High-precision wireless Bluetooth temperature and humidity meter

Abstract

This invention discloses a high-precision wireless Bluetooth thermometer and hygrometer, relating to the field of thermometer and hygrometer technology. The temperature and humidity sensing module is located in a low-thermal-interference area on the upper edge of the circuit board, away from the Bluetooth chip module, and is used to collect temperature and humidity data. The Bluetooth chip module has a built-in DC-DC power module connected to an RTC timing module. The DC-DC power module is controlled to turn on and off via the Bluetooth chip module. When the high-precision wireless Bluetooth thermometer and hygrometer is in sleep mode, only the RTC timing module operates, and the DC-DC power module enters a light-load mode. When the high-precision wireless Bluetooth thermometer and hygrometer is woken up, the RTC timing module triggers a wake-up signal and wakes up the Bluetooth chip module. The Bluetooth chip module then starts the DC-DC power module to normal efficiency mode, simultaneously controlling the temperature and humidity sensing module to collect temperature and humidity data. After data collection is complete, the high-precision wireless Bluetooth thermometer and hygrometer returns to sleep mode, and the DC-DC power module returns to light-load mode.

Description

Technical Field

[0001] This invention relates to the field of thermo-hygrometer technology, and in particular to a high-precision wireless Bluetooth thermo-hygrometer. Background Technology

[0002] Temperature and humidity are the most fundamental and widely used physical parameters in the field of environmental monitoring. In scenarios such as pharmaceutical cold chain, precision laboratories, semiconductor manufacturing, warehousing and logistics, and high-end instrument calibration, increasingly higher requirements are placed on the accuracy of temperature and humidity measurement, long-term stability, wireless transmission capabilities, and low power consumption. Traditional wired temperature and humidity monitoring equipment has complex wiring, high deployment costs, and poor mobility, making it difficult to meet the needs of distributed, multi-point, and portable monitoring.

[0003] In recent years, Bluetooth Low Energy (BLE) communication technology has been widely used in portable temperature and humidity acquisition devices due to its advantages such as low power consumption, direct connection to mobile phones, no need for gateways, and flexible networking. However, existing Bluetooth temperature and humidity meters generally suffer from the following technical defects: they mostly use ordinary temperature and humidity sensors, resulting in significant cross-interference and hysteresis effects, making it difficult to meet metrology-level measurement requirements; traditional solutions often use external LDOs or independent DC-DC converters, which are inefficient and have high static power consumption, failing to fully utilize the low power potential of BLE SoCs; and the coupling between the external power module and the sensor layout leads to measurement drift, affecting long-term stability. Summary of the Invention

[0004] In view of the above-mentioned shortcomings in the current field of thermo-hygrometer technology, the present invention provides a high-precision wireless Bluetooth thermo-hygrometer that greatly optimizes power consumption, has strong anti-interference ability, high accuracy, and strong adaptability.

[0005] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0006] A high-precision wireless Bluetooth thermometer and hygrometer includes a housing and a circuit board installed inside the housing. The circuit board has a temperature and humidity sensing module, a Bluetooth chip module, and a Bluetooth radio frequency module connected in sequence. The temperature and humidity sensing module is located in a low-thermal-interference area on the upper edge of the circuit board, away from the Bluetooth chip module, and is used to collect temperature and humidity data. The Bluetooth chip module has a built-in DC-DC power module and is connected to an RTC timing module. The DC-DC power module is controlled to turn on and off via the Bluetooth chip module. When the high-precision wireless Bluetooth thermometer and hygrometer is in sleep mode, only the RTC timing module works, and the DC-DC power module enters a light-load mode. When the high-precision wireless Bluetooth thermometer and hygrometer is woken up, the RTC timing module triggers a wake-up signal and wakes up the Bluetooth chip module. The Bluetooth chip module then starts the DC-DC power module to normal efficiency mode, simultaneously controls the temperature and humidity sensing module to collect temperature and humidity data, and after data collection is complete, controls the high-precision wireless Bluetooth thermometer and hygrometer to return to sleep mode, and the DC-DC power module returns to light-load mode.

[0007] According to one aspect of the present invention, the DC-DC power module includes an input terminal VBAT, an output terminal VREG, a PMOS transistor Q1, an NMOS transistor Q2, an inductor L, a driver DRV, and a timer. The input terminal VBAT is connected to the source of the PMOS transistor Q1 and the driver DRV, respectively. The drain of the PMOS transistor Q1 is connected to the switching node SW, the inductor L, and the output terminal VREG in sequence. The input terminal of the driver DRV is connected to the timer, and the output terminal is connected to the gate of the PMOS transistor Q1 and the NMOS transistor Q2, respectively. The drain of the NMOS transistor Q2 is connected to the switching node SW, and the source is connected to power ground PGND. The timer is connected to the clock signal CLK.

[0008] According to one aspect of the present invention, the DC-DC power module further includes a first comparator and a second comparator, the output terminals of the first comparator and the second comparator are connected to a timer, the negative input terminal of the first comparator is connected to a feedback voltage VFB, and the positive input terminal is connected to a reference voltage Vref, the negative input terminal of the second comparator is connected to power ground PGND, and the positive input terminal is connected to a switching node SW.

[0009] According to one aspect of the present invention, the DC-DC power module further includes a first capacitor Cin and a second capacitor Cout, one end of the first capacitor Cin is connected to the input terminal VBAT and the other end is grounded; one end of the second capacitor Cout is connected between the switching node SW and the output terminal VREG and the other end is grounded.

[0010] According to one aspect of the present invention, the DC-DC power module further includes a first voltage divider resistor and a second voltage divider resistor, one end of the first voltage divider resistor being connected to the output terminal VREG and the other end being connected to the negative input terminal of the first comparator; one end of the second voltage divider resistor being connected to the negative input terminal of the first comparator and the other end being grounded.

[0011] According to one aspect of the present invention, the housing includes a lower cover and an upper cover, the upper cover having vent holes covered with a breathable membrane for external moisture to enter and diffuse into the temperature and humidity sensing module.

[0012] According to one aspect of the present invention, the lower cover is provided with a battery compartment, the battery compartment is provided with a battery, and the battery is respectively connected to the Bluetooth chip module and the DC-DC power module.

[0013] According to one aspect of the invention, a data storage module is also included, which is connected to the Bluetooth chip module to provide storage for the Bluetooth chip module.

[0014] According to one aspect of the invention, an antenna is also included, the antenna being connected to the Bluetooth radio frequency module for receiving and transmitting information transmitted by the Bluetooth radio frequency module.

[0015] According to one aspect of the present invention, after the DC-DC power module is restored to light load mode, the high-precision wireless Bluetooth thermometer and hygrometer cycle through sleep and wake-up states.

[0016] The advantages of this invention are: it uses a high-precision sensor to collect temperature and humidity synchronously, and with a reasonable layout, it reduces heat interference. It adopts a Bluetooth chip module with built-in DC-DC architecture, which reduces the overall power consumption by 20%-30% compared to a solution without DC-DC. It does not require an independent MCU or an external power supply chip. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a module for a high-precision wireless Bluetooth thermometer and hygrometer according to the present invention;

[0019] Figure 2 This is a schematic diagram of the DC-DC power module structure of a high-precision wireless Bluetooth thermometer and hygrometer according to the present invention.

[0020] Figure 3This is a schematic diagram of the structure of a high-precision wireless Bluetooth thermometer and hygrometer according to the present invention.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Bottom cover; 2. Top cover; 3. Ventilation holes; 4. Ventilation membrane; 5. Circuit board; 6. Battery compartment. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1

[0025] As shown in the figure, a high-precision wireless Bluetooth thermometer and hygrometer includes a housing and a circuit board 5 installed inside the housing. The circuit board 5 has a temperature and humidity sensing module, a Bluetooth chip module, and a Bluetooth radio frequency module connected in sequence. The Bluetooth chip module has a built-in DC-DC power supply module. It also includes an RTC timing module and a data storage module connected to the Bluetooth chip module, and an antenna connected to the Bluetooth radio frequency module. The data storage module provides storage for the Bluetooth chip module, and the antenna receives and transmits information transmitted by the Bluetooth radio frequency module.

[0026] In this embodiment, the outer shell is made of ceramic with a low coefficient of thermal expansion, and its dimensions are set to 30mm × 20mm × 10mm. It includes a lower cover 1 and an upper cover 2. The upper cover 2 has a vent 3 in the middle, and the vent 3 is covered with a PTFE breathable membrane 4 to prevent dust and liquid water from entering the device, while ensuring that external moisture enters the breathable membrane 4 and diffuses quickly to the temperature and humidity sensing module. The circuit board 5 adopts a double-layer board design with a thickness of 1.6mm. The lower cover 1 has a battery compartment 6, which contains a battery. The battery is connected to the Bluetooth chip module and the DC-DC power module respectively.

[0027] The temperature and humidity sensing module employs the SHT45 high-precision digital temperature and humidity sensor, a single-chip integrated design powered by a DC-DC power module at 1.8V. It can simultaneously acquire raw data of ambient temperature and relative humidity, eliminating the need for discrete sensors. The module is factory-calibrated to a temperature error of ±0.1℃ and a humidity error of ±1.0%RH. It features an I2C interface for connection to the Bluetooth chip module, ensuring stable communication without external signal conditioning circuitry. It supports configurable acquisition frequencies ranging from 1 time / 10s to 1 time / 5 minutes; in this embodiment, it is set to 1 time / 1 minute. Each acquisition continuously reads 8 raw data points, employing a moving average filter to reduce measurement noise. Furthermore, in this embodiment, the temperature and humidity sensing module is positioned on the upper edge of the circuit board 5 in a low-heat interference area, away from the core heat-generating area of ​​the Bluetooth chip module, at a distance exceeding 10mm. An aerogel thermal insulation strip is also incorporated to reduce measurement drift caused by heat conduction.

[0028] The Bluetooth chip module uses a BLE single-chip SoC with a built-in DC-DC power module as the main controller. In this embodiment, the Bluetooth chip module is the Silicon Labs EFR32BG22, which integrates the processor, Bluetooth RF module, data storage unit, and DC-DC power module without the need for an additional independent MCU or power chip. The Bluetooth chip module directly reads the temperature and humidity data from the temperature and humidity sensor module through the I2C interface, eliminating the need for an additional MCU for data forwarding and processing. The built-in DC-DC power module eliminates the need for external power components other than inductors or capacitors, simplifying the circuit and reducing costs. The built-in low-power processor can perform functions such as data filtering, storage, and Bluetooth broadcasting.

[0029] The DC-DC power module is controlled to turn on and off via a Bluetooth chip module. In this embodiment, the EFR32BG22 model is used, including an input terminal VBAT, an output terminal VREG, a PMOS transistor Q1, an NMOS transistor Q2, an inductor L, a driver DRV, a timer, a first comparator, and a second comparator. The input terminal VBAT is connected to the source of PMOS transistor Q1 and the driver DRV. The drain of PMOS transistor Q1 is connected to the switching node SW, the inductor L, and the output terminal VREG in sequence. The input terminal of the driver DRV is connected to the timer, and the output terminal is connected to the gates of PMOS transistor Q1 and NMOS transistor Q2. The drain of NMOS transistor Q2 is connected to the switching node SW, and the source is connected to power ground PGND. The timer is connected to the clock signal CLK and the output terminals of the first and second comparators. The negative input terminal of the first comparator is connected to the feedback voltage VFB, and the positive input terminal is connected to the reference voltage Vref. The negative input terminal of the second comparator is connected to power ground PGND, and the positive input terminal is connected to the switching node SW. It also includes a first voltage divider resistor and a second voltage divider resistor. One end of the first voltage divider resistor is connected between the inductor L and the output terminal VREG, and the other end is connected to the negative input terminal of the first comparator. One end of the second voltage divider resistor is connected to the negative input terminal of the first comparator, and the other end is grounded. It also includes a first capacitor Cin and a second capacitor Cout. One end of the first capacitor Cin is connected to the input terminal VBAT, and the other end is grounded. One end of the second capacitor Cout is connected between the switching node SW and the output terminal VREG, and the other end is grounded. When the feedback voltage VFB is lower than the reference voltage Vref, the state machine is triggered. At the rising edge of the clock signal CLK, the PMOS transistor Q1 is turned on. The conduction time of the upper PMOS transistor is TON value × Tosc. At this time, the current IL of the inductor L rises. The voltage measured at the VSW pin during this stage is the VBAT voltage. When the upper PMOS transistor Q1 is turned on by TON × Tosc, the state machine immediately turns off Q1 and turns on the lower NMOS transistor Q2. The current IL of inductor L begins to decrease. During this stage, the voltage at the VSW pin is measured to be 0V. When the inductor current drops to around 0mA, the inductor current IL begins to reverse. At this time, the voltage at PGND is greater than the voltage at VSW, triggering the state machine to turn off the lower NMOS transistor. During the turn-on stage of the lower NMOS transistor Q2, because the downstream load consumes relatively little power during this period, the feedback voltage VFB has not yet dropped to the reference voltage Vref. Therefore, during this stage, both the upper PMOS transistor Q1 and the lower NMOS transistor Q2 are in the off state, and the inductor current IL is 0mA. The voltage across VSW measured during this stage is the voltage VREG across the second capacitor Cout. As the load continues to consume power, the voltage of the second capacitor Cout decreases, causing the feedback voltage VFB to drop below the reference voltage Vref. At this time, the state machine is triggered, turning on the PMOS transistor at the rising edge of the clock signal CLK, and repeating the above process.

[0030] The input voltage VBAT ranges from 1.71V to 3.8V and is powered by a lithium-ion battery or a button cell. In this embodiment, only an external 1μH inductor and a 0.1μF filter capacitor are connected. The input voltage is 3.6V, which supplies 1.8V to the temperature and humidity sensing module and 3.3V to the Bluetooth chip module. The DC-DC power module supports a light-load high-efficiency mode with a static power consumption of <1μA and an overall efficiency of over 90%. Compared to not using a DC-DC solution, the overall power consumption is reduced by 20%-30%, while the maximum output current reaches 60mA, which can meet the power supply requirements of the temperature and humidity sensing module and the Bluetooth chip module under all operating conditions. When the high-precision wireless Bluetooth thermometer and hygrometer is in sleep mode, the device is mostly in EM4 off mode, with only the RTC timing module operating. The DC-DC power module enters light-load mode, and the temperature and humidity sensing module enters low-power standby mode, with the overall current not exceeding 0.17μA. When the high-precision wireless Bluetooth thermometer and hygrometer is woken up, the RTC timing module triggers a wake-up signal at a preset time interval (3s-1min), waking up the Bluetooth chip module. The Bluetooth chip module then activates the DC-DC power module to normal efficiency mode and controls the temperature and humidity sensing module to collect temperature and humidity data. After data collection, the Bluetooth chip module quickly performs data filtering and storage, then controls the high-precision wireless Bluetooth thermometer and hygrometer to enter EM4 off mode and return to sleep mode. The DC-DC power module returns to light-load mode, and the high-precision wireless Bluetooth thermometer and hygrometer cycle through sleep and wake-up states to minimize power consumption.

[0031] When the high-precision wireless Bluetooth thermometer and hygrometer is powered on, the built-in DC-DC power module starts up, supplying power to the Bluetooth chip module and the temperature and humidity sensing module. The Bluetooth chip module completes initialization and loads preset operating parameters. The Bluetooth chip module controls the temperature and humidity sensing module to start, continuously collecting raw temperature and humidity data eight times, performing moving average filtering to obtain the current temperature and humidity data. The Bluetooth chip module encrypts the processed temperature and humidity data using AES-128 and sends it via Bluetooth broadcast. After the broadcast is complete, the control device enters EM4 shutdown mode. The RTC timing module triggers wake-up at 1-second intervals, repeating the above data acquisition and broadcast process. During sleep, the built-in DC-DC power module enters a light-load mode to further reduce power consumption.

[0032] Advantages of this invention: The temperature and humidity sensing module is located in a low-heat interference area on the upper edge of the circuit board and away from the Bluetooth chip module. It is used to collect temperature and humidity data. The Bluetooth chip module has a built-in DC-DC power module and is connected to the RTC timing module. The DC-DC power module is controlled to turn on and off through the Bluetooth chip module. When the high-precision wireless Bluetooth temperature and humidity meter is in sleep mode, only the RTC timing module works, and the DC-DC power module enters a light-load mode. When the high-precision wireless Bluetooth temperature and humidity meter is woken up, the RTC timing module triggers a wake-up signal and wakes up the Bluetooth chip module. The Bluetooth chip module starts the DC-DC power module to normal efficiency mode and simultaneously controls the temperature and humidity sensing module to collect temperature and humidity data. After the data collection is completed, it controls the high-precision wireless Bluetooth temperature and humidity meter to return to sleep mode, and the DC-DC power module returns to the light-load mode. Using a high-precision sensor, temperature and humidity are collected synchronously. With reasonable layout, heat interference is reduced. The Bluetooth chip module has a built-in DC-DC architecture, which reduces the overall power consumption by 20%-30% compared to a solution without DC-DC. No independent MCU or external power chip is required.

[0033] Example 2

[0034] As shown in the figure, a high-precision wireless Bluetooth thermometer and hygrometer includes a housing and a circuit board 5 installed inside the housing. The circuit board 5 has a temperature and humidity sensing module, a Bluetooth chip module, and a Bluetooth radio frequency module connected in sequence. The Bluetooth chip module has a built-in DC-DC power supply module. It also includes an RTC timing module and a data storage module connected to the Bluetooth chip module, and an antenna connected to the Bluetooth radio frequency module. The data storage module provides storage for the Bluetooth chip module, and the antenna receives and transmits information transmitted by the Bluetooth radio frequency module.

[0035] In this embodiment, the outer shell is made of engineering plastic with a low coefficient of thermal expansion, and its dimensions are set to 30mm × 20mm × 10mm. It includes a lower cover 1 and an upper cover 2. The upper cover 2 has a vent 3 in the middle, and the vent 3 is covered with a PTFE breathable membrane 4 to prevent dust and liquid water from entering the device, while ensuring that external moisture enters the breathable membrane 4 and diffuses quickly to the temperature and humidity sensing module. The circuit board 5 adopts a double-layer board design with a thickness of 1.6mm. The lower cover 1 has a battery compartment 6, which contains a battery. The battery is connected to the Bluetooth chip module and the DC-DC power module respectively.

[0036] The temperature and humidity sensing module employs the SHT45 high-precision digital temperature and humidity sensor, a single-chip integrated design powered by a DC-DC power module at 1.8V. It can simultaneously acquire raw data of ambient temperature and relative humidity, eliminating the need for discrete sensors. The module is factory-calibrated to a temperature error of ±0.1℃ and a humidity error of ±1.0%RH. It features an I2C interface for connection to the Bluetooth chip module, ensuring stable communication without external signal conditioning circuitry. It supports configurable acquisition frequencies ranging from 1 time / 10s to 1 time / 5 minutes; in this embodiment, it is set to 1 time / 1 minute. Each acquisition continuously reads 8 raw data points, employing a moving average filter to reduce measurement noise. Furthermore, in this embodiment, the temperature and humidity sensing module is positioned on the upper edge of the circuit board 5 in a low-heat interference area, away from the core heat-generating area of ​​the Bluetooth chip module, at a distance exceeding 10mm. An aerogel thermal insulation strip is also incorporated to reduce measurement drift caused by heat conduction.

[0037] The Bluetooth chip module uses a BLE single-chip SoC with a built-in DC-DC power module as the main controller. In this embodiment, the Bluetooth chip module is the Silicon Labs EFR32BG22, which integrates the processor, Bluetooth RF module, data storage unit, and DC-DC power module without the need for an additional independent MCU or power chip. The Bluetooth chip module directly reads the temperature and humidity data from the temperature and humidity sensor module through the I2C interface, eliminating the need for an additional MCU for data forwarding and processing. The built-in DC-DC power module eliminates the need for external power components other than inductors or capacitors, simplifying the circuit and reducing costs. The built-in low-power processor can perform functions such as data filtering, storage, and Bluetooth broadcasting.

[0038] The DC-DC power module is controlled to turn on and off via a Bluetooth chip module. In this embodiment, the EFR32BG22 model is used, including an input terminal VBAT, an output terminal VREG, a PMOS transistor Q1, an NMOS transistor Q2, an inductor L, a driver DRV, a timer, a first comparator, and a second comparator. The input terminal VBAT is connected to the source of PMOS transistor Q1 and the driver DRV. The drain of PMOS transistor Q1 is connected to the switching node SW, the inductor L, and the output terminal VREG in sequence. The input terminal of the driver DRV is connected to the timer, and the output terminal is connected to the gates of PMOS transistor Q1 and NMOS transistor Q2. The drain of NMOS transistor Q2 is connected to the switching node SW, and the source is connected to power ground PGND. The timer is connected to the clock signal CLK and the output terminals of the first and second comparators. The negative input terminal of the first comparator is connected to the feedback voltage VFB, and the positive input terminal is connected to the reference voltage Vref. The negative input terminal of the second comparator is connected to power ground PGND, and the positive input terminal is connected to the switching node SW. It also includes a first voltage divider resistor and a second voltage divider resistor. One end of the first voltage divider resistor is connected between the inductor L and the output terminal VREG, and the other end is connected to the negative input terminal of the first comparator. One end of the second voltage divider resistor is connected to the negative input terminal of the first comparator, and the other end is grounded. It also includes a first capacitor Cin and a second capacitor Cout. One end of the first capacitor Cin is connected to the input terminal VBAT, and the other end is grounded. One end of the second capacitor Cout is connected between the switching node SW and the output terminal VREG, and the other end is grounded. When the feedback voltage VFB is lower than the reference voltage Vref, the state machine is triggered. At the rising edge of the clock signal CLK, the PMOS transistor Q1 is turned on. The conduction time of the upper PMOS transistor is TON value × Tosc. At this time, the current IL of the inductor L rises. The voltage measured at the VSW pin during this stage is the VBAT voltage. When the upper PMOS transistor Q1 is turned on by TON × Tosc, the state machine immediately turns off Q1 and turns on the lower NMOS transistor Q2. The current IL of inductor L begins to decrease. During this stage, the voltage at the VSW pin is measured to be 0V. When the inductor current drops to around 0mA, the inductor current IL begins to reverse. At this time, the voltage at PGND is greater than the voltage at VSW, triggering the state machine to turn off the lower NMOS transistor. During the turn-on stage of the lower NMOS transistor Q2, because the downstream load consumes relatively little power during this period, the feedback voltage VFB has not yet dropped to the reference voltage Vref. Therefore, during this stage, both the upper PMOS transistor Q1 and the lower NMOS transistor Q2 are in the off state, and the inductor current IL is 0mA. The voltage across VSW measured during this stage is the voltage VREG across the second capacitor Cout. As the load continues to consume power, the voltage of the second capacitor Cout decreases, causing the feedback voltage VFB to drop below the reference voltage Vref. At this time, the state machine is triggered, turning on the PMOS transistor at the rising edge of the clock signal CLK, and repeating the above process.

[0039] The input voltage VBAT ranges from 1.71V to 3.8V and is powered by a lithium-ion battery or a button cell. In this embodiment, only an external 1μH inductor and a 0.1μF filter capacitor are connected. The input voltage is 3.6V, which supplies 1.8V to the temperature and humidity sensing module and 3.3V to the Bluetooth chip module. The DC-DC power module supports a light-load high-efficiency mode with a static power consumption of <1μA and an overall efficiency of over 90%. Compared to not using a DC-DC solution, the overall power consumption is reduced by 20%-30%, while the maximum output current reaches 60mA, which can meet the power supply requirements of the temperature and humidity sensing module and the Bluetooth chip module under all operating conditions. When the high-precision wireless Bluetooth thermometer and hygrometer is in sleep mode, the device is mostly in EM4 off mode, with only the RTC timing module operating. The DC-DC power module enters light-load mode, and the temperature and humidity sensing module enters low-power standby mode, with the overall current not exceeding 0.17μA. When the high-precision wireless Bluetooth thermometer and hygrometer is woken up, the RTC timing module triggers a wake-up signal at a preset time interval (3s-1min), waking up the Bluetooth chip module. The Bluetooth chip module then activates the DC-DC power module to normal efficiency mode and controls the temperature and humidity sensing module to collect temperature and humidity data. After data collection, the Bluetooth chip module quickly performs data filtering and storage, then controls the high-precision wireless Bluetooth thermometer and hygrometer to enter EM4 off mode and return to sleep mode. The DC-DC power module returns to light-load mode, and the high-precision wireless Bluetooth thermometer and hygrometer cycle through sleep and wake-up states to minimize power consumption.

[0040] When the high-precision wireless Bluetooth thermometer and hygrometer is powered on, the built-in DC-DC power module starts up, supplying power to the Bluetooth chip module and the temperature and humidity sensing module. The Bluetooth chip module completes initialization and loads preset operating parameters. The Bluetooth chip module controls the temperature and humidity sensing module to start, continuously collecting raw temperature and humidity data eight times, performing moving average filtering to obtain the current temperature and humidity data. The Bluetooth chip module encrypts the processed temperature and humidity data using AES-128 and sends it via Bluetooth broadcast. After the broadcast is complete, the control device enters EM4 shutdown mode. The RTC timing module triggers wake-up at 1-second intervals, repeating the above data acquisition and broadcast process. During sleep, the built-in DC-DC power module enters a light-load mode to further reduce power consumption.

[0041] Advantages of this invention: The temperature and humidity sensing module is located in a low-heat interference area on the upper edge of the circuit board and away from the Bluetooth chip module. It is used to collect temperature and humidity data. The Bluetooth chip module has a built-in DC-DC power module and is connected to the RTC timing module. The DC-DC power module is controlled to turn on and off through the Bluetooth chip module. When the high-precision wireless Bluetooth temperature and humidity meter is in sleep mode, only the RTC timing module works, and the DC-DC power module enters a light-load mode. When the high-precision wireless Bluetooth temperature and humidity meter is woken up, the RTC timing module triggers a wake-up signal and wakes up the Bluetooth chip module. The Bluetooth chip module starts the DC-DC power module to normal efficiency mode and simultaneously controls the temperature and humidity sensing module to collect temperature and humidity data. After the data collection is completed, it controls the high-precision wireless Bluetooth temperature and humidity meter to return to sleep mode, and the DC-DC power module returns to the light-load mode. Using a high-precision sensor, temperature and humidity are collected synchronously. With reasonable layout, heat interference is reduced. The Bluetooth chip module has a built-in DC-DC architecture, which reduces the overall power consumption by 20%-30% compared to a solution without DC-DC. No independent MCU or external power chip is required.

[0042] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high-precision wireless Bluetooth hygrometer comprising a housing and a circuit board installed inside the housing, characterized in that, The circuit board is equipped with a temperature and humidity sensing module, a Bluetooth chip module, and a Bluetooth radio frequency module connected in sequence. The temperature and humidity sensing module is located in the low thermal interference area on the upper edge of the circuit board and away from the Bluetooth chip module. It is used to collect temperature and humidity data. The Bluetooth chip module has a built-in DC-DC power module and is connected to the RTC timing module. The DC-DC power module is controlled to turn on and off through the Bluetooth chip module. When the high-precision wireless Bluetooth thermometer and hygrometer is in sleep mode, only the RTC timing module works, and the DC-DC power module enters light load mode. When the high-precision wireless Bluetooth thermometer and hygrometer is woken up, the RTC timing module triggers a wake-up signal and wakes up the Bluetooth chip module. The Bluetooth chip module starts the DC-DC power module to normal efficiency mode, and at the same time controls the temperature and humidity sensing module to collect temperature and humidity data. After the data collection is completed, it controls the high-precision wireless Bluetooth thermometer and hygrometer to return to sleep mode, and the DC-DC power module returns to light load mode.

2. The high precision wireless Bluetooth thermohygro meter according to claim 1, characterized in that, The DC-DC power module includes an input terminal VBAT, an output terminal VREG, a PMOS transistor Q1, an NMOS transistor Q2, an inductor L, a driver DRV, and a timer. The input terminal VBAT is connected to the source of the PMOS transistor Q1 and the driver DRV. The drain of the PMOS transistor Q1 is connected to the switching node SW, the inductor L, and the output terminal VREG in sequence. The input terminal of the driver DRV is connected to the timer, and the output terminal is connected to the gates of the PMOS transistor Q1 and the NMOS transistor Q2. The drain of the NMOS transistor Q2 is connected to the switching node SW, and the source is connected to power ground PGND. The timer is connected to the clock signal CLK.

3. The high precision wireless Bluetooth thermohygro meter according to claim 2, characterized in that, The DC-DC power module further includes a first comparator and a second comparator. The output terminals of the first and second comparators are connected to a timer. The negative input terminal of the first comparator is connected to the feedback voltage VFB, and the positive input terminal is connected to the reference voltage Vref. The negative input terminal of the second comparator is connected to the power ground PGND, and the positive input terminal is connected to the switching node SW.

4. The high precision wireless Bluetooth thermohygro meter according to claim 2, characterized in that, The DC-DC power module also includes a first capacitor Cin and a second capacitor Cout. One end of the first capacitor Cin is connected to the input terminal VBAT, and the other end is grounded. One end of the second capacitor Cout is connected between the switching node SW and the output terminal VREG, and the other end is grounded.

5. The high precision wireless Bluetooth thermohygro meter according to claim 3, characterized in that, The DC-DC power module also includes a first voltage divider resistor and a second voltage divider resistor. One end of the first voltage divider resistor is connected to the output terminal VREG, and the other end is connected to the negative input terminal of the first comparator. One end of the second voltage divider resistor is connected to the negative input terminal of the first comparator, and the other end is grounded.

6. The high precision wireless Bluetooth thermohygro meter according to claim 1, characterized in that, The housing includes a lower cover and an upper cover. The upper cover is provided with vent holes, and the vent holes are covered with a breathable membrane to allow external moisture to enter and diffuse to the temperature and humidity sensing module.

7. The high precision wireless Bluetooth thermohygro meter according to claim 6, characterized in that, The lower cover has a battery compartment containing a battery, which is connected to the Bluetooth chip module and the DC-DC power module.

8. The high precision wireless Bluetooth thermohygro meter according to claim 1, characterized in that, It also includes a data storage module, which is connected to the Bluetooth chip module to provide storage for the Bluetooth chip module.

9. The high precision wireless Bluetooth thermohygro meter according to claim 1, characterized in that, Also include an antenna, the antenna with the bluetooth radio frequency module interface, for receiving and transmitting the bluetooth radio frequency module delivery information.

10. The high precision wireless Bluetooth thermohygro meter according to any of claims 1 to 9, characterized in that, After the DCDC power module recovers to the light load mode, the high-precision wireless bluetooth temperature and humidity meter circulates the sleep state and the wake-up state process.

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