the reference electrode include one or more of gold, silver, platinum, palladium, aluminum, nickel, copper, titanium, chromium, selenium, iron, manganese, molybdenum, tungsten or vanadium, aluminum alloys, titanium alloys, magnesium alloys, beryllium alloys, copper alloys, zinc alloys, manganese alloys, nickel alloys, lead alloys, tin alloys, cadmium alloys, bismuth alloys, indium alloys, gallium alloys, tungsten alloys, molybdenum alloys, niobium alloys, tantalum alloys, graphite and conductive glass.

[0014] Optionally, in one embodiment of the present application, the material of the thermoelectric sensing layer includes inorganic thermoelectric materials such as silver selenide, silicon-germanium alloy, bismuth-antimony alloy, bismuth selenide, bismuth telluride, cadmium selenide, bismuth-antimony selenide, germanium-tin alloy, copper-indium-selenide, indium-antimonide, bismuth-indium-selenide, and bismuth telluride; and also includes organic thermoelectric materials such as polyethylene dioxythiophene-polystyrene sulfonate, polyaniline, polytriphenylamine, polyparaphenylenediamine, polythiophene, polyfluorene, polystyrene, polyacetylene, polypropyne, polymer fiber, and graphene; and also includes hydrogel thermoelectric materials such as lithium-ion thermoelectric hydrogel, bismuth-ion thermoelectric hydrogel, sodium-ion thermoelectric hydrogel, manganese-ion thermoelectric hydrogel, vanadium-ion thermoelectric hydrogel, copper-ion thermoelectric hydrogel, iron-ion thermoelectric hydrogel, titanium-ion thermoelectric hydrogel, nickel-ion thermoelectric hydrogel, and iron-lithium-ion thermoelectric hydrogel.

[0015] Optionally, in one embodiment of the present application, the material of the protective layer includes one or more of polydimethylsiloxane, polyethylene, polypropylene, polyvinylidene fluoride, perfluoroethylene propylene, vinylidene chloride acrylonitrile copolymer, polytetrafluoroethylene, polyvinyl chloride, polychlorotrifluoroethylene, polychloroprene, polyisobutylene, polyformaldehyde, polyamide, polyimide, melamine formaldehyde, polycarbonate, polyethylene glycol succinate, phenolic resin, aniline formaldehyde resin, chloroprene rubber, natural rubber, cellulose, ethyl cellulose, cellulose acetate, polyethylene adipate, polydiallyl phthalate, polyethanol butyral, styrene propylene copolymer, styrene butadiene copolymer, polyethylene glycol carbonate, polystyrene, polymethacrylate, polyester and polyurethane. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0017] Figure 1 Schematic diagram of the electronic skin architecture based on silver selenide thermoelectric thin film technology: a) Schematic diagram of the sensing system in natural skin; b) Schematic diagram of the electronic skin layered architecture; c) The electronic skin sensing mechanism. dh) The electronic skin fabrication process based on sputtering and selenization reactions. i) A photograph of a flexible silver selenide film and a wearable device integrating multiple electronic skin arrays.

[0018] Figure 2These are the characterization results of the silver selenide film prepared on the PE substrate: where a is the XRD pattern of the silver selenide film; b is the XPS spectrum of silver selenide; c is the SEM image of the silver selenide film on the polyethylene substrate; d is a high-angle dark-field scanning transmission electron microscope (STEM) cross-sectional image of the silver selenide film prepared using FIB on the polyethylene substrate; e is the composition distribution of silver and selenium elements in the silver selenide film; f is a cross-sectional high-resolution transmission electron microscope (HRTEM) image of the silver selenide film on the polyethylene substrate, showing the interface between silver selenide and polyethylene.

[0019] Figure 3 The test results of silver selenide films with different thicknesses: a shows the temperature-dependent Seebeck coefficient S of silver selenide films; b shows the Seebeck coefficient S of silver selenide films with different thicknesses at room temperature; c evaluates the carrier concentration n by Hall test H , mobility μ H and conductivity σ; d shows the curve of the power factor PF of the silver selenide film changing with thickness; e compares the power factor PF of different silver selenide films at 300K; f shows the Seebeck coefficient S of the silver selenide film before and after bending at different folding angles; g presents a schematic diagram of the flexibility test using 3D printing equipment; h shows the change of the Seebeck coefficient S of the silver selenide film with the number of bending cycles; the condition of a bending radius of 4mm was used, and the results showed that the silver selenide film with a thickness of 100nm has excellent flexibility.

[0020] Figure 4 The following is an explanation of the functions of silver selenide thin film electronic skin. a is a schematic diagram of the main functions of the electronic skin. b shows the voltage response of the electronic skin when it comes into contact with objects of different temperatures, along with optical images and temperature distribution measured using infrared thermal imaging. c shows the voltage response of the electronic skin when it comes into contact with dry surfaces of different temperatures. d shows the voltage response of the electronic skin when it comes into contact with wet surfaces of different temperatures. e shows the voltage response of the electronic skin when it is exposed to hot and cold air streams. f shows the voltage response of the electronic skin when it senses objects at different distances in a contactless manner. g shows the voltage response of the electronic skin when it is exposed to infrared light. h is a schematic diagram of the electronic skin used for material identification. i shows digital photos of various materials used for electronic skin material identification. j shows the voltage response of the electronic skin when it comes into contact with different materials. k and l show the correspondence between the maximum voltage of the electronic skin when it comes into contact with different materials and the thermal properties of the materials. DETAILED DESCRIPTION

[0021] The following describes in detail embodiments of the present application, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0022] Example 1 Synthesis and Identification of Silver Selenide Thin Film Electronic Skin of the Present Invention

[0023] S1. Synthesis of Silver Selenide Thin Film: A polyethylene film (100 μm thick) that had been ultrasonically cleaned and soaked in alcohol was placed in an ion sputtering apparatus for sputtering. The silver target in the ion sputtering apparatus had a diameter of 50 mm and a purity of 99.99%. During sputtering, the ion sputtering apparatus operated at a current of 20 mA, a pressure of 4 Pa, and a duration of 1000 seconds. The shape of the silver selenide film was controlled by a 3D-printed mask. After the silver nanofilm was synthesized, it was reacted with a pre-prepared sodium sulfide-selenium solution for 30 seconds. The solution was prepared by dissolving 0.6 g of sodium sulfide nonahydrate in 20 ml of double-distilled water. After complete dissolution, 0.2 g of selenium powder was added and stirred until the solution turned from colorless to deep red. After 30 seconds, the silver nanofilm turned from white to a gray-blue silver selenide nanofilm. The film was then rinsed with double-distilled water, rinsed thoroughly, and dried at room temperature. This resulted in a silver selenide thin film.

[0024] S2. Preparation of silver selenide electronic skin In an ion sputtering instrument, a 3D printed mold is used to cover the silver selenide part, exposing the electrode area to be sputtered, and the silver electrode is sputtered. The silver target equipped in the ion sputtering instrument has a diameter of 50mm and a purity of 99.99%. During sputtering, the working current of the ion sputtering instrument is 20mA, the working pressure is 4Pa, and the working time is 1000s. Finally, a polyethylene film is covered on the film for protection. The silver selenide film electronic skin is completed. In this design, the silver selenide layer acts as a sensing layer, converting environmental stimuli into readable signals. When thermal stimulation is applied to the sensing area, a voltage is generated, resulting in a temperature difference between the external object and the body temperature, so that relevant information about the stimulated object can be obtained. The polyethylene film covers the silver selenide film, which plays a role of protection and isolation, and can effectively prevent external factors such as humidity, gas and mechanical interference with the system. The schematic diagram of the synthesis of silver selenide film and the construction process of silver selenide electronic skin is shown in the figure. Figure 1 shown.

[0025] S3. Characterization of silver selenide thin film electronic skin and characterization results In order to confirm the phase structure of the silver selenide film obtained on the PE substrate, we performed a typical X-ray diffraction (XRD) analysis on the prepared silver selenide. The XRD spectrum confirmed that the diffraction of all films can be well indexed as β-silver selenide, referring to the silver selenide standard PDF card, and no diffraction peak of the Ag element was detected (PDF number 24-1041). This confirms that the obtained silver selenide film is pure and has a polycrystalline nature, among which the strong (002) diffraction peak is beneficial to the thermoelectric performance ( Figure 2 a).

[0026] In order to further characterize the chemical properties of the obtained silver selenide film, we used X-ray photoelectron spectroscopy (XPS) to measure the overall XPS spectrum and the corresponding high-resolution XPS spectrum of the silver selenide sample, showing that the Ag 3d 3 / 2 、Ag 3d 5 / 2 、Se3d 3 / 2 and Se 3d 5 / 2 peak, confirming that the obtained film is pure silver selenide ( Figure 2 b).

[0027] In order to show the morphology of the synthesized silver selenide film, we used scanning electron microscopy (SEM) to study it. The top and side SEM images of the silver selenide / PE film showed that under the condition of precise control of the thickness of the Ag film, silver selenide films of different thicknesses can be obtained after the selenization reaction ( Figure 2 c).

[0028] In order to further study the structural characteristics of the silver selenide film and the PE substrate below, we used transmission electron microscopy (TEM) to observe the cross section of a typical silver selenide film ( Figure 2 d), the results showed that it has a polycrystalline morphology.

[0029] Elemental mapping results further confirmed the uniform distribution of Ag and Se elements, and no impurities were observed ( Figure 2 e).

[0030] High-resolution transmission electron microscopy (HRTEM) observations show that silver selenide and PE substrate can form a strong interface, which is beneficial to the flexibility of the silver selenide film ( Figure 2 f).

[0031] Example 2 Tests on the thermoelectric and mechanical properties of the silver selenide thin film electronic skin of the present invention

[0032] 1. Thermoelectric performance test

[0033] In order to evaluate the thermoelectric performance of silver selenide films prepared on polyethylene substrates, we measured several key thermoelectric parameters of silver selenide films with different thicknesses (100nm to 500nm), including the Seebeck coefficient S, conductivity σ, carrier concentration n H and carrier mobility μ H etc. (such as Figure 3 ac). Figure 3 As shown in a and b, the Seebeck voltage of the film stabilizes at about 110 μV K at around 295 K. -1 By calculating PF=S 2 The power factor (PF) values ​​of silver selenide films with different thicknesses at 300K were obtained (e.g. Figure 3 d).

[0034] 2. Mechanical properties test

[0035] In order to evaluate the flexibility of the obtained film, we conducted bending tests at different angles. The results showed that the Seebeck coefficient S of the film remained very stable at different bending angles, such as Figure 3 As shown in f.

[0036] In addition, we also conducted repeated bending experiments on silver selenide with different thicknesses, with a bending radius of 4 mm. Figure 3 Figures g and h show that after 1000 repeated bending cycles, the Seebeck coefficient S of silver selenide films of different thicknesses changes very little, with the S value of the 100nm thick film dropping by less than 1.0%. This indicates that the silver selenide film has excellent thermoelectric stability and flexibility under mechanical deformation. In summary, the obtained silver selenide film has stable thermoelectric and mechanical properties, providing a promising material basis for the manufacture of flexible devices.

[0037] 1. Temperature sensing function of silver selenide thin film electronic skin. Figure 4 a is a schematic diagram of the main functions of electronic skin.

[0038] Figure 4 (b) Demonstrates the skin's temperature sensing capability enabled by the thermoelectric properties of silver selenide. As shown in the figure, the electronic skin can keenly detect temperature differences on the surface of an object, and this is verified by the heat distribution displayed by infrared thermal imaging.

[0039] 2. Humidity recognition function of silver selenide thin film electronic skin

[0040] Figure 4 c and Figure 4Figure d shows the voltage response of the electronic skin when in contact with dry and wet surfaces at different temperatures. The electrical waveform generated by the electronic skin is affected by the surface humidity of the material. In particular, when in contact with a wet surface, the voltage output waveform first increases to a peak, then decreases to a negative voltage, and finally returns to its initial state. These phenomena demonstrate that the electronic skin can be used to simultaneously detect an object's temperature and surface humidity.

[0041] 3. Airflow recognition function of silver selenide thin film electronic skin

[0042] Figure 4 Figure e shows the voltage response of the electronic skin when exposed to hot and cold air currents. Since there are few reports of multimodal electronic skins that are highly sensitive to convective airflow, our electronic skin's sensitive response to airflow has potential applications in airflow detection, such as gas detection and respiratory monitoring.

[0043] 4. Contactless sensing function of silver selenide thin film electronic skin

[0044] Figure 4 Figure 5 demonstrates the contactless sensing capability of the proposed electronic skin, using thermal radiation emitted by an object at a distance of 1 mm to 10 mm as an example. This feature is expected to serve as a data input interface for remote sensing and virtual reality.

[0045] 5. Infrared light sensing function of silver selenide thin film electronic skin

[0046] Figure 4 g shows the output voltage response of the electronic skin driven by photothermal-electric conversion when it is exposed to different power densities of 808nm laser radiation.

[0047] 6. Material recognition function of silver selenide thin film electronic skin

[0048] 6.1 Identification Mechanism

[0049] 6.1.1 Mechanism 1

[0050] When the electronic skin is in contact with an object, the temperature of the electronic skin sensing end can be expressed by the following formula:

[0051]

[0052] Where, (kρc) 1 / 2 Represents the contact coefficient, To bject，i represents the initial temperature of the object, and T skin，irepresents the initial skin temperature. In this process, a material's contact coefficient defines its ability to conduct and store heat, thus determining its ability to extract heat from the finger during contact and the contact temperature at the interface. Furthermore, due to the equation "ΔU = S × ΔT," the temperature change of the electronic skin is affected by the contact coefficient, meaning that the maximum voltage is closely related to the material's thermal conductivity, density, and specific heat.

[0053] 6.1.2 Mechanism 2

[0054] The speed at which the electronic skin's temperature increases is affected by the thermal properties of the materials used. First, according to the law of conservation of energy, when the electronic skin comes into contact with other objects, the heat it dissipates (Q E ) is approximately equal to the heat absorbed by the object (Q O ), which is not affected by factors such as contact time, quality of electronic skin, specific heat capacity and thermal conductivity. Therefore, we have Q E =Q O The heat transfer equation can be expressed as:

[0055] Q E =mcΔT (1)

[0056] Where m represents the mass of the electronic skin, c represents the specific heat capacity of the electronic skin, and ΔT represents the temperature difference with the contact area. Then, Fourier's law of heat conduction shows that the heat transfer rate - d Q / dt (or heat per unit time) can be expressed as:

[0057]

[0058] Where k is the thermal conductivity of the material, A is the cross-sectional area where conduction occurs, and l is the length of the material through which conduction occurs. TE and TO represent the temperatures of the electronic skin and the object, respectively.

[0059] Combining these equations, we get:

[0060]

[0061] The Seebeck coefficient (S) is a constant of silver selenide thin films that indicates their ability to convert temperature differences into voltage signals. Therefore, ΔT / t is proportional to the open-circuit voltage ΔU = S × ΔT, which in turn depends on the material's thermal conductivity. The integration of these equations and assumptions establishes a relationship between the electronic skin's temperature change rate, the thermovoltage, and the material's thermal conductivity.

[0062] 6.2 Proof of material identification function To further confirm this, we selected four materials (silver (Ag), polyethylene (PE), polyimide (PI) and polyvinylidene fluoride (PVDF)) for testing ( Figure 4h). When the electronic skin is attached to the touch surface of the finger, heat is quickly transferred to the surface, so when touching different materials, the voltage signal waveform of the electronic skin is recorded ( Figure 4 i, j). In the initial state, the temperature of all materials is room temperature (295K). When the electronic skin contacts the surface of these materials, as the temperature difference increases, the open circuit voltage (Voc) generated by the electronic skin increases. Figure 4 As shown in Figure 1, the order of Voc generated by the electronic skin when in contact with different materials is Ag>PE>PI>PVDF, indicating that silver (Ag) absorbs the most heat, while polyvinylidene fluoride (PVDF) absorbs the least heat. In addition, the trend of the voltage peak is consistent with the order of the contact coefficients of these materials ( Figure 4 l).

[0063] Therefore, by combining the Seebeck effect and the thermal properties of objects, electronic skin can achieve the function of material recognition.

Claims

1. A silver selenide thin film electronic skin with multiple sensing functions based on the thermoelectric effect and a preparation method thereof, characterized in that: The following steps are involved: S1: First, nanosilver is sputtered onto a polyethylene film substrate in an ion sputtering apparatus, and then synthesized into silver selenide through a selenization reaction with a sodium sulfide-selenium solution; S2: After the silver selenide film is prepared, silver electrodes are sputtered to both ends of the silver selenide using an ion sputtering device, one end is the sensing end and the other end is the comparison end; S3: Finally, the film is covered with a polyethylene film for protection.

2. A silver selenide thin film electronic skin with multiple sensing functions based on the thermoelectric effect and a preparation method thereof, characterized in that: The structure includes a sensing layer (1), wherein the sensing layer includes a silver selenide film (11) and a reference silver electrode (12) and a sensing silver electrode (13) at both ends to form the sensing layer; and a synthetic area of ​​the sensing layer forms a base layer (2) on the polyethylene film, and the polyethylene film covering the sensing layer forms a protective layer (3).

3. The silver selenide thin film electronic skin with multiple sensing functions based on the thermoelectric effect and the preparation method thereof according to claim 2 is characterized in that: The thickness of the silver selenide film (11) in the sensing layer (1) is 100 nm, and the length and width are 20 mm*10 mm; the thickness of the reference silver electrode (12) is 100 nm, and the length and width are 10 mm*3 mm; the thickness of the sensing electrode (13) is 100 nm, and the length and width are 20 mm*10 mm.

4. The silver selenide thin film electronic skin with multiple sensing functions based on the thermoelectric effect and the preparation method thereof according to claim 2 is characterized in that: The base layer (2) is a polyethylene film with a thickness of 100 μm and a length and width of 50 mm*10 mm.

5. The silver selenide thin film electronic skin with multiple sensing functions based on the thermoelectric effect and the preparation method thereof according to claim 2 is characterized in that: The protective layer (3) is a polyethylene film with a thickness of 100 μm and a length and width of 50 mm*10 mm.

6. A tactile perception method based on thermoelectric nanogenerator, characterized in that: The silver selenide thin film electronic skin with multiple sensing functions based on the thermoelectric effect and the preparation method thereof according to any one of claims 1 to 4 is used, wherein the method comprises the following steps: S1: collecting electrical signals generated when the electronic skin contacts a contact surface; S2: Processing the electrical signal to obtain an electrical signal that meets preset conditions after processing, and generating a temperature signal, humidity signal, airflow signal, infrared light signal, thermal radiation signal and / or material type signal of the contact surface, identifying the actual material type, temperature signal, humidity, airflow or thermal radiation of the contact surface; and sending the actual material type, humidity, temperature, infrared light, airflow, thermal radiation and other signals to a preset terminal.

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