CN111289120A - Low-cost fixed-distance infrared temperature measuring device and method - Google Patents

Abstract

The invention discloses a low-cost distance infrared temperature measuring device and a method, which are realized by matching an infrared temperature measuring device with a distance compensation method, wherein the infrared temperature measuring device consists of a reflective distance measuring switch, an optical lens, an infrared temperature measuring probe, a sound prompting circuit, a conditioning circuit, a singlechip, a power supply, a communication interface and an LED (light emitting diode) indicator; the optical lens focuses infrared light emitted by a measured object and projects the infrared light to the infrared temperature measuring probe, the conditioning circuit conditions an electric signal emitted by the infrared temperature measuring probe, and outputs an amplified voltage signal and sends the amplified voltage signal to the analog input port of the single chip microcomputer; the distance measuring switch measures whether the object is in the measuring range, and directly connects the output switching value signal to the single chip microcomputer, and the single chip microcomputer carries out temperature compensation according to the measuring signal and a specific distance compensation method.

Description

A low-cost fixed-distance infrared temperature measurement device and method

technical field

The invention relates to a low-cost fixed-distance infrared temperature measurement device and method, and is specifically applied to high-precision infrared temperature measurement applications.

Background technique

In 1800, the British physicist F.W. Huxell discovered infrared rays when he studied various colors of light from a thermal point of view. Infrared is an electromagnetic wave that has the same nature as radio waves and visible light. The wavelength of infrared rays is between 0.76 and 1000 μm. According to the wavelength range, it can be divided into four categories: near-infrared, mid-infrared, far-infrared, and extremely far-infrared. Its position in the continuous spectrum of electromagnetic waves is the area between radio waves and visible light. . In recent years, infrared thermometer technology has developed rapidly, with perfect performance, continuous enhancement of functions, continuous increase of varieties, and continuous expansion of application scope. Compared with contact temperature measurement methods, infrared temperature measurement has the advantages of fast response time, non-contact, safe use, and long service life. Non-contact infrared thermometers are composed of three series of portable (hand-held), online scanning, various options and computer software, each with various models and specifications.

Infrared thermometer consists of optical system, photodetector, signal amplifier, signal processing, display output and other parts. The optical system concentrates the infrared radiation energy of the target in its field of view, and the size of the field of view is determined by the optical parts of the thermometer and their positions. The infrared energy is focused on a photodetector and converted into a corresponding electrical signal. The signal is converted into the temperature value of the measured target after being corrected by the amplifier and signal processing circuit and corrected according to the algorithm of the internal therapy of the instrument and the target emissivity.

Infrared temperature measurement is related to distance. Under the condition of constant infrared radiation intensity and constant receiving angle of infrared sensor, the longer the distance from the target, the lower the temperature, showing a nonlinear relationship. In general, many infrared temperature measurement devices will add non-contact distance sensors. However, the measurement accuracy of the non-contact distance measuring sensor is affected by many factors, such as the angle of the reflective surface of the material. In addition, the high-precision non-contact distance measuring sensor is expensive, which increases the cost of the temperature measuring device.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a low-cost fixed-distance infrared temperature measurement device and method.

The above-mentioned technical purpose of the present invention is achieved through the following technical solutions:

A low-cost fixed-distance infrared temperature measurement method is realized by using an infrared temperature measurement device and a distance compensation method. It consists of a circuit, a single-chip microcomputer, a power supply, a communication interface and an LED indication; the optical lens focuses the infrared light emitted by the measured object and projects it to the infrared temperature measuring probe. The conditioning circuit adjusts the electrical signal sent by the infrared temperature measuring probe, and the output is amplified The voltage signal is sent to the analog input port of the single-chip microcomputer; the reflective ranging switch measures whether the object is within the measurement range, and directly connects the measurement signal of the reflective ranging switch to the single-chip computer. Perform temperature compensation. The distance compensation method uses the object to approach the temperature measuring device from far to near, measures the temperature according to the signal change of the reflective distance measuring switch, and outputs the compensated temperature through the temperature compensation formula.

The specific operation steps of the above distance compensation method are as follows:

Step 1. The measured object approaches the temperature measuring device from far to near. When the signal of the reflective ranging switch changes, the single-chip microcomputer sends out a prompt through a sound signal;

Step 2. After hearing the prompt sound, the measured object stops moving, the LED light starts to flash, and the temperature measurement starts, and the single-chip microcomputer collects the voltage value of the conditioning circuit;

Step 3. In about 1 second, the temperature signal value of the measured object tends to be stable, stop the sampling work, and the measured object ends the distance is maintained;

Step 4, temperature compensation calculation, the calculation formula is: T=T ₀ +ΔT, where T is the target temperature, T ₀ is the temperature before distance compensation, and ΔT is the compensation difference;

Step 5: Send the measurement results to the data acquisition device through the communication interface.

The calculation formula of the compensation difference is: ΔT=f(l,t), where f is the compensation function, l is the distance changed by the reflective ranging switch, and t is the ambient temperature; the compensation function f uses binary linear regression, through Experimental data obtained.

Another object of the application of the present invention is to provide a low-cost fixed-distance infrared temperature measurement device, which consists of a reflective distance measurement switch, an optical lens, an infrared temperature measurement probe, a sound prompt circuit, a conditioning circuit, a single-chip microcomputer, a power supply, a communication interface and an LED. Indication composition; optical lens, infrared temperature probe and single-chip microcomputer are electrically connected in sequence, reflective ranging switch, sound prompt circuit, communication interface and LED indication are all electrically connected to the single-chip microcomputer, and the power supply supplies power for the entire device; sound prompt circuit and LED The prompt is used to prompt the ranging process.

To sum up, the beneficial effects of the present invention compared with the prior art are:

The infrared light emitted by the object to be measured is focused through the optical lens, and projected to the infrared temperature measuring probe. The conditioning circuit adjusts the electrical signal sent by the infrared temperature measuring probe, outputs the amplified voltage signal, and sends it to the analog input port of the microcontroller. The reflective ranging switch measures whether the object is within the measurement range, and directly connects the measurement signal of the reflective ranging switch to the single-chip microcomputer. The above distance compensation method greatly improves the measurement accuracy of the temperature measuring device, and does not require a high-precision non-contact distance measuring sensor, thereby reducing the cost of the temperature measuring device.

Description of drawings

Fig. 1 is the frame diagram of the temperature measuring device of the embodiment;

FIG. 2 is a schematic diagram of the use of the temperature measuring device of the embodiment.

Detailed ways

The invention will be further described in detail below in conjunction with the accompanying drawings.

A low-cost fixed-distance infrared temperature measurement device, as shown in Figure 1, consists of a reflective distance measurement switch, an optical lens, an infrared temperature measurement probe, a sound prompt circuit, a conditioning circuit, a single-chip microcomputer, a power supply, a communication interface and an LED indication; The optical lens, the infrared temperature measuring probe and the single-chip microcomputer are electrically connected in sequence. The reflective ranging switch, the sound prompt circuit, the communication interface and the LED indication are all electrically connected to the single chip computer. The power supply supplies power to the entire device; the sound prompt circuit and the LED prompt are used for Prompt the ranging process.

The optical lens focuses the infrared light emitted by the object to be measured and projects it to the infrared temperature measuring probe. The conditioning circuit adjusts the electrical signal sent by the infrared temperature measuring probe, outputs the amplified voltage signal, and sends it to the analog input port of the microcontroller; The reflective ranging switch measures whether the object is within the measurement range, and directly connects the measurement signal of the reflective ranging switch to the single-chip microcomputer. The single-chip computer performs temperature compensation according to the measurement signal according to a specific distance compensation method. The distance compensation method passes the object from far to near. Approach the temperature measuring device, measure the temperature according to the signal change of the reflective ranging switch, and output the compensated temperature through the temperature compensation formula.

The specific operation steps of the above distance compensation method are as follows:

Step 1. The measured object approaches the temperature measuring device from far to near. When the signal of the reflective ranging switch changes, the single-chip microcomputer sends out a prompt through a sound signal;

Step 2. After hearing the prompt sound, the measured object stops moving, the LED light starts to flash, and the temperature measurement starts, and the single-chip microcomputer collects the voltage value of the conditioning circuit;

Step 3. In about 1 second, the temperature signal value of the measured object tends to be stable, stop the sampling work, and the measured object ends the distance is maintained;

Step 4, temperature compensation calculation, the calculation formula is: T=T ₀ +ΔT, where T is the target temperature, T ₀ is the temperature before distance compensation, and ΔT is the compensation difference;

The calculation formula of the compensation difference is: ΔT=f(l,t), where f is the compensation function, l is the distance changed by the reflective ranging switch, and t is the ambient temperature; the compensation function f uses binary linear regression, through Obtaining experimental data;

Step 5: Send the measurement results to the data acquisition device through the communication interface.

Combined with specific cases, the implementation is as follows:

As shown in Figure 2, a measured object is in a container and requires non-contact temperature measurement, and the temperature measurement device is hand-held and movable. When testing, the measuring device moves from far to near, and when a certain distance is reached, the voice prompts to keep the distance and start the temperature measurement. The LED light starts to flicker, and after a period of time, the sampling is completed, the temperature measurement device compensates and calculates in the single-chip microcomputer, and sends the measured temperature to complete the temperature measurement process.

The above descriptions are only exemplary embodiments of the present invention, and are not intended to limit the protection scope of the present invention, which is determined by the appended claims.

Claims (6)

1. a low-cost fixed-distance infrared temperature measurement method, is characterized in that, adopts infrared temperature measurement device to cooperate with distance compensation method to realize, and described infrared temperature measurement device is composed of reflective distance measurement switch, optical lens, infrared temperature measurement probe , voice prompt circuit, conditioning circuit, single-chip microcomputer, power supply, communication interface and LED indication; the optical lens focuses the infrared light emitted by the object to be measured, and projects it to the infrared temperature measuring probe, and the conditioning circuit sends out the electrical signal of the infrared temperature measuring probe. Perform conditioning, output the amplified voltage signal, and send it to the analog input port of the single-chip microcomputer; the reflective ranging switch measures whether the object is within the measurement range, and directly connects the measurement signal of the reflective ranging switch to the single-chip microcomputer, and the single-chip computer is based on the measurement signal. Perform temperature compensation according to a specific distance compensation method. In the distance compensation method, the object approaches the temperature measuring device from far to near, measures the temperature according to the signal change of the reflective distance measuring switch, and outputs the compensated temperature through the temperature compensation formula. 2. according to claim 1, it is characterised in that the specific operation steps of the distance compensation method are: Step 1. The measured object approaches the temperature measuring device from far to near. When the signal of the reflective ranging switch changes, the single-chip microcomputer sends out a prompt through a sound signal; Step 2. After hearing the prompt sound, the measured object stops moving, the LED light starts to flash, and the temperature measurement starts, and the single-chip microcomputer collects the voltage value of the conditioning circuit; Step 3. In about 1 second, the temperature signal value of the measured object tends to be stable, stop the sampling work, and the measured object ends the distance is maintained; Step 4, temperature compensation calculation, the calculation formula is: T=T ₀ +ΔT, where T is the target temperature, T ₀ is the temperature before distance compensation, and ΔT is the compensation difference; Step 5: Send the measurement results to the data acquisition device through the communication interface. 3. The method according to claim 2, wherein the calculation formula of the compensation difference is: ΔT=f(l, t), where f is the compensation function, and l is the distance changed by the reflective ranging switch , t is the ambient temperature; the compensation function f is obtained from the experimental data using bivariate linear regression. 4 . A low-cost fixed-distance infrared temperature measurement method according to claim 1 , wherein the voice prompt circuit and the LED prompt prompt the ranging process, and the power supply supplies power to the entire device. 5 . 5. A low-cost fixed-distance infrared temperature measurement device, characterized in that it is composed of a reflective distance measurement switch, an optical lens, an infrared temperature measurement probe, a sound prompt circuit, a conditioning circuit, a single-chip microcomputer, a power supply, a communication interface and an LED indication; The four parts of the optical lens, the infrared temperature measuring probe and the single-chip microcomputer are electrically connected in sequence. The reflective ranging switch, the sound prompt circuit, the communication interface and the LED indication are all electrically connected to the single-chip computer, and the power supply supplies the whole device. 6 . The low-cost fixed-distance infrared temperature measuring device according to claim 5 , wherein the voice prompt circuit and the LED prompt prompt the ranging process. 7 .

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