A low-power thermometer based on NFC

Abstract

The present invention relates to a low-power, power-free thermometer based on NFC, including an NFC reading device, a cloud server, and an NFC host module. The NFC host module includes a main control MCU circuit, a WIFI / 2G communication circuit, a power circuit, a radio frequency circuit, and a first induction coil. The NFC reading device includes a reading circuit and a second induction coil. Before use, the first induction coil inside the NFC host module and the second induction coil inside the NFC reading device are electromagnetically inductively coupled to generate current to power the NFC reading device and maintain normal operation. There is no need to add a power module inside the NFC reading device for power supply, which avoids the problem of increasing maintenance costs and shortening service life due to the need to replace a new power supply after a period of use of the ordinary power supply inside the NFC module in the prior art to maintain normal operation of the NFC module, thereby achieving the function of reducing maintenance costs and extending service life.

Description

[Technical field]

[0001] The present invention relates to a thermometer detection instrument, in particular to a low-power and power-free thermometer based on NFC. [Background technology]

[0002] Most of the temperature measuring instruments on the current market are mainly divided into two types: traditional mercury thermometers and electronic thermometers. Although traditional mercury thermometers can detect human body temperature and have a relatively long application time, they are not convenient for long-term continuous temperature monitoring due to the long detection time during measurement and are easy to break, which makes the measurement of the traditional mercury thermometer extremely inconvenient. Subsequently, an electronic thermometer appeared, which adopted a mechanical button wake-up mode to reduce the low power consumption performance of the thermometer and achieve the purpose of detecting body temperature. During the detection process, although the electronic thermometer can overcome the technical defects of the traditional mercury thermometer, the mechanical button wake-up mode inside the electronic thermometer adopts a relatively complex structure, and the electronic components inside the thermometer are often easy to absorb some moisture from the outside, resulting in poor waterproof performance, resulting in a relatively short service life of the electronic thermometer. In order to increase the service life of electronic thermometers, a low-power smart thermometer with NFC is developed. The low-power smart thermometer adopts RFID radio frequency technology, NFC near-field communication technology and low-power chip to realize buttonless design. The electronic thermometer is awakened by the communication function of the NFC module, which can not only reduce the energy consumption of the thermometer, but also simplify the structure and improve the waterproof ability. However, since the NFC module uses a common power supply composed of lithium-ion batteries or button batteries, after a period of use, the common power supply inside the NCF module needs to be replaced with a new power supply to maintain the normal operation of the thermometer, resulting in a relatively high maintenance cost and a relatively short service life of this type of thermometer. [Summary of the invention]

[0003] In view of this, the technical problem to be solved by the present invention is to provide a low-power, power-free thermometer based on NFC, which has the advantages of reducing maintenance costs and extending service life.

[0004] To solve the above technical problems, the technical solution of the present invention adopts a low-power, power-free thermometer based on NFC, which includes an NFC reading device, a cloud server, and an NFC host module for exchanging internal data of the NFC device with internal data of the cloud server; the NFC host module includes a main control MCU circuit, a WIFI / 2G communication circuit, a power circuit, a radio frequency circuit connected to the main control MCU circuit and the WIFI / 2G communication circuit respectively, and a first induction coil connected to the radio frequency circuit; the NFC reading device includes a reading circuit and a second induction coil arranged on the reading circuit; the first induction coil inside the NFC host module and the second induction coil inside the NFC reading device are used for mutual electromagnetic induction to generate current, so as to power the NFC reading device and maintain normal operation.

[0005] It is further defined that the second induction coil includes a target antenna coil; a resistor R3, a resistor R4, a capacitor C4, and a capacitor C5 connected at both ends of the target antenna coil, wherein the resistor R3, the resistor R4, the capacitor C4, and the capacitor C5 are connected in series with each other; a capacitor C2 connected at the intersection of the capacitor C4 and the resistor R3, a resistor R1 connected to the other end of the capacitor C2, and a TNA signal end connected to the other end of the resistor R1; a capacitor C3 connected at the intersection of the capacitor C5 and the resistor R4, a resistor R2 connected to the other end of the capacitor C3, and a TMD signal end connected to the other end of the resistor R2.

[0006] It is further defined that the second induction coil includes a target antenna coil; resistors R7 and R8 connected in parallel at both ends of the target antenna coil, and resistors R7 and R8 are connected in series; capacitors C6 and C7 connected in parallel at both ends of the target antenna coil, and capacitors C6 and C7 are connected in series; capacitor C6 connected to the intersection of capacitor C8 and resistor R7, resistor R5 connected to the other end of capacitor C6, a TNA signal end connected to the other end of resistor R5, capacitor C7 connected to the intersection of capacitor C9 and resistor R8, resistor R6 connected to the other end of capacitor C7, and a TMD signal end connected to the other end of resistor R6.

[0007] It is further defined that the first induction coil includes a launching antenna coil; a resistor R12 and a resistor R13 respectively connected to the launching antenna coil; a capacitor C17 and a capacitor C16 connected between the two ends of the resistor R12 and the resistor R13, and the capacitor C17 and the capacitor C16 are connected in series; the capacitor C12 connected to the intersection of the resistor R12 and the capacitor C17, and the inductor L1 connected to the other end of the capacitor C12, and the inductor L1 is connected to the TX1 end; the capacitor C15 connected to the intersection of the resistor R13 and the capacitor C16, and the inductor L0 connected to the other end of the capacitor C15, and the inductor L0 is connected to the TX1 end; a chip U1 of model CLRC663 connected to both ends of the inductor L1 and the inductor L0, and arranged on the chip RXN interface terminal, VMD interface terminal, TX1 interface terminal, TVSS interface terminal, TX2 interface terminal, VMD1 interface terminal, and RXP interface terminal on U1; capacitor C11 and resistor R9 connected to the VMD0 interface terminal, capacitor C11 and resistor R9 are connected in series with each other; resistor R9 is connected to the VMD1 interface terminal; capacitor C10 connected to the RXN interface terminal, resistor R14 connected to the other end of capacitor C10, capacitor C13 connected to the other end of resistor R14, capacitor C14 connected to the other end of capacitor C13, resistor R12 connected to the other end of capacitor C14, capacitor C17 connected to the other end of resistor R12, and the other end of capacitor C17 is connected to the RXP interface terminal.

[0008] It is further defined that the reading circuit includes an NFC main control chip of model WL1200DFN8, pins 1 to 8 arranged on the NFC main control chip, a capacitor C1 connected between pin 7 and pin 2 of the NFC main control chip, a reference resistor Rref connected between pin 7 and pin 2, a reading resistor NTC, the reference resistor Rref and the reading resistor NTC are connected in series, the intersection of the reference resistor Rref and the reading resistor NTC is connected to pin 8, and the second induction coil is respectively connected to pin 4 and pin 5 on the NFC main control chip.

[0009] It is further defined that the NFC host module also includes a signal acquisition and transmission circuit connected to the main control MCU circuit, and a temperature acquisition circuit; a temperature sensor interconnected with the temperature acquisition circuit, and a first induction coil connected to the signal acquisition and transmission circuit.

[0010] The beneficial technical effects of the present invention are as follows: the NFC host module includes a main control MCU circuit, a WIFI / 2G communication circuit, a power supply circuit, a radio frequency circuit respectively connected to the main control MCU circuit and the WIFI / 2G communication circuit, and a first induction coil connected to the radio frequency circuit. The NFC reading device includes a reading circuit and a second induction coil arranged on the reading circuit. Before use, the electromagnetic induction between the first induction coil inside the NFC host module and the second induction coil inside the NFC reading device is used to generate a current to supply power to the NFC reading device and maintain normal operation. There is no need to add a power supply module inside the NFC reading device for power supply, which avoids the phenomenon that the ordinary power supply inside the NFC module in the prior art needs to be replaced with a new power supply after a period of use to maintain normal operation of the NFC module, thereby increasing its maintenance cost and shortening its service life, thereby achieving the function of reducing maintenance costs and extending service life.

[0011] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

Brief Description of the Drawings

[0012] Figure 1 It is a circuit schematic diagram of the NFC reading device in the present invention;

[0013] Figure 2 This is a circuit diagram of the NFC host module in the present invention;

[0014] Figure 3 This is a working flow chart of the NFC-based low-power, power-free thermometer in the present invention;

[0015] Figure 4 This is a working principle diagram of the NFC-based low-power, power-free thermometer in the present invention;

[0016] Figure 5 This is a working principle diagram of the first and second induction coils in Embodiment 1 of the present invention;

[0017] Figure 6 is a working principle diagram of the first induction coil in the present invention;

[0018] Figure 7 This is a working principle diagram of the first and second induction coils in Example 2 of the present invention. [Specific implementation method]

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] Please refer to Figures 1 to 6As shown, a low-power, power-free thermometer based on NFC is described below in combination with the first embodiment, which includes an NFC reading device, an NFC host module, and a cloud server.

[0021] The NFC reading device includes a reading circuit and a second induction coil arranged on the reading circuit. The reading circuit includes an NFC main control chip of model WL1200DFN8, pins 1 to 8 arranged on the NFC main control chip, a capacitor C1 connected between pin 7 and pin 2 of the NFC main control chip, a reference resistor Rref connected between pin 7 and pin 2, a reading resistor NTC, the reference resistor Rref and the reading resistor NTC are connected in series, the intersection of the reference resistor Rref and the reading resistor NTC is connected to pin 8, and the second induction coil is respectively connected to pins 4 and 5 on the NFC main control chip. In this embodiment, the NFC reading device is a thermometer for detecting the temperature of a human body.

[0022] The NFC host module includes a main control MCU circuit, a WIFI / 2G communication circuit, a power supply circuit, a radio frequency circuit connected to the main control MCU circuit and the WIFI / 2G communication circuit respectively, a first induction coil connected to the radio frequency circuit, a signal acquisition and transmission circuit connected to the main control MCU circuit, and a temperature acquisition circuit; a temperature sensor connected to the temperature acquisition circuit, and a first induction coil connected to the signal acquisition and transmission circuit. The main function of the NFC host module is to exchange data between the internal data of the NFC device and the internal data of the cloud server.

[0023] The second induction coil includes a target antenna coil; a resistor R3, a resistor R4, a capacitor C4, and a capacitor C5 connected at both ends of the target antenna coil, wherein the resistor R3, the resistor R4, the capacitor C4, and the capacitor C5 are connected in series with each other; a capacitor C2 connected at the intersection of the capacitor C4 and the resistor R3, a resistor R1 connected to the other end of the capacitor C2, and a TNA signal end connected to the other end of the resistor R1; a capacitor C3 connected at the intersection of the capacitor C5 and the resistor R4, a resistor R2 connected to the other end of the capacitor C3, and a TMD signal end connected to the other end of the resistor R2.

[0024] The first induction coil includes a launching antenna coil; a resistor R12 and a resistor R13 respectively connected to the launching antenna coil; a capacitor C17 and a capacitor C16 connected between the two ends of the resistor R12 and the resistor R13, wherein the capacitor C17 and the capacitor C16 are connected in series; a capacitor C12 connected to the intersection of the resistor R12 and the capacitor C17, an inductor L1 connected to the other end of the capacitor C12, and the inductor L1 is connected to the TX1 end; a capacitor C15 connected to the intersection of the resistor R13 and the capacitor C16, and an inductor L0 connected to the other end of the capacitor C15, and the inductor L0 is connected to the TX1 end; a chip U1 of model CLRC663 connected to both ends of the inductor L1 and the inductor L0, and arranged on the chip U1 RXN interface end, VMD interface end, TX1 interface end, TVSS interface end, TX2 interface end, VMD1 interface end, RXP interface end; capacitor C11 and resistor R9 connected to the VMDO interface end, capacitor C11 and resistor R9 are connected in series with each other; resistor R9 connected to the VMD1 interface end; capacitor C10 connected to the RXN interface end, resistor R14 connected to the other end of capacitor C10, capacitor C13 connected to the other end of resistor R14, capacitor C14 connected to the other end of capacitor C13, resistor R12 connected to the other end of capacitor C14, capacitor C17 connected to the other end of resistor R12, the other end of capacitor C17 is connected to the RXP interface end.

[0025] The main control MCU circuit is an NFC chip, which is called Near Field Communication in English. NFC is an integration of contactless radio frequency identification (RFID) and interconnection technology. It combines the functions of inductive card reader, inductive card and point-to-point on a single chip, and can identify and exchange data with compatible devices within a short distance. When the NFC chip is installed on a mobile phone, it can read the information of other NFC devices or tags. The short-range interaction of NFC greatly simplifies the entire authentication and identification process, making mutual access between electronic devices more direct, safer and clearer. Through NFC, multiple devices such as computers, digital cameras, mobile phones, PDAs, etc. can be connected wirelessly very conveniently and quickly, thereby realizing data exchange and services. The NFC chip operates at a frequency of 13.56MHz, an unlicensed international frequency band, and is one of the 15 / 18 frequency bands of the US ISM band. The data transmission rate is 106, 212, or 424kbps, depending on the communication range. The transmission rate is maximum at 20cm or about 8 inches. The actual communication range is only a few inches or no more than 10cm. The standard specifies multiple operating modes.

[0026] NFC host modules can exchange data in active or passive mode. In passive mode, the device that starts NFC communication, also known as the NFC initiator (master), provides an RF field during the entire communication process. It can select one of the transmission speeds of 106kbps, 212kbps or 424kbps to send data to another device. The other device, called the NFC target device (slave device), does not have to generate an RF field, but uses load modulation technology, which can transmit data back to the initiator at the same speed. This communication mechanism is compatible with contactless smart cards based on ISO14443A, MIFARE and FetiCa. Therefore, the NFC initiator can detect and establish contact with contactless smart cards or NFC target devices using the same connection and initialization process in passive mode.

[0027] In active mode, each device must generate its own RF field when it wants to send data to the other device. Both the initiator and the target device generate their own RF field in order to communicate. This is the standard mode for peer-to-peer network communication and allows for very fast connection setup. Mobile devices mainly operate in passive mode, which can significantly reduce power consumption and extend battery life. During an application session, NFC devices can switch their roles between initiator and target device. Using this feature, a device with low battery can request to act as a target device in passive mode instead of an initiator.

[0028] Before detection, the NFC reader is close to the NFC host module. The first induction coil inside the NFC host module sends instructions to the initiating antenna coil through the TX1 interface and the TX2 interface, driving the initiating antenna coil to send an induction signal to the target antenna coil through the radio frequency circuit. The induction signal enters from the TNA signal end and passes through the resistor R1 and the capacitor C2 respectively to the target antenna coil. After the target antenna coil and the initiating antenna coil are mutually inductively induced, an induction current is generated. The induction current powers the NFC reader and drives the NFC reader to operate normally after obtaining the current. The main control MCU circuit reads the approaching signal instruction of the NFC reader through the first coil on the radio frequency circuit, and then the main control MCU circuit sends the temperature instruction of the temperature sensor to the NFC reader through the first coil on the radio frequency circuit. After the main control MCU circuit receives the data sent back by the NFC reader, it sends it to the cloud server through the WIFI / 2G communication circuit. The power supply circuit powers all circuits inside the NFC host module. In this process, the first induction coil inside the NFC host module and the second induction coil inside the NFC reader are mutually electromagnetically induced to generate current to power the NFC reader and maintain normal operation. There is no need to add a power module inside the NFC reader to supply power, which avoids the problem that the ordinary power supply inside the NFC module needs to be replaced with a new power supply after being used for a period of time in the prior art to maintain the normal operation of the NFC module, which increases its maintenance cost and shortens its service life, thereby achieving the function of reducing maintenance costs and extending service life.

[0029] In summary, the NFC host module includes a main control MCU circuit, a WIFI / 2G communication circuit, a power supply circuit, a radio frequency circuit connected to the main control MCU circuit and the WIFI / 2G communication circuit respectively, and a first induction coil connected to the radio frequency circuit. The NFC reading device includes a reading circuit and a second induction coil arranged on the reading circuit. Before use, the electromagnetic induction between the first induction coil inside the NFC host module and the second induction coil inside the NFC reading device is used to generate a current to supply power to the NFC reading device and maintain normal operation. There is no need to add a power supply module inside the NFC reading device for power supply, which avoids the problem that the ordinary power supply inside the NFC module in the prior art needs to be replaced with a new power supply after a period of use to maintain normal operation of the NFC module, thereby increasing its maintenance cost and shortening its service life, thereby achieving the function of reducing maintenance costs and extending service life.

[0030] Please refer to Figure 7As shown, the second embodiment is different from the first embodiment in that the second induction coil includes a target antenna coil; resistors R7 and R8 connected in parallel at both ends of the target antenna coil, and resistors R7 and R8 are connected in series; capacitors C6 and C7 connected in parallel at both ends of the target antenna coil, and capacitors C6 and C7 are connected in series; capacitor C6 connected at the intersection of capacitor C8 and resistor R7, resistor R5 connected at the other end of capacitor C6, TNA signal end connected at the other end of resistor R5, capacitor C7 connected at the intersection of capacitor C9 and resistor R8, resistor R6 connected at the other end of capacitor C7, and TMD signal end connected at the other end of resistor R6. The technical effect described in the first embodiment can also be achieved.

[0031] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the present invention is not limited thereby. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention shall be within the scope of the present invention.

Claims

1. A low-power, power-free thermometer based on NFC, comprising an NFC reader, a cloud server, and an NFC host module for exchanging data between the internal data of the NFC device and the internal data of the cloud server; characterized in that : The NFC host module includes a main control MCU circuit, a WIFI / 2G communication circuit, a power circuit, a radio frequency circuit connected to the main control MCU circuit and the WIFI / 2G communication circuit respectively, and a first induction coil connected to the radio frequency circuit; the NFC reading device includes a reading circuit and a second induction coil arranged on the reading circuit; the first induction coil inside the NFC host module and the second induction coil inside the NFC reading device are used to generate a current by electromagnetic induction with each other, so as to supply power to the NFC reading device and maintain normal operation; The second induction coil includes a target antenna coil; a resistor R3, a resistor R4, a capacitor C4, and a capacitor C5 connected at both ends of the target antenna coil, wherein the resistor R3, the resistor R4, the capacitor C4, and the capacitor C5 are connected in series with each other; a capacitor C2 connected at the intersection of the capacitor C4 and the resistor R3, a resistor R1 connected to the other end of the capacitor C2, and a TNA signal end connected to the other end of the resistor R1; a capacitor C3 connected at the intersection of the capacitor C5 and the resistor R4, a resistor R2 connected to the other end of the capacitor C3, and a TMD signal end connected to the other end of the resistor R2; The second induction coil includes a target antenna coil; a resistor R7 and a resistor R8 connected in parallel at both ends of the target antenna coil, and the resistor R7 is connected in series with the resistor R8; a capacitor C6 and a capacitor C7 connected in parallel at both ends of the target antenna coil, and the capacitor C6 is connected in series with the capacitor C7; a capacitor C6 connected at the intersection of the capacitor C8 and the resistor R7, a resistor R5 connected to the other end of the capacitor C6, a TNA signal end connected to the other end of the resistor R5, a capacitor C7 connected at the intersection of the capacitor C9 and the resistor R8, a resistor R6 connected to the other end of the capacitor C7, and a TMD signal end connected to the other end of the resistor R6; The first induction coil includes a launching antenna coil; a resistor R12 and a resistor R13 respectively connected to the launching antenna coil; a capacitor C17 and a capacitor C16 connected between the two ends of the resistor R12 and the resistor R13, wherein the capacitor C17 and the capacitor C16 are connected in series; a capacitor C12 connected to the intersection of the resistor R12 and the capacitor C17, an inductor L1 connected to the other end of the capacitor C12, and the inductor L1 is connected to the TX1 end; a capacitor C15 connected to the intersection of the resistor R13 and the capacitor C16, and an inductor L0 connected to the other end of the capacitor C15, and the inductor L0 is connected to the TX1 end; a chip U1 of model CLRC663 connected to both ends of the inductor L1 and the inductor L0, and arranged on the chip U1 RXN interface end, VMD interface end, TX1 interface end, TVSS interface end, TX2 interface end, VMD1 interface end, RXP interface end; capacitor C11 and resistor R9 connected to the VMD0 interface end, capacitor C11 and resistor R9 are connected in series with each other; resistor R9 connected to the VMD1 interface end; capacitor C10 connected to the RXN interface end, resistor R14 connected to the other end of capacitor C10, capacitor C13 connected to the other end of resistor R14, capacitor C14 connected to the other end of capacitor C13, resistor R12 connected to the other end of capacitor C14, capacitor C17 connected to the other end of resistor R12, the other end of capacitor C17 is connected to the RXP interface end; The reading circuit includes an NFC main control chip of model WL1200DFN8, pins 1 to 8 arranged on the NFC main control chip, a capacitor C1 connected between pin 7 and pin 2 of the NFC main control chip, a reference resistor Rref connected between pin 7 and pin 2, a reading resistor NTC, the reference resistor Rref and the reading resistor NTC are connected in series, the intersection of the reference resistor Rref and the reading resistor NTC is connected to pin 8, and the second induction coil is respectively connected to pin 4 and pin 5 on the NFC main control chip; The NFC host module also includes a signal acquisition and transmission circuit connected to the main control MCU circuit, and a temperature acquisition circuit; a temperature sensor interconnected with the temperature acquisition circuit, and a first induction coil connected to the signal acquisition and transmission circuit.

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