A kind of air temperature detection device based on fluorescence intensity ratio

Abstract

The utility model provides a kind of air temperature detection device based on fluorescence intensity ratio, the utility model is to solve the low precision of existing temperature measuring device and other problems.The rare earth material piece in the air temperature detection device based on fluorescence intensity ratio of the utility model senses the environmental temperature to be measured, the excitation light of laser is aimed at rare earth material piece, fluorescence light path emitted along rare earth material piece is sequentially provided with first condenser lens, rotating double filter, total reflection mirror and second condenser lens, wherein rotating double filter is rotated by servo motor drive, and different wavelength filter is intervally arranged on rotating double filter;The light emitted by second condenser lens is incident into fluorescence detector, and fluorescence detector converts optical signal into electrical signal and inputs into micro control unit.The air temperature detection device based on fluorescence intensity ratio of the utility model is a kind of air temperature detection device which fuses fluorescence intensity ratio temperature measuring principle and single-chip microcomputer control technology, and can realize non-contact high-precision temperature measurement.

Description

Technical Field

[0001] This utility model belongs to the field of precise temperature measurement technology, specifically relating to an air temperature measuring device based on the fluorescence intensity ratio (FIR) temperature measurement principle. Background Technology

[0002] Temperature, as a fundamental physical quantity, directly impacts production efficiency and quality of life through its measurement accuracy and functional expandability. Current mainstream temperature measurement technologies have significant limitations: contact temperature measurement devices (such as thermocouples and platinum resistance thermometers) require direct contact with the object being measured, making them susceptible to corrosion and mechanical wear, resulting in poor stability and short lifespan in harsh environments; while non-contact infrared thermometers, although requiring no contact, are affected by ambient light interference and differences in object emissivity, often resulting in measurement errors exceeding ±2℃, making them unsuitable for high-precision scenarios.

[0003] At the functional level, existing devices mostly remain at the stage of simple temperature display, presenting values ​​only through digital tubes or LCD screens, lacking intuitive and interactive temperature sensing methods. Furthermore, most devices lack data storage and analysis capabilities, unable to generate historical temperature curves, let alone combine environmental data for trend detection. In addition, the integration of traditional temperature measurement tools with smart terminals is insufficient, making it difficult to adapt to the needs of remote monitoring and intelligent decision-making in the Internet of Things era, limiting their practicality in scenarios such as agricultural irrigation timing judgment, industrial equipment early warning, and daily life planning.

[0004] Rare earth materials exhibit excellent temperature dependence in their fluorescence properties; the fluorescence intensity ratio generated by transitions between different energy levels shows a strictly monotonic functional relationship with temperature. Temperature measurement techniques based on this principle can achieve measurement accuracy at the ±0.1℃ level and possess inherent advantages such as non-contact operation and strong anti-interference capabilities. Existing temperature measurement systems based on fluorescence intensity ratios mostly rely on semi-transparent mirrors for spectral dispersion, resulting in a loss of nearly half the light intensity during the dispersion process. Therefore, designing a temperature measurement device that integrates precise fluorescence excitation, time-division low-loss filtering, STM32 intelligent processing, multimodal interaction, and cloud data analysis has become a key direction for overcoming existing technological bottlenecks. Utility Model Content

[0005] The purpose of this invention is to solve the problems of low accuracy, serious wear and tear, and limited functionality of existing temperature measuring devices, and to provide a temperature detection device based on fluorescence intensity ratio.

[0006] This utility model relates to a temperature detection device based on fluorescence intensity ratio, comprising a laser, a rare earth material component, a first condensing lens, a rotating dual filter, a total reflection mirror, a second condensing lens, a fluorescence detector, and a microcontroller unit. The laser, rare earth material component, first condensing lens, rotating dual filter, total reflection mirror, second condensing lens, fluorescence detector, and microcontroller unit are all housed within a casing. The rare earth material component senses the temperature of the measured environment (object). The excitation light from the laser is aligned with the rare earth material component. Along the fluorescence light path emitted by the rare earth material component, the first condensing lens, rotating dual filter, total reflection mirror, and second condensing lens are sequentially arranged. The rotating dual filter is driven to rotate by a servo motor, and a narrowband filter with wavelength λ1 and a narrowband filter with wavelength λ2 are spaced apart on the rotating dual filter.

[0007] The light emitted from the second focusing lens enters the fluorescence detector, which converts the optical signal into an electrical signal that is then input to the microcontroller unit.

[0008] This novel temperature detection device based on fluorescence intensity ratio consists of a laser, rare-earth material components, a first condensing lens, a (timing) rotating double filter, a total reflection mirror, a second condensing lens, and a fluorescence detector, forming a complete "excitation-filtering-detection" optical path system. The timer in the microcontroller unit is synchronized with the rotation period of the rotating double filter. Each time the motor rotation is triggered, the ADC acquisition is activated, acquiring the voltage signals V1 and V2 corresponding to wavelengths λ1 and λ2, respectively. The temperature value is calculated based on the fluorescence intensity ratio temperature measurement formula T = A + B × ln(V1 / V2), where A and B are the characteristic coefficients of the rare-earth sample (calibrated using a standard constant temperature bath, such as Yb). 3+ :Er 3+ When the sample is doped (A=20.5, B=11.2), the calculation results are stored in the internal Flash memory.

[0009] Compared with the prior art, the temperature detection device based on fluorescence intensity ratio of this invention has the following advantages:

[0010] 1. Excellent measurement accuracy: Based on the principle of rare earth fluorescence intensity ratio, combined with 12-bit ADC acquisition and software noise reduction processing, the measurement error is ≤ ±0.3℃, far exceeding that of infrared thermometers and traditional contact devices, which can meet the needs of high-precision scenarios such as agricultural greenhouses and laboratories; the periodic changes of λ1 and λ2 light intensity are intuitively presented through the fluorescence intensity-time curve, providing reliable data support for accurate temperature calculation.

[0011] 2. Rich interactive experience: It innovatively adopts a rainbow-colored LED gradient temperature display, combined with voice broadcast function, to achieve dual temperature perception of "visual + auditory"; the dual-button design takes into account both manual triggering and timed cancellation, adapting to different usage habits, and is especially easy for the elderly, children and other groups to operate;

[0012] 3. Enhanced Data Value: 24-hour continuous data upload via Bluetooth / WiFi module; mobile app generates visualized curves for easy tracking of temperature change patterns.

[0013] 4. Reasonable structural design: The use of a total reflection mirror optimizes the optical path layout, significantly reducing the size of the device and making the structure more compact; the rechargeable lithium battery pack ensures portability, making it suitable for long-term monitoring in fixed scenarios as well as for mobile temperature measurement needs, with a wide range of applications;

[0014] 5. High scalability: The STM32 main control unit has reserved interfaces such as I2C and SPI, which can be flexibly expanded to include peripherals such as temperature and humidity sensors and OLED displays; the mobile APP supports remote firmware upgrades, which facilitates the addition of new functions and iterations. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the temperature detection device based on fluorescence intensity ratio according to this utility model;

[0016] Figure 2 This is a schematic diagram of the structure of a rotating dual filter;

[0017] Figure 3 This is a schematic diagram of the temperature measurement principle of the air temperature detection device based on fluorescence intensity ratio of this utility model. Detailed Implementation

[0018] Specific Implementation Method 1: This embodiment of the air temperature detection device based on fluorescence intensity ratio includes a laser 1, a rare earth material component 2, a first condensing lens 3, a rotating double filter 4, a total reflection mirror 5, a second condensing lens 6, a fluorescence detector 7, and a microcontroller unit 8. The laser 1, rare earth material component 2, first condensing lens 3, rotating double filter 4, total reflection mirror 5, second condensing lens 6, fluorescence detector 7, and microcontroller unit 8 are all housed inside a housing. The rare earth material component 2 senses the temperature of the measured environment (object). The excitation light of the laser 1 is aligned with the rare earth material component 2. The first condensing lens 3, rotating double filter 4, total reflection mirror 5, and second condensing lens 6 are sequentially arranged along the fluorescence light path emitted by the rare earth material component 2. The rotating double filter 4 is driven to rotate by a servo motor. A narrowband filter 4-1 with a wavelength of λ1 and a narrowband filter 4-2 with a wavelength of λ2 are spaced apart on the rotating double filter 4.

[0019] The light emitted from the second focusing lens 6 enters the fluorescence detector 7, which converts the optical signal into an electrical signal and inputs it to the microcontroller unit 8.

[0020] This embodiment of the air temperature detection device based on fluorescence intensity ratio is an integrated device that combines the fluorescence intensity ratio (FIR) temperature measurement principle with STM32 main control technology. It can realize non-contact high-precision temperature measurement, multi-modal temperature presentation and historical data traceability. It can be widely used for temperature sensing needs in multiple scenarios such as agricultural environmental monitoring, industrial equipment operation and maintenance, and home environmental management.

[0021] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that it supplies power to the laser 1 and the microcontroller unit 8 through the lithium battery pack 13.

[0022] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that there is a blank area between the filter 4-1 with wavelength λ1 and the filter 4-2 with wavelength λ2 on the rotating dual filter 4.

[0023] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method Three in that both the filter 4-1 with wavelength λ1 and the filter 4-2 with wavelength λ2 are fan-shaped.

[0024] Specific Implementation Method 5: This implementation method differs from Specific Implementation Methods 1 to 4 in that the microcontroller unit 8 is electrically connected to the Bluetooth / WiFi module 12.

[0025] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the microcontroller unit 8 is electrically connected to the voice broadcasting device 11.

[0026] Example: This example of a temperature detection device based on fluorescence intensity ratio includes a laser 1, a rare earth material component 2, a first condenser lens 3, a rotating double filter 4, a total reflection mirror 5, a second condenser lens 6, a fluorescence detector 7, and a microcontroller unit 8. The laser 1, rare earth material component 2, first condenser lens 3, rotating double filter 4, total reflection mirror 5, second condenser lens 6, fluorescence detector 7, and microcontroller unit 8 are all housed within a casing. The rare earth material component 2 senses the temperature of the environment being measured. The excitation light from the laser 1 is aligned with the rare earth material component 2 and travels along the rare earth... The fluorescent light path emitted by material component 2 is sequentially provided with a first condenser lens 3, a rotating dual filter 4, a total reflection mirror 5, and a second condenser lens 6. The rotating dual filter 4 is driven to rotate by a servo motor. A narrowband filter 4-1 with a wavelength of λ1 and a narrowband filter 4-2 with a wavelength of λ2 are arranged on the rotating dual filter 4 at intervals. The filter 4-1 with a wavelength of λ1 and the filter 4-2 with a wavelength of λ2 are arranged symmetrically. The interval between the filter 4-1 with a wavelength of λ1 and the filter 4-2 with a wavelength of λ2 is a blank area.

[0027] The light emitted from the second focusing lens 6 enters the fluorescence detector 7, which converts the light signal into an electrical signal and inputs it into the microcontroller 8. The microcontroller 8 is an STM32 microcontroller. The microcontroller 8 is electrically connected to the Bluetooth / WiFi module 12, the temperature-indicating LED light group 9, the dual buttons 10, and the voice broadcast device 11. The lithium battery pack 13 supplies power to the laser 1, the servo motor of the rotating dual filter 4, and the microcontroller 8.

[0028] The air temperature detection device based on fluorescence intensity ratio in this embodiment mainly consists of the following modules, and the functions of each module are as follows:

[0029] 1. Fluorescence excitation and signal processing module (core temperature measurement front end)

[0030] Laser 1 is a narrow-bandwidth semiconductor laser. Its control terminal is connected to the PB0 pin of the STM32 main control unit 8. The laser start and stop control is realized through high and low level signals to ensure that the excitation wavelength is accurately matched with the absorption peak of the rare earth material sample.

[0031] The timed rotating dual filter 4 has two narrowband filters with wavelengths of λ1 and λ2 and a blank area. Its drive motor is connected to the PB1~PB4 pins of the STM32 through the ULN2003 driver board. The rotation period is controlled by the timer TIM2 (which can be set to 1~5 seconds), realizing the alternating acquisition of fluorescence and blank light areas of two characteristic wavelengths.

[0032] The total reflection mirror 5 uses an aluminum-coated reflective mirror and is tilted at 45° in the optical path to achieve a 90° deflection of the fluorescence signal, which greatly optimizes the spatial layout of the device. The first condenser lens 3 and the second condenser lens 6 both use achromatic convex lenses with focal lengths matching the optical path length to ensure efficient convergence of the fluorescence signal.

[0033] The fluorescence detector 7 uses a silicon photodiode in conjunction with a low-noise operational amplifier to convert the fluorescence signal into a mV-level electrical signal. The output is connected to the ADC1_IN0 (PA0) pin of the STM32 microcontroller. This ADC module has 12-bit precision and a sampling rate of up to 1MHz, ensuring accurate signal acquisition. The module can acquire signals as shown in the attached diagram. Figure 3 The fluorescence intensity-time curves shown indicate that current signals i1 and i2 can be converted into voltage signals V1 and V2.

[0034] 2. STM32 signal processing and computing module (system control core)

[0035] The core is an STM32 main control unit 8, which is a model with multiple timers, multiple serial ports and ADC modules, integrating signal acquisition, processing and peripheral control functions;

[0036] Timer TIM3 is synchronized with the rotation period of the timed rotating dual filter 4. Each time the motor is triggered to rotate, the ADC is started to acquire the voltage signals V1 and V2 corresponding to wavelengths λ1 and λ2, respectively, and the dark current interference is eliminated by software.

[0037] The temperature value is calculated based on the fluorescence intensity ratio thermometry formula T = A + B × ln(V1 / V2), where A and B are characteristic coefficients of the rare earth sample (calibrated using a standard constant temperature bath, such as Yb). 3+ :Er 3+ When the sample is doped (A=20.5, B=11.2), the calculation results are stored in the internal Flash memory.

[0038] 3. Temperature display module (human-computer interaction terminal)

[0039] It includes a temperature-indicating LED light group 9, dual buttons 10, and a voice broadcast device 11, enabling multi-dimensional temperature display and interactive control;

[0040] The temperature-sensitive LED light group 9 uses 6 RGB LEDs arranged linearly to form a rainbow color gradient (purple → blue → green → yellow → orange → red). The corresponding temperature range can be configured by software (e.g., evenly divided from 0 to 50℃). Its control pin is connected to the PB5 pin of the STM32, and precise color control is achieved through PWM signal.

[0041] The voice broadcasting device 11 uses a serial port type TTS module, which is connected to the PA2 (TX) and PA3 (RX) pins of the STM32 via USART2, and can broadcast customized voice messages such as "Current temperature 25.3℃" and "Temperature has exceeded the threshold".

[0042] The dual buttons 10 are touch-sensitive buttons, connected to the PA1 and PA4 pins of the STM32 respectively (configured as pull-up input mode), corresponding to the "real-time broadcast" and "cancel timer" functions. When pressed, they trigger a level transition, and the STM32 responds to the interrupt to execute the corresponding operation.

[0043] 4. Temperature Data Analysis Module (Intelligent Extension Unit)

[0044] The core is the Bluetooth / WiFi module 12, which uses a wireless module compatible with dual-mode communication and is connected to the PA9 (TX) and PA10 (RX) pins of the STM32 via USART1;

[0045] Achieve bidirectional data transmission: On the one hand, upload historical data stored in STM32 (1 record every 5 minutes, automatically overwritten after 24 hours) to the mobile APP in real time; on the other hand, receive timing parameters (such as broadcasting once per hour) and threshold setting instructions sent by the mobile APP.

[0046] The mobile app integrates the Deepseek R1 model, combining local historical temperature data with data from official meteorological APIs (including parameters such as humidity, air pressure, and wind speed) to detect temperatures for the next 12 to 24 hours and generate suggestions based on preset rules (such as "The temperature will drop by 5°C tomorrow, it is recommended to wear a jacket" and "No rain in the next 3 days, suitable for wheat irrigation").

[0047] 5. Power supply module (system energy guarantee)

[0048] It consists of a rechargeable lithium battery pack 13 and a power management module, which outputs two voltages: 3.3V and 5V. The 3.3V powers the STM32 main control unit 8 and the Bluetooth / WiFi module 12; the 5V powers the laser 1, the voice broadcast device 11, and the motor drive board, ensuring stable operation of each module. It also supports USB charging and power display functions.

[0049] The usage process of the air temperature detection device based on fluorescence intensity ratio in this embodiment is as follows:

[0050] 1. Optical path calibration and startup

[0051] During device initialization, the STM32 main control unit 8 sends pulse signals to the drive motor of the timing rotating dual filter 4 through the PB1~PB4 pins, causing it to rotate to the Open position. The fluorescence detector 7 collects the ambient light signal and stores it as a reference value.

[0052] When the PB0 pin outputs a high level, it starts laser 1, which emits excitation light of a specific wavelength (such as 405nm blue-violet light) to irradiate rare earth material component 2, thereby exciting it to produce fluorescence.

[0053] 2. Signal Acquisition and Temperature Calculation

[0054] Timer TIM2 triggers the motor to rotate with a period of 2 seconds, switching sequentially to the λ1 filter, λ2 filter and blank area; after the fluorescence is focused by the condenser lens 3, it is filtered by the corresponding filter in a time-division manner to obtain two single-wavelength fluorescences, λ1 and λ2, which are then turned by the total reflection mirror 5 and focused a second time by the condenser lens 6, and finally received by the fluorescence detector 7.

[0055] The detector converts the fluorescence signal into an electrical signal, which is then amplified and transmitted to the PA0 pin of the STM32. The ADC module synchronously acquires and subtracts the reference value to obtain the voltage signals V1 and V2 corresponding to i1 and i2.

[0056] The temperature is calculated using the calibration formula: T = A + B×ln(V1 / V2). The calculation result is accurate to 0.1℃ and stored in the Flash memory.

[0057] 3. Multimodal temperature presentation

[0058] The STM32 controls the output of a PWM signal from the PB5 pin based on the calculated temperature, driving the temperature-indicating LED group 9 to light up the corresponding colors: purple LEDs for 0~10℃, blue LEDs for 11~20℃, green LEDs for 21~30℃, yellow LEDs for 31~40℃, and red LEDs for 41~50℃.

[0059] When the "Real-time Broadcast Button" in the dual-button 10 is pressed, the PA1 pin level changes from high to low. The STM32 sends the instruction "Current temperature XX.X degrees Celsius" to the voice broadcast device 11 through USART2, triggering the voice broadcast. After setting the daily broadcast time at 8:00, 12:00 and 18:00 through the mobile APP, the timer TIM4 will automatically trigger the voice reminder when it reaches the time.

[0060] 4. Data transmission and intelligent monitoring

[0061] The Bluetooth / WiFi module 12 receives temperature data in real time via USART1. After the mobile APP obtains the data via wireless connection, it plots the fluorescence intensity-time curve and the temperature-time curve, and stores 24 hours of historical data.

[0062] 5. Power supply and low power consumption control

[0063] The rechargeable lithium battery pack 13 outputs 11.1V, which is converted to 3.3V and 5V by the power management module to power each module. The STM32 detects the battery voltage and controls the LED group to flash to indicate charging when it is below 9V. In idle state, it automatically enters sleep mode to reduce standby power consumption.

Claims

1. A temperature detection device based on fluorescence intensity ratio, characterized in that... The air temperature detection device based on fluorescence intensity ratio includes a laser (1), a rare earth material component (2), a first condenser lens (3), a rotating double filter (4), a total reflection mirror (5), a second condenser lens (6), a fluorescence detector (7), and a microcontroller unit (8). The laser (1), rare earth material component (2), first condenser lens (3), rotating double filter (4), total reflection mirror (5), second condenser lens (6), fluorescence detector (7), and microcontroller unit (8) are all housed in the housing. The rare earth material component (2) senses the ambient temperature. The excitation light of the laser (1) is aligned with the rare earth material component (2). The first condenser lens (3), rotating double filter (4), total reflection mirror (5), and second condenser lens (6) are arranged sequentially along the fluorescence light path emitted by the rare earth material component (2). The rotating double filter (4) is driven to rotate by a servo motor. The rotating double filter (4) is provided with a filter (4-1) with a wavelength of λ1 and a filter (4-2) with a wavelength of λ2 at intervals. The light emitted from the second focusing lens (6) enters the fluorescence detector (7), and the fluorescence detector (7) converts the optical signal into an electrical signal, which is then input into the microcontroller unit (8).

2. The air temperature detection device based on fluorescence intensity ratio according to claim 1, characterized in that... The laser (1) and the microcontroller (8) are powered by a lithium battery pack (13).

3. The air temperature detection device based on fluorescence intensity ratio according to claim 1, characterized in that... The area between the filter (4-1) with wavelength λ1 and the filter (4-2) with wavelength λ2 on the rotating double filter (4) is blank.

4. The air temperature detection device based on fluorescence intensity ratio according to claim 3, characterized in that... Both the filter (4-1) with wavelength λ1 and the filter (4-2) with wavelength λ2 are fan-shaped.

5. The air temperature detection device based on fluorescence intensity ratio according to claim 1, characterized in that... The microcontroller unit (8) is electrically connected to the Bluetooth / WiFi module (12).

6. The air temperature detection device based on fluorescence intensity ratio according to claim 1, characterized in that... The microcontroller unit (8) is electrically connected to the voice broadcasting device (11).

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