A device and method for determining the presence and volume of a medium using optical signals

Abstract

The present invention discloses a device and method for determining the presence and volume of a medium using an optical signal, wherein the device for determining the presence and volume of a medium using an optical signal comprises: a transparent container for accommodating the medium; an optical signal transmitting end, arranged on a first side of the transparent container, for transmitting an optical signal; an optical signal receiving end, arranged on a second side of the transparent container, for receiving the optical signal transmitted by the optical signal transmitting end; and an optical signal processing unit, for processing the optical signal received by the optical signal receiving end.

Description

Technical Field

[0001] The present invention relates to the field of detecting the presence or volume of liquid media, foam, and bubble-like media, and in particular to a device and method for determining the presence and volume of a medium using an optical signal. Background Art

[0002] With the continuous advancement of sample pretreatment and signal detection technologies, various laboratories are facing increasingly stringent requirements for medium measurement. Different processing equipment requires different testing environments, such as concentrated water baths and high-temperature environments for purge and trapping. This makes it more difficult to determine the presence and volume of a medium. Furthermore, laboratories need to use a wide variety of media with varying properties. Volatility and color, among them, can particularly impact the effectiveness of volumetric testing. Summary of the Invention

[0003] The present invention provides a device and method for determining the presence and volume of a medium using an optical signal, so as to solve the problems existing in the above-mentioned prior art.

[0004] To achieve the above-mentioned object, the present invention provides a device for determining the presence and volume of a medium using an optical signal, comprising:

[0005] a transparent container for containing a medium;

[0006] a light signal emitting end, disposed on the first side of the transparent container, for emitting a light signal;

[0007] an optical signal receiving end, disposed on the second side of the transparent container, for receiving the optical signal emitted by the optical signal emitting end; and

[0008] An optical signal processing unit is used to process the optical signal received by the optical signal receiving end.

[0009] Preferably, the transparent container is made of glass.

[0010] Preferably, the optical signal transmitting end is an infrared light source or a laser light source.

[0011] Preferably, the optical signal emitted by the optical signal transmitting end is an analog signal or a digital signal.

[0012] Preferably, the optical signal transmitting end and the optical signal receiving end are optical fiber probes.

[0013] Preferably, when the cross section of the transparent container is circular, the line connecting the optical signal emitting end and the optical signal receiving end does not pass through the center of the transparent container.

[0014] Preferably, the optical signal processing unit uses whether the level of the optical signal jumps as a basis for determining whether the medium has changed.

[0015] Preferably, the optical signal transmitting end is a circuit composed of a power supply V1, a resistor R4 and an infrared light emitting diode connected in series.

[0016] The optical signal receiving end includes a voltage source VCC, a resistor R1, a resistor R2, a resistor R3, an infrared receiving tube and a voltage comparator, wherein the resistor R2 and the infrared receiving tube are connected in series between a first end and a ground end, the resistor R1 is connected between the voltage source VCC and the first end, the resistor R3 is connected between the first end and the ground end, and the input end of the voltage comparator is connected to the first end.

[0017] Preferably, the resistance value of the resistor R1 is 10k ohms, the resistance value of the resistor R2 is 2k ohms, the resistance value of the resistor R3 is 2k ohms, the threshold level of the voltage comparator is 2.7V, the infrared light-emitting tube is IR333 / H0 / L10, and the infrared receiving tube is PT333-3B.

[0018] The present invention also provides a method for determining the presence and volume of a medium using an optical signal. This method is applied to the above-mentioned device. When the optical signal is an analog signal, the changing trend of the medium in the transparent container is determined by the following method:

[0019] S1: The optical signal processing unit continuously collects 200 data true values CurrentValue, calculates the average value PreAverage of the 200 data true values CurrentValue, and calculates the true value step CurrentN for each data true value.

[0020] S2: Count the number of each true value step, and take the true value step with the largest number as the initial step value PreN;

[0021] S3: If PreAverage < 30, then record the minimum true value step MinN = PreN, the minimum data true value MinValue = PreAverage, and then execute S5.

[0022] If PreAverage>=30, then determine whether CurrentN satisfies CurrentN<=(PreN-3). If CurrentN<=(PreN-3), then check the number of consecutive occurrences of CurrentN A. If A>=3, then determine that the decreasing trend critical point has been reached, and then execute S4.

[0023] S4: Starting from the decreasing trend critical point, continuously take 10 true data values CurrentValue and store them in the array Decrease

[10] in sequence, record the true value step corresponding to the decreasing trend critical point as MinN and the true data value MinValue, and then execute S6;

[0024] S5: If CurrentN is less than MinN, then sequentially detect the number of consecutive occurrences B of CurrentN. When B >= 3, let MinN = CurrentN and MinValue = CurrentValue, and then execute S6;

[0025] S6: Calculate the average value MinAverage of the 10 values in the array Decrease

[10] , judge the number C of data that satisfy the condition MinN < PreN. When C > 8 and MinAverage < (PreAverage - 20), it is determined that the liquid level decreasing trend appears;

[0026] S7: Sequentially judge whether the subsequent CurrentN satisfies CurrentN > MinN. When CurrentN > MinN and CurrentValue > (MinValue + 15), and the number D of consecutive CurrentValue that satisfy the above conditions is >= 5, it is determined that the rising trend critical point has been reached;

[0027] S8: Starting from the rising trend critical point, count 30 true data values, judge the number F of true data values that satisfy CurrentN >= (MinN + 1) among these 30 true data values. If F > 28, it is determined that the medium test point has been reached.

[0028] The device and method for determining the presence and volume of a medium using optical signals provided by the present invention provide an effective way to determine whether the medium exists and the volume of the medium. The beneficial technical effects are as follows:

[0029] (1) There are various types of light sources, and it is easy to use optical fiber cascading and transmission. It has high reliability, low cost, and can be widely adopted;

[0030] (2) Compared with traditional detection sensors, it has stronger anti-interference performance, wider compatibility, simple operation, extremely strong optical signal scalability, can be expanded into multiple channels using optical fiber transmission lines, and can realize single-channel or multi-channel detection systems. It is suitable for relatively harsh application environments such as high-temperature water baths, greatly reducing costs.

[0031] (3) The determination result is accurate and reliable, and it has strong operability. Users can determine the volume of various liquid media with different volatilities or colors without inputting various limiting conditions, and can also accurately determine media such as bubbles and foams in the liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 A schematic diagram of an apparatus for determining the presence and volume of a medium using an optical signal according to an embodiment of the present invention;

[0034] Figure 2 A circuit diagram of an optical signal transmitting end and an optical signal receiving end according to an embodiment of the present invention;

[0035] Figure 3a-3c Schematic diagram of the refraction of a transparent medium during the medium reduction process;

[0036] Figure 4a-4b Schematic diagram of detection of dark media;

[0037] Figure 5a This is a graph showing the value changes of the optical signal received by the receiving end during the process of medium reduction when the medium is ethanol solvent;

[0038] Figure 5b This is a graph showing the value changes of the optical signal received by the receiving end during the process of medium reduction when the medium is dichloromethane;

[0039] Figure 5c When the medium is water, the value change diagram of the optical signal receiving end during the process of medium reduction;

[0040] Figure 5d This is a graph showing the change in the value received by the optical signal receiving end during the process of medium reduction when the medium is ethyl acetate cyclohexane tea solvent;

[0041] Figure 6a This is the analog signal determination process of the present invention;

[0042] Figure 6b This is the digital signal judgment process of the present invention.

[0043] Explanation of the reference numerals: 1-transparent container; 2-optical signal transmitting end; 3-optical signal receiving end; 4-optical signal processing unit; 5-detection surface; 6-concave liquid surface; 102-infrared light-emitting tube; 103-infrared receiving tube; U1-voltage comparator; P-first end. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0045] Figure 1 FIG. 1 is a schematic diagram of a device for determining the presence and volume of a medium using an optical signal according to an embodiment of the present invention. Figure 1 As shown, the present invention provides a device for determining the presence and volume of a medium using an optical signal, comprising:

[0046] A transparent container 1 for containing a medium;

[0047] a light signal emitting end 2, disposed on a first side of the transparent container 1, for emitting a light signal;

[0048] an optical signal receiving end 3 , disposed on the second side of the transparent container 1 , for receiving the optical signal emitted by the optical signal emitting end 2 ; and

[0049] An optical signal processing unit 4 is used to process the optical signal received by the optical signal receiving end 3.

[0050] Figure 1 In the embodiment, transparent container 1 is made of, for example, glass, or other transparent materials, so that the optical signal emitted by optical signal transmitter 2 can be received by optical signal receiver 3 with minimal light loss. In the present invention, optical signal transmitter 2 is a light source, such as an infrared light source or a laser light source, although the present invention does not limit the type of light source. Alternatively, both optical signal transmitter 2 and optical signal receiver 3 may be fiber optic probes.

[0051] The optical signal transmitter 2 and the optical signal receiver 3 are placed on either side of the transparent container 1. Alternatively, depending on the actual application environment, a fiber optic probe can be placed directly on either side of the glass container in a water bath. The optical signal path between the optical signal transmitter 2 and the optical signal receiver 3 is established through optical fiber transmission, and it is not necessary to completely immerse the optical signal transmitter 2 and the optical signal receiver 3 in water. Furthermore, when routing the optical fiber, pay attention to avoiding the minimum bending radius of the optical fiber to minimize optical signal loss.

[0052] Further, Figure 1 The single-channel unit shown is easily expandable to Figure 1 It can be expanded to multiple channels and uses optical fiber transmission, which makes it more integrated and easier to expand.

[0053] In the present invention, the first side and the second side refer to the outer edges of the transparent container 1. When the cross-section of the transparent container 1 is circular, in a preferred embodiment, the line connecting the optical signal emitting end 2 and the optical signal receiving end 3 does not pass through the center of the transparent container 1. The optical signal emitting end 2, the center of the transparent container 1, and the optical signal receiving end 3 are connected in sequence, forming an angle at the center of the transparent container 1. At this time, the optical signal emitted by the optical signal emitting end 2 does not pass through the center of the transparent container 1 but reaches the optical signal receiving end 3. At this time, the optical signal received by the optical signal receiving end 3 has a greater intensity.

[0054] The optical signal processing unit 4 in the present invention may be, for example, an electronic circuit board, which controls the brightness of the optical signal emitted by the optical signal transmitting end 2 and converts the optical signal received by the optical signal receiving end 3 into an electrical signal before making a judgment.

[0055] In the present invention, the optical signal emitted by the optical signal transmitting end may be a continuous analog signal, or a digital signal represented by high and low levels.

[0056] For digital signals, "jumps" occur due to discontinuity. When a signal "jump" is detected, it is considered that the medium has changed, which can be used as a basis for judgment. For example, it can be used to determine the volume of the medium stored in a transparent container, or to determine whether the transparent container contains the medium.

[0057] For analog signals, since they are continuous, the test method can use the basic principles of statistics to determine whether the volume measurement is complete by sampling data to detect the trend of electrical signal changes during the change of the medium liquid level.

[0058] like Figure 2 FIG. 1 is a circuit diagram of an optical signal transmitting end and an optical signal receiving end according to an embodiment of the present invention. Figure 2 In the example, the optical signal transmitting end is a circuit composed of a power supply V1, a resistor R4 and an infrared light emitting tube 102 in series.

[0059] The optical signal receiving end includes a voltage source VCC, a resistor R1, a resistor R2, a resistor R3, an infrared receiving tube 103 and a voltage comparator U1, wherein the resistor R2 and the infrared receiving tube 103 are connected in series between a first terminal P and a ground terminal, the resistor R1 is connected between the voltage source VCC and the first terminal P, the resistor R3 is connected between the first terminal P and the ground terminal, and the input terminal of the voltage comparator U1 is connected to the first terminal P.

[0060] In a preferred embodiment, the parameters of each component are set as follows: the resistance value of resistor R1 is 10k ohms, the resistance value of resistor R2 is 2k ohms, the resistance value of resistor R3 is 2k ohms, the threshold level of voltage comparator U1 is 2.7V, the infrared light-emitting tube 102 is IR333 / H0 / L10, and the infrared receiving tube 103 is PT333-3B.

[0061] Figure 2 When the circuit shown is operating, infrared light-emitting diode 102 and infrared receiver diode 103 convert optical signals into electrical signals. Power supply V1 supplies power to 102 through resistor R4, acting as a light source. When infrared receiver diode 103 receives a light signal of sufficient intensity through the medium's transmission, reflection, or refraction conditions, resistor R2 is grounded. At this point, resistors R2 and R3 are connected in parallel and in series with resistor R1 to divide the voltage VCC, generating input voltage V2 for voltage comparator U1. If the light signal received by infrared receiver diode 103 is insufficient to ground resistor R2, resistor R3 is connected in series with resistor R1 to divide the voltage VCC, generating input voltage V3 for voltage comparator U1. U1's threshold level is set to 2.7V. The voltage signals of input voltages V2 and V3 are compared with the threshold level, respectively, by voltage comparator U1 to output transitional high and low level signals. In this embodiment, when the light intensity is insufficient to turn on the infrared receiving tube 103 , the output voltage of the voltage comparator U1 is 4V. When the light intensity is sufficient to turn on the infrared receiving tube 103 , the output voltage of the voltage comparator U1 is 2V.

[0062] The present invention also provides a method for determining the presence and volume of a medium using an optical signal. This method is applied to the above-mentioned device. When the optical signal is an analog signal, the changing trend of the medium in the transparent container is determined by the following method (trend determination method):

[0063] S1: The optical signal processing unit continuously collects 200 data true values CurrentValue, calculates the average value PreAverage of the 200 data true values CurrentValue, and calculates the true value step CurrentN for each data true value.

[0064] The frequency of continuous data acquisition by the optical signal processing unit is, for example, 20 Hz, and the true value step is the integer part of the quotient after the true value CurrentValue is divided by 10, that is, CurrentValue is rounded down after being divided by 10.

[0065] For example, the infrared light-emitting diode can use the laser head GYL-060105BA with a wavelength of 650nm. If the infrared receiving diode is PD333-3C, then within the wavelength range that the infrared receiving diode can receive, either infrared or laser light sources can be used as the infrared light-emitting diode. At the same time, the photosensitivity characteristics and output voltage values of the infrared receiving diode will vary.

[0066] S2: Count the number of each true value step, and take the true value step with the largest number as the initial step value PreN;

[0067] S3: If PreAverage < 30, record the smallest true value step MinN = PreN and the smallest data true value MinValue = PreAverage, then execute S5.

[0068] If PreAverage >= 30, successively determine whether CurrentN satisfies CurrentN <= (PreN - 3). When CurrentN <= (PreN - 3) is satisfied, successively detect the number of consecutive occurrences A of CurrentN. When A >= 3 appears, it is determined that the decreasing trend critical point has been reached, and then execute S4.

[0069] If PreAverage is lower than 30, it is considered that the transparent container 1 contains a dark liquid medium with very low light transmittance, otherwise it is determined to be a light liquid medium.

[0070] S4: Starting from the decreasing trend critical point, continuously take 10 data true values CurrentValue and store them in the array Decrease

[10] in sequence, and record the true value step corresponding to the decreasing trend critical point as MinN and the data true value MinValue, then execute S6.

[0071] S5: If CurrentN is less than MinN, successively detect the number of consecutive occurrences B of CurrentN. When B >= 3 appears, let MinN = CurrentN and MinValue = CurrentValue, then execute S6.

[0072] S6: Calculate the average value MinAverage of the 10 values in the array Decrease

[10] , and judge the number C of data true values that satisfy the condition MinN < PreN. When C > 8 and MinAverage < (PreAverage - 20), it is determined that the liquid level decreasing trend appears.

[0073] S7: Successively judge whether the subsequent CurrentN satisfies CurrentN > MinN. When CurrentN > MinN and CurrentValue > (MinValue + 15) are satisfied, and the number D of consecutive CurrentValue that satisfy the above conditions is >= 5, it is determined that the increasing trend critical point has been reached.

[0074] S8: Start counting 30 data true values from the increasing trend critical point, and judge the number F of data true values that satisfy CurrentN >= (MinN + 1) among these 30 data true values. If F > 28, it is determined that the medium test point has been reached.

[0075] The above method is further explained as follows:

[0076] Figure 3a-3c This is a schematic diagram of the refraction of the transparent medium in the liquid level during the medium reduction process. Figure 3a The diagram shows the detection surface 5 and the concave liquid surface 6. The detection surface 5 is fixed, while the concave liquid surface 6 descends as the liquid decreases. Initially, the optical signal transmitter 2 is in close contact with the wall of the transparent container 1. The optical signal is received by 103 through the wall and the internal medium and processed into an electrical signal. Because the optical signal is emitted vertically onto the side wall 101, it directly penetrates and is received by the optical signal receiver 3, with negligible loss. As the medium in the transparent container 1 gradually decreases, the optical signal is refracted when the concave liquid surface 6 reaches the detection surface 5. This reduces the light intensity received by the optical signal receiver, resulting in a lower detection value. When the concave liquid surface 6 drops below the detection surface 5, the optical signal is refracted only between the wall and the air, without any refraction from the liquid surface. Consequently, the optical signal is refracted less, and the optical signal receiver receives more light, increasing the detection value.

[0077] The critical point of the decreasing trend is when the concave liquid surface 6 just touches the detection surface 5, showing a decreasing value.

[0078] When the light intensity rises, most of the concave liquid surface 6 falls below the detection surface 5, and the received light intensity recovers and gradually increases.

[0079] For dark media, as shown in FIG4 , the concave liquid surface 6 is above the detection surface 5 , and the color of the medium absorbs a large portion of the light, causing the optical signal receiving end to receive weak light. When the concave liquid surface 6 drops below the detection surface 5 , the light signal directly incident from the optical signal transmitting end 2 to the optical signal receiving end 3 is enhanced.

[0080] "CurrentN appears a number of times in a row. If A >= 3 times, it is determined that the critical point of the decreasing trend has been reached." This step is designed because during operation, especially in a water bath, there may be a lot of bubble interference. If one or two values occasionally decrease, it should not be assumed that the concave meniscus has reached the detection surface. To eliminate interference, the number of consecutive occurrences of the current value at the same step is continuously recorded when determining the trend or trend critical point, thereby improving judgment accuracy.

[0081] Figure 6a This is an analog signal determination process according to an embodiment of the present invention. Figure 6b This is a digital signal determination process according to an embodiment of the present invention, which respectively presents determination processes when the optical signal transmitted by the optical signal transmitting end is an analog signal or a digital signal.

[0082] Figure 5a-5d A diagram showing the changes in the values received by the optical signal receiving end during the medium reduction process for four different media, where the horizontal axis is time.

[0083] The device and method for determining the presence and volume of a medium using an optical signal provided by the present invention provide an effective way to determine the presence and volume of a medium, and the beneficial technical effects are as follows:

[0084] (1) There are various light sources, which are easy to cascade and transmit using optical fibers, are highly reliable, inexpensive, and can be widely adopted;

[0085] (2) Compared with traditional detection sensors, it has stronger anti-interference performance, wider compatibility, simpler operation, and strong scalability of optical signals. It can be expanded into multiple channels using optical fiber transmission lines to realize single-channel or multi-channel detection systems. It is suitable for relatively harsh application environments such as water baths and high temperatures, greatly reducing costs.

[0086] (3) The determination results are accurate and reliable, and the operability is strong. Users do not need to enter various restrictions to be compatible with the determination of the volume of various liquid media with different volatility or colors. At the same time, it can also accurately determine media such as bubbles and foam in the liquid.

[0087] Those skilled in the art will appreciate that the accompanying drawings are merely schematic diagrams of an embodiment, and the modules or processes in the accompanying drawings are not necessarily required to implement the present invention.

[0088] Those skilled in the art will appreciate that the modules in the apparatuses of the embodiments may be distributed in the apparatuses of the embodiments as described in the embodiments, or may be located in one or more apparatuses different from the embodiments with corresponding changes. The modules in the above embodiments may be combined into one module or further divided into multiple sub-modules.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the presence and volume of a medium using an optical signal, the method being applied to a device for determining the presence and volume of a medium using an optical signal, the device comprising a transparent container, an optical signal transmitting end, an optical signal receiving end, and an optical signal processing unit, wherein the transparent container is used to accommodate the medium; the optical signal transmitting end is provided on a first side of the transparent container and is used to transmit an optical signal; the optical signal receiving end is provided on a second side of the transparent container and is used to receive an optical signal transmitted by the optical signal transmitting end; the optical signal processing unit is used to process an optical signal received by the optical signal receiving end, and is characterized in that: When the optical signal is an analog signal, the following method is used to determine the change trend of the medium in the transparent container: S1: The optical signal processing unit continuously collects 200 data true values CurrentValue, calculates the average value PreAverage of the 200 data true values CurrentValue, and calculates the true value step CurrentN for each data true value. S2: Count the number of each true value step, and take the true value step with the largest number as the initial step value PreN; S3: If PreAverage < 30, record the smallest true value step MinN = PreN, the smallest data true value MinValue = PreAverage, and then execute S5. If PreAverage >= 30, then sequentially determine whether CurrentN satisfies CurrentN <= (PreN - 3). When CurrentN <= (PreN - 3) is satisfied, sequentially detect the number of consecutive occurrences A of CurrentN. When A >= 3 appears, it is determined that the decreasing trend critical point has been reached, and then execute S4; S4: Starting from the decreasing trend critical point, continuously take 10 data true values CurrentValue and store them in the array Decrease[10] in sequence, and record the true value step corresponding to the decreasing trend critical point as MinN and the data true value MinValue, and then execute S6; S5: If CurrentN is less than MinN, sequentially detect the number of consecutive occurrences B of CurrentN. When B >= 3 appears, let MinN = CurrentN and MinValue = CurrentValue, and then execute S6; S6: Calculate the average value MinAverage of the 10 values in the array Decrease[10], and judge the number C of data that satisfy the condition MinN < PreN. When C > 8 and MinAverage < (PreAverage - 20), it is determined that the liquid level decreasing trend appears; S7: Sequentially judge whether the subsequent CurrentN satisfies CurrentN > MinN. When CurrentN > MinN and CurrentValue > (MinValue + 15) are satisfied, and the number D of consecutive CurrentValue that satisfy the above conditions is D >= 5, it is determined that the increasing trend critical point has been reached; S8: Start counting 30 data true values from the increasing trend critical point, and judge the number F of data true values that satisfy CurrentN >= (MinN + 1) among these 30 data true values. If F > 28, it is determined that the medium test point has been reached.

2. The method for determining the presence and volume of a medium using an optical signal according to claim 1, wherein: The material of the transparent container is glass.

3. The method for determining the presence and volume of a medium using an optical signal according to claim 1, wherein: The optical signal transmitting end is an infrared light source or a laser light source.

4. The method for determining the presence and volume of a medium using an optical signal according to claim 1, wherein: The optical signal transmitted by the optical signal transmitting end is an analog signal or a digital signal.

5. The method for determining the presence and volume of a medium using an optical signal according to claim 1, wherein: The optical signal transmitting end and the optical signal receiving end are fiber optic probes.

6. The method for determining the presence and volume of a medium using an optical signal according to claim 1, wherein: When the cross-section of the transparent container is circular, the connection line between the optical signal transmitting end and the optical signal receiving end does not pass through the center of the transparent container.

7. The method for determining the presence and volume of a medium using an optical signal according to claim 1, wherein: The optical signal processing unit uses whether the level of the optical signal jumps as the basis for the change of the medium.

8. The method for determining the presence and volume of a medium using an optical signal according to claim 1, wherein: The optical signal transmitting end is a circuit composed of a power supply V1, a resistor R4, and an infrared light-emitting diode connected in series. The optical signal receiving end includes a voltage source VCC, a resistor R1, a resistor R2, a resistor R3, an infrared receiving tube and a voltage comparator, wherein the resistor R2 and the infrared receiving tube are connected in series between a first end and a ground end, the resistor R1 is connected between the voltage source VCC and the first end, the resistor R3 is connected between the first end and the ground end, and the input end of the voltage comparator is connected to the first end.

9. The method for determining the presence and volume of a medium using an optical signal according to claim 8, wherein: The resistance value of the resistor R1 is 10k ohms, the resistance value of the resistor R2 is 2k ohms, the resistance value of the resistor R3 is 2k ohms, the threshold level of the voltage comparator is 2.7V, the infrared light emitting tube is IR333 / H0 / L10, and the infrared receiving tube is PT333-3B.

Images