Gesture sensing circuit with adjustable sensing distance, range hood and control method

Abstract

This invention discloses a gesture sensing circuit with adjustable sensing distance, a range hood, and a control method. In this gesture sensing circuit, the infrared emitting circuit includes a first current regulating unit connected in series with an infrared emitting unit and a switching unit. The first current regulating unit includes at least two current regulating branches with different resistances, and each current regulating branch is connected one-to-one to the power supply voltage output terminals of the microprocessor. The microprocessor selects the current regulating branch to supply power, selects the current regulating branch connected in series with the infrared emitting unit and the switching unit, controls the conduction current of the series path, and changes the carrier signal strength of the infrared emitting unit. This invention solves the problem that the fixed detection range of existing gesture sensing circuits cannot adapt to complex user environments. It allows for flexible adjustment of the sensing distance within a larger adjustment range, meeting the actual gesture control needs of users and improving the user experience.

Description

Technical Field

[0001] This invention relates to the field of smart home technology, and in particular to a gesture sensing circuit with adjustable sensing distance, a range hood, and a control method. Background Technology

[0002] With the development of technology, the control methods for range hoods have become increasingly diverse, and range hoods with gesture sensing functions have become widely popular in the market. When cooking, users' hands are often covered in grease, making it inconvenient to control the range hood by clicking on the control panel or using a mobile app. However, with gesture sensing, users can adjust the range hood's operating mode remotely by simply waving their hands, without touching the hood.

[0003] However, the gesture sensing function of current range hoods on the market has two problems: First, gesture sensing functions are mostly limited to a fixed range (the maximum sensing distance is usually 15-30cm), while actual cooking scenarios are much more complex. Different types of kitchens, user heights, and cooking habits all affect the actual gesture sensing distance during cooking. Relying on a fixed gesture sensing range cannot provide users with the best experience. Second, gesture sensing has weak anti-interference capabilities. On the one hand, the gesture sensing module is easily affected by infrared light in the environment; on the other hand, the gesture sensing function can easily be accidentally triggered by users during cooking, affecting the user experience. Summary of the Invention

[0004] This invention provides a gesture sensing circuit, a range hood, and a control method with adjustable sensing distance, so as to realize the adjustable range of gesture sensing distance. The sensing distance can be flexibly adjusted within a large adjustment range to meet the actual gesture control needs of users and improve the user experience.

[0005] In a first aspect, embodiments of the present invention provide a gesture sensing circuit with adjustable sensing distance, including a microprocessor, an infrared emitting circuit, and an infrared receiving circuit; The microprocessor includes a sensing signal input terminal, a first control signal output terminal, and at least two power supply voltage output terminals; The infrared emitting circuit includes a first current regulating unit, an infrared emitting unit, and a switching unit; the first current regulating unit includes at least two current regulating branches, each with a different resistance; one end of each of the at least two current regulating branches is electrically connected to at least two power supply voltage output terminals, and the other end of each branch is electrically connected to the first node; the infrared emitting unit and the switching unit are connected in series between the first node and the fixed potential node; the first control signal output terminal is electrically connected to the control terminal of the switching unit. The microprocessor is configured to output a first pulse width modulation signal with a first preset frequency through a first control signal output terminal to control the switching unit to turn on and off according to the first preset frequency, and the infrared emitting unit to emit light and turn off according to the first preset frequency, and to emit a carrier signal with the first preset frequency. The microprocessor is also configured to provide a power supply voltage to at least one power supply voltage output terminal; the microprocessor has multiple sensing distance modes, in which the power supply voltage output terminal provided by the microprocessor is different and the current passing through the infrared emitting unit is different, so that the carrier signal has different transmission intensities. The infrared receiving circuit is configured to detect a carrier signal of a first preset frequency, generate an induction signal, and provide it to the microprocessor through the induction signal input terminal; The microprocessor is also configured to determine, based on the sensing signal, whether there is an object within the detection range corresponding to the current sensing distance mode.

[0006] Optionally, the first current regulating unit includes a resistor, and the resistance value of the resistor in different first current regulating units is different.

[0007] Optionally, the first current regulating unit also includes an indicator light, wherein the indicator light and the resistor in the same first current regulating unit are connected in series, and the indicator lights in different first current regulating units emit different colors.

[0008] Optionally, the switching unit includes a transistor; the base of the transistor is electrically connected to the first control signal output terminal, the collector of the transistor is electrically connected to the infrared emitting unit, and the emitter of the transistor is electrically connected to the fixed potential node.

[0009] Optionally, the microprocessor also includes a second control signal output terminal; The infrared emitting circuit also includes a second current adjustment unit, which is connected between the fixed potential node and the ground terminal; The microprocessor is also configured to output a second pulse width modulation signal to the second current adjustment unit via the second control signal output terminal to change the potential of the fixed potential node and adjust the current passing through the infrared emitting unit so that the carrier signal has different emission intensities.

[0010] Optionally, the second current regulation unit includes a voltage divider resistor and a voltage regulator capacitor, which are connected in parallel between the fixed potential node and the ground terminal; the second control signal output terminal is electrically connected to the fixed potential node.

[0011] Optionally, the infrared receiving circuit includes an infrared receiving chip, and the output terminal of the infrared receiving chip is electrically connected to the sensing signal input terminal; The infrared receiver chip is configured to receive a reflected carrier signal of a first preset frequency, and output a first-level voltage signal as an induction signal when the carrier signal of the first preset frequency is received, and output a second-level voltage signal as an induction signal when the carrier signal of the first preset frequency is not received, wherein the voltage levels of the first-level voltage signal and the second-level voltage signal are different.

[0012] Secondly, embodiments of the present invention also provide a range hood, characterized in that it includes a gesture detection module, the gesture detection module including at least two sets of gesture sensing circuits with adjustable sensing distance as described in any of the first aspects; the gesture detection module is used to perform gesture detection operations to determine the user's gesture actions.

[0013] Thirdly, embodiments of the present invention also provide a control method for a range hood, characterized in that it is applied to a range hood in a second direction, and the control method includes: Using a gesture detection module, gesture detection operations are performed repeatedly within a preset sensing distance until the cooking process ends; When a gesture is detected, the preset operation of the range hood corresponding to the gesture is executed.

[0014] Optionally, it also includes: Real-time acquisition of preset sensing distance.

[0015] Optionally, it also includes: When no gesture is detected, the preset sensing distance is adjusted based on the detection results.

[0016] Optionally, when no gesture is detected, the preset sensing distance is adjusted according to the detection status, including: When an object is detected for a first preset time, the preset sensing distance is reduced according to a preset adjustment range. If no object is detected for a second preset time, the preset sensing distance is increased according to the preset adjustment range.

[0017] Optionally, the first preset time is t1, and the second preset time is t2, where t1 < t2.

[0018] Optionally, the distance between the user's body and palm is L, and the preset adjustment range is d; where d = k × L, 0 < k ≤ 1.

[0019] The technical solution of this invention, by setting a first current adjustment unit connected in series with the infrared emitting unit and the switching unit in the infrared emitting circuit, includes at least two current adjustment branches with different resistances. Each current adjustment branch is connected one-to-one with the power supply voltage output terminals of the microprocessor. The microprocessor selects the current adjustment branch to supply power, selects the current adjustment branch connected in series with the infrared emitting unit and the switching unit, controls the conduction current of the series path, and changes the carrier signal strength of the infrared emitting unit, thereby realizing the adjustment of the detection distance of the gesture sensing circuit. This invention solves the problem that the detection range of existing gesture sensing circuits is fixed and cannot adapt to the complex user environment. It allows for flexible adjustment of the sensing distance within a larger adjustment range, meeting the actual gesture control needs of users and improving the user experience. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a gesture sensing circuit with adjustable sensing distance provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of another gesture sensing circuit with adjustable sensing distance provided in an embodiment of the present invention; Figure 3 and Figure 4 This is a schematic diagram of the structure of two more gesture sensing circuits with adjustable sensing distance provided in the embodiments of the present invention; Figure 5 This is a flowchart of a control method for a range hood provided in an embodiment of the present invention; Figure 6 This is a flowchart of another control method for a range hood provided in an embodiment of the present invention; Figure 7 This is a flowchart of another control method for a range hood provided in an embodiment of the present invention.

[0021] In the picture: 10 - Microprocessor, 20 - Infrared transmitting circuit, 21 - First current regulating unit, 210 - Current regulating branch, 211 - First current regulating branch, 212 - Second current regulating branch, 213 - Third current regulating branch, 22 - Infrared transmitting unit, 23 - Switching unit, 24 - Second current regulating unit, 30 - Infrared receiving circuit. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0023] The terminology used in the embodiments of this invention is for the purpose of describing specific embodiments only and is not intended to limit the invention. It should be noted that directional terms such as "upper," "lower," "left," and "right" described in the embodiments of this invention are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when referring to an element being formed "on" or "below" another element, it can be formed not only directly on or below the other element, but also indirectly on or below it through intermediate elements. The terms "first," "second," etc., are used for descriptive purposes only and do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0024] The term "comprising" and its variations as used in this invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment".

[0025] It should be noted that the concepts of "first" and "second" mentioned in this invention are only used to distinguish the corresponding contents and are not used to limit the order or interdependence.

[0026] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0027] Figure 1 This is a schematic diagram of a gesture sensing circuit with adjustable sensing distance provided in an embodiment of the present invention. (Refer to...) Figure 1 The gesture sensing circuit includes a microprocessor 10, an infrared emitting circuit 20, and an infrared receiving circuit 30. The microprocessor 10 includes a sensing signal input terminal Out_signal, a first control signal output terminal PWM_1, and at least two power supply voltage output terminals IO. The infrared emitting circuit 20 includes a first current regulating unit 21, an infrared emitting unit 22, and a switching unit 23. The first current regulating unit 21 includes at least two current regulating branches 210, each with a different resistance. One end of each of the at least two current regulating branches 210 is electrically connected to one of the at least two power supply voltage output terminals IO, and the other end of each branch is electrically connected to a first node N1. The infrared emitting unit 22 and the switching unit 23 are connected in series between the first node N1 and a fixed potential node N0. The first control signal output terminal PWM_1 is electrically connected to the control terminal of the switching unit 23.

[0028] The microprocessor 10 is configured to output a first pulse width modulation signal with a first preset frequency through a first control signal output terminal PWM_1, to control the switching unit 23 to turn on and off according to the first preset frequency, and the infrared emitting unit 22 to emit light and extinguish according to the first preset frequency, emitting a carrier signal with the first preset frequency. The microprocessor 10 is also configured to provide a power supply voltage to at least one power supply voltage output terminal IO; the microprocessor 10 has multiple sensing distance modes, and in different sensing distance modes, the power supply voltage output terminal IO provided by the microprocessor 10 is different, and the current passing through the infrared emitting unit 22 is different, so that the carrier signal has different transmission intensities. The infrared receiving circuit 30 is configured to detect the carrier signal of the first preset frequency, generate a sensing signal, and provide it to the microprocessor 10 through the sensing signal input terminal Out_signal. The microprocessor 10 is also configured to determine whether an object exists within the detection range corresponding to the current sensing distance mode based on the sensing signal.

[0029] First, those skilled in the art will understand that this gesture sensing circuit determines whether a user's arm is present within its detection range based on whether an object exists within the target area. Building upon this, multiple gesture sensing circuits are arranged in a reasonable manner, such as sequentially. These multiple circuits sense whether a user's arm is present within their respective detection areas. Then, based on the time sequence and frequency of the multiple gesture sensing circuits detecting the user's arm, gestures such as left swipes and right swipes made by the user's arm in each detection area of ​​the multiple gesture sensing circuits can be determined, thus achieving gesture detection.

[0030] For a single gesture sensing circuit, its main function is simply to detect the presence of an object within the target range. The microprocessor 10 controls the infrared emitting circuit 20 to emit an infrared carrier signal of a specific frequency, while the infrared receiving circuit 30 can identify the reflected signal of this carrier signal after it has been reflected by an obstacle. In the infrared emitting circuit 20, the infrared emitting unit 22 and the switching unit 23 are connected in series. The infrared emitting unit 22 can specifically be an infrared light-emitting diode D1. When the switching unit 23 is turned on, the infrared emitting unit 22 carries current, thereby emitting an infrared light signal. The conduction frequency of the switching unit 23 determines the frequency at which the infrared emitting unit 22 emits the infrared light signal, thus generating a carrier signal of a specific frequency. Therefore, by electrically connecting the control terminal of the switching unit 23 to the first control signal output terminal PWM_1 of the microprocessor 10, the microprocessor 10 outputs a first pulse width modulation signal with a first preset frequency through the first control signal output terminal PWM_1. This allows the microprocessor 10 to control the switching unit 23 to turn on and off according to the first preset frequency. At this time, the infrared emitting unit 22 can emit light and extinguish at the first preset frequency, emitting a carrier signal with the first preset frequency.

[0031] Furthermore, it can be understood that the strength of the carrier signal emitted by the infrared emitting unit 22 determines the detection distance of the gesture sensing circuit: when the carrier signal is strong, the reflected signal reflected back from a distant obstacle is also strong, so it can be received by the infrared receiving circuit 30, realizing the sensing of objects at a greater distance; when the carrier signal is weak, the reflected signal reflected back from a distant obstacle is weak, so it cannot be received by the infrared receiving circuit 30, and cannot effectively sense objects at a greater distance. Therefore, in this embodiment of the invention, a first current adjustment unit 21 connected in series with the infrared emitting unit 22 and the switching unit 23 is added to the infrared emitting circuit 20. The first current adjustment unit 21 includes at least two current adjustment branches 210, and the current limiting resistors of each current adjustment branch 210 are different. At the same time, each current adjustment branch 210 is electrically connected to each power supply voltage output terminal IO of the microprocessor 10 in a one-to-one correspondence, indicating that the power supply of each current adjustment branch 210 is selected by the microprocessor 10. The microprocessor 10 selects the current adjustment branch 210 connected in series with the infrared emitting unit 22 and the switching unit 23 to change the resistance of the entire series path, thereby adjusting the conduction current of the entire series path. The conduction current of the infrared emitting unit 22 determines the intensity of the infrared light signal emitted by it, thereby controlling the carrier intensity emitted by the infrared emitting unit 22 and realizing the purpose of adjusting the detection distance of the gesture sensing circuit. Existing gesture sensing circuits with fixed detection ranges either have too short a detection distance, making long-distance operation inconvenient, or too large a detection distance, leading to oversensitivity, increased likelihood of accidental triggering, and greater susceptibility to interference from ambient light, resulting in a poor overall user experience and difficulty in meeting the needs of users in complex environments. In contrast, the gesture sensing circuit of this invention allows for flexible adjustment of the sensing distance, ensuring a wider range of adjustment to meet the needs of users in complex environments and improve the user experience.

[0032] The technical solution of the above embodiment, by setting a first current adjustment unit connected in series with the infrared emitting unit and the switching unit in the infrared emitting circuit, includes at least two current adjustment branches with different resistances. Each current adjustment branch is connected one-to-one with each power supply voltage output terminal of the microprocessor. The microprocessor selects the current adjustment branch to be powered, selects the current adjustment branch connected in series with the infrared emitting unit and the switching unit, controls the conduction current of the series path, and changes the carrier signal strength of the infrared emitting unit, thereby realizing the adjustment of the detection distance of the gesture sensing circuit. This embodiment of the invention solves the problem that the detection range of existing gesture sensing circuits is fixed and cannot adapt to the complex user environment. It allows for flexible adjustment of the sensing distance within a larger adjustment range, meeting the actual gesture control needs of users and improving the user experience.

[0033] Continue to refer to Figure 1In one optional embodiment, the current regulating branch 210 includes a resistor, and the resistance values ​​of the resistors in different current regulating branches 210 are different.

[0034] Specifically, such as Figure 1 In the example, the first current adjustment unit 21 can be provided with three current adjustment branches 210, namely the first current adjustment branch 211, the second current adjustment branch 212, and the third current adjustment branch 213. The resistors in the three current adjustment branches 210 are respectively the first resistor R1, the second resistor R2, and the third resistor R3, and the resistance values ​​of the three resistors are different. Correspondingly, the microprocessor 10 includes three power supply voltage output terminals IO, namely the first power supply voltage output terminal IO1, the second power supply voltage output terminal IO2, and the third power supply voltage output terminal IO3, and the three power supply voltage output terminals IO are respectively connected to one end of the first resistor R1, the second resistor R2, and the third resistor R3.

[0035] Continue to refer to Figure 1 In an optional embodiment, the switching unit 23 includes a transistor Q1; the base of transistor Q1 is electrically connected to the first control signal output terminal PWM_1, the collector of transistor Q1 is electrically connected to the infrared emitting unit 22, and the emitter of transistor Q1 is electrically connected to the fixed potential node N0.

[0036] It should be added that, in this embodiment, the fixed potential node N0 connected to the emitter of transistor Q1 can specifically be a ground terminal, providing a fixed ground potential. The base of transistor Q1 is connected to the second node N2, and the second node N2 is electrically connected to the first control signal output terminal PWM_1 of microprocessor 10 through the fourth resistor R4, and is also grounded through the fifth resistor R5.

[0037] Figure 2 This is a schematic diagram of another adjustable-distance gesture sensing circuit provided in an embodiment of the present invention, for reference. Figure 2 In an optional embodiment, the current regulating branch 210 further includes an indicator light, wherein the indicator light and the resistor in the same current regulating branch 210 are connected in series, and the indicator lights in different current regulating branches 210 emit different colors.

[0038] As in the previous example, the first current regulating branch 211, the second current regulating branch 212 and the third current regulating branch 213 can be respectively equipped with a first indicator light L1, a second indicator light L2 and a third indicator light L3. These three indicator lights have different light emission colors, such as red, yellow and green.

[0039] Figure 3 and Figure 4 This is a schematic diagram of two more gesture sensing circuits with adjustable sensing distance provided in the embodiments of the present invention. (Refer to...) Figure 3 and Figure 4 In another embodiment of the present invention, the microprocessor 10 further includes a second control signal output terminal PWM_2; the infrared emitting circuit 20 further includes a second current adjustment unit 24, which is connected between the fixed potential node N0 and the ground terminal. The microprocessor 10 is also configured to output a second pulse width modulation signal to the second current adjustment unit 24 through the second control signal output terminal PWM_2 to change the potential of the fixed potential node N0 and adjust the current passing through the infrared emitting unit 22 so that the carrier signal has different emission intensities.

[0040] Specifically, the second current regulation unit 24 includes a voltage divider resistor R6 and a voltage regulator capacitor C1, which are connected in parallel between the fixed potential node N0 and the ground terminal; the second control signal output terminal PWM_2 is electrically connected to the fixed potential node N0.

[0041] The following is based on Figure 3 Taking an example, the specific working principle of the two current regulation units in this embodiment of the invention will be briefly described. First, the first control signal output terminal PWM_1 of the microprocessor 10 outputs a first pulse width modulation signal with a first preset frequency, thereby controlling the transistor Q1 to conduct intermittently at the first preset frequency, thereby causing the infrared emitting diode to flash at the first preset frequency and emit a carrier signal of the first preset frequency. For the infrared emitting diode, its conduction current determines the strength of its emitted carrier signal. In the series circuit where the infrared emitting diode is located, the current I of the infrared emitting diode is... D For: I D =(V i -V D -V6) / R. Where R represents the resistance of the current-regulating branch 210 connected in series with the infrared emitting diode and transistor Q1, and V is the voltage across the infrared emitting diode D1. D The power supply voltage Vi provided by the power supply voltage output terminal IO of the microprocessor 10 remains unchanged. Therefore, the current of the infrared emitting diode depends only on the voltage V6 of the fixed potential node N0 and the resistance R of the current regulating branch 210 connected in series with the infrared emitting diode and the transistor Q1.

[0042] Based on this, in this embodiment of the invention, the microprocessor 10 can control any one of the three power supply voltage output terminals IO to provide a power supply voltage. When the first power supply voltage output terminal IO1 provides a power supply voltage, while the second power supply voltage output terminal IO2 and the third power supply voltage output terminal IO3 are off, it indicates that the first resistor R1 is connected in series with the infrared light-emitting diode D1 and the transistor Q1. At this time, the current I of the infrared light-emitting diode D1 is... D For: I D =(V i -V D-V6) / R1. When the power supply voltage is switched to the second power supply voltage output terminal IO2, while the first power supply voltage output terminal IO1 and the third power supply voltage output terminal IO3 are turned off, it means that the second resistor R2 is connected in series with the infrared LED D1 and the transistor Q1. At this time, the current I of the infrared LED D1 is... D For: I D =(V i -V D -V6) / R2. Similarly, when the power supply voltage is switched to the third power supply voltage output terminal IO3, while the first power supply voltage output terminal IO1 and the second power supply voltage output terminal IO2 are closed, it means that the third resistor R3 is connected in series with the infrared LED D1 and the transistor Q1. At this time, the current I of the infrared LED D1 is... D For: I D =(V i -V D -V6) / R3. It can be seen that by switching the power supply voltage output terminal IO, the current of the infrared LED D1 can be changed, controlling the transmission intensity of the carrier signal and thus adjusting the sensing distance. Furthermore, by appropriately setting the resistance values ​​of the first resistor R1, the second resistor R2, and the third resistor R3, the gesture sensing range can be gradually increased when switching to different power supply voltage output terminals IO. For example, the resistance values ​​of the first resistor R1, the second resistor R2, and the third resistor R3 can be set to decrease sequentially, corresponding to a gesture sensing range of 2-30cm when the first power supply voltage output terminal IO1 provides power, 2-40cm when the second power supply voltage output terminal IO2 provides power, and 2-50cm when the third power supply voltage output terminal IO3 provides power.

[0043] Simultaneously, the second pulse width modulation signal is output through the second control signal output terminal PWM_2 of the microprocessor 10, which can charge and discharge the voltage regulator capacitor C1, thereby maintaining the voltage of the voltage divider resistor R6 and keeping the voltage of the fixed potential node N0 fixed. When the duty cycle and frequency of the second pulse width modulation signal are changed, the voltage divider resistor R6 can be made to have different voltage divisions, and the voltage of the fixed potential node N0 changes. This can also change the current I of the infrared emitting diode. DThis allows for adjustment of the carrier signal strength. It's understood that adjusting the carrier signal transmission strength via the second pulse width modulation signal primarily involves fine-tuning the sensing distance based on a selected power supply voltage output terminal IO, creating a large adjustable range. Therefore, this embodiment provides both a wider and more precise sensing distance adjustment range, offering users diverse options and better meeting complex usage scenarios. If the user doesn't require a long gesture sensing distance, they can choose to supply power to the first resistor R1 with a larger resistance, allowing for further fine-tuning within a 2-30cm gesture sensing range. If the user requires a larger gesture sensing distance, they can choose to supply power to the third resistor R3 with a smaller resistance, allowing for further selection of the desired gesture sensing distance within a 2-50cm range, although the adjustment precision will be reduced in this case.

[0044] It would also like to add that the power supply voltage output terminals IO of the microprocessor 10 are not limited to supplying power to only one port; they can also supply power to two or more ports simultaneously. Therefore, for the three power supply voltage output terminals IO, there are seven possible combinations, i.e., seven possible sensing ranges. Specifically, as mentioned earlier, when each power supply voltage output terminal IO is supplied individually, three sensing ranges can be obtained. Similarly, when two power supply voltage output terminals IO are supplied simultaneously, there are three possible combinations, also corresponding to three sensing ranges. For example, when the first power supply voltage output terminal IO1 and the second power supply voltage output terminal IO2 are supplied together, the first resistor R1 and the second resistor R2 are connected in parallel and connected in series with the infrared LED D1 and the transistor Q1. At this time, the current I of the infrared LED D1... D For: I D =(V i -V D -V6) / R1+(V i -V D -V6) / R2. At this time, the upper limit of the gesture sensing range becomes the combined value: 30cm + 40cm = 70cm, that is, the sensing range in this case is 2-70cm. When the first power supply voltage output terminal IO1 and the third power supply voltage output terminal IO3 are powered together, the first resistor R1 and the third resistor R3 are connected in parallel, and connected in series with the infrared LED D1 and the transistor Q1. At this time, the current I of the infrared LED D1 is... D For: I D =(V i -V D -V6) / R1+(V i -V D-V6) / R3. At this time, the upper limit of the gesture sensing range becomes the combined value: 30cm + 50cm = 80cm, that is, the sensing range in this case is 2-80cm. When the second power supply voltage output terminal IO2 and the third power supply voltage output terminal IO3 are powered together, the second resistor R2 and the third resistor R3 are connected in parallel, and connected in series with the infrared LED D1 and the transistor Q1. At this time, the current I of the infrared LED D1 is... D For: I D =(V i -V D -V6) / R2+(V i -V D -V6) / R3. At this point, the upper limit of the gesture sensing range becomes a combined value: 40cm + 50cm = 90cm, meaning the sensing range in this case is 2-90cm. Alternatively, all three power supply voltage output terminals IO can be powered simultaneously, achieving the same sensing range. When the first power supply voltage output terminal IO1, the second power supply voltage output terminal IO2, and the third power supply voltage output terminal IO3 are powered simultaneously, the first resistor R1, the second resistor R2, and the third resistor R3 are connected in parallel and in series with the infrared LED D1 and the transistor Q1. At this time, the current I of the infrared LED D1... D For: I D =(V i -V D -V6) / R1+(V i -V D -V6) / R2+(V i -V D -V6) / R3. At this point, the upper limit of the gesture sensing range becomes a combined value: 30cm + 40cm + 50cm = 120cm, meaning the sensing range in this case is 2-120cm. As can be seen above, when the microprocessor 10 is configured with three power supply voltage output terminals (IO), seven different combinations can be formed, resulting in seven different gesture sensing ranges. In practical applications, this invention is not limited to three power supply voltage output terminals (IO). The system can achieve more combinations by setting more power supply voltage output terminals, thereby making the adjustable range larger and more precise.

[0045] and Figure 1 and Figure 3 compared to, Figure 2 and Figure 4In the illustrated embodiment, an indicator light is added to the current regulation branch 210. When the power supply voltage output terminal IO of the microprocessor 10 is powered, the corresponding current regulation branch 210 is turned on, and the indicator light on it illuminates. This provides a notification to the user, allowing them to know the status of the currently activated power supply voltage output terminal IO, and thus indirectly understand the distance range of the gesture sensing. For example, if the first indicator light L1, the second indicator light L2, and the third indicator light L3 are set to emit red, yellow, and green light respectively, then when the first power supply voltage output terminal IO1 is powered, the first indicator light L1 will illuminate, and the user will see a red light emanating from the vicinity of the gesture sensing circuit, indicating that the current sensing distance of the gesture sensing module is within the range of 2-30cm. When the second power supply voltage output terminal IO2 is powered, the second indicator light L2 will illuminate, and the user will see a yellow light emanating from the vicinity of the gesture sensing circuit, indicating that the current sensing distance of the gesture sensing module is within the range of 2-40cm. When the third power supply voltage output terminal IO3 is powered, the third indicator light L3 will light up. The user can see that the gesture sensing circuit emits green light at this time, which means that the current sensing distance of the gesture sensing module is in the range of 2-50cm.

[0046] Additionally, it should be noted that when the indicator light is connected in series in the current regulating branch 210, the current I of the infrared emitting diode... D It becomes: I D =(V i -V D -V6-V L ) / R, where V L This refers to the voltage drop across the indicator light. Since the voltage drop across the indicator lights in each current regulation branch 210 is the same, the voltage drop across the indicator light has no effect on the current of the infrared LED D1 when selecting and switching power supply via the power supply voltage output terminal IO; it depends only on the value of the series resistor.

[0047] Continue to refer to Figures 1-4 Specifically, the infrared receiving circuit 30 includes an infrared receiving chip U1, the output terminal of which is electrically connected to the sensing signal input terminal Out_signal. The infrared receiving chip U1 is configured to receive a reflected carrier signal of a first preset frequency, and outputs a first-level voltage signal as a sensing signal when the carrier signal of the first preset frequency is received, and outputs a second-level voltage signal as a sensing signal when the carrier signal of the first preset frequency is not received. The voltage levels of the first-level voltage signal and the second-level voltage signal are different.

[0048] For example, the first voltage level signal can be a high voltage level signal, and the second voltage level signal can be a low voltage level signal. Thus, the microprocessor 10 can determine whether a reflected carrier signal is received by using the high and low voltage level signals received at the sensing signal input terminal Out_signal, thereby determining the presence of an object within the target sensing range. Furthermore, since the infrared receiving chip U1 is limited to generating the first voltage level signal only when the received carrier signal frequency is a first preset frequency, the infrared transmitting circuit 20 needs to be designed to emit a carrier signal at the first preset frequency. When the infrared receiving chip U1 determines that it has received the carrier signal at the first preset frequency, it indicates that an object within the sensing range is present and will reflect the emitted carrier signal. This can be used in conjunction with other gesture sensing circuits to determine the user's gesture. The limitation of the infrared receiving chip U1 to receive the carrier signal at the first preset frequency prevents misjudgment caused by infrared signals in other frequency bands in the environment.

[0049] Based on the same inventive concept, this invention also provides a range hood. The range hood includes a gesture detection module, which comprises at least two sets of gesture sensing circuits with adjustable sensing distances as described in any of the above embodiments. The gesture detection module is used to perform gesture detection operations to determine the user's gesture actions.

[0050] The gesture detection module can be installed on the control panel of the range hood. When a user makes a gesture in the air in front of the control panel, the gesture detection module can recognize the gesture and determine the specific gesture, such as a left swipe, a right swipe, or a back-and-forth swipe. Based on the determined gesture, the module triggers the corresponding control command to control the operating status of the range hood. Specifically, the gesture detection module requires at least two sets of gesture sensing circuits in different locations. The movement path of the user's gesture is determined based on the response sequence and frequency of each gesture sensing circuit. Specifically, the gesture detection module can have one gesture sensing circuit at each of the three positions on the left, center, and right of the range hood's control panel. When the user waves their hand from left to right, the corresponding gesture sensing circuits at these three positions can sequentially determine that an object has passed through their respective sensing areas, triggering a response in sequence. This indicates that the user's gesture is a rightward wave, which can be associated with operations such as turning the range hood on, off, increasing / decreasing speed, etc., thus controlling the range hood.

[0051] It should be added that, in this embodiment of the invention, the various groups of gesture sensing circuits in the gesture detection module can share a microprocessor. That is, the infrared emitting circuit and the infrared receiving circuit in each group of gesture sensing circuits can be electrically connected to the same microprocessor. This saves on the number of microprocessors and reduces costs. Simultaneously, the microprocessor centrally analyzes the sensing signals of each infrared receiving circuit to determine the triggering sequence and identify the gesture action. This is not limited to determining the presence of an object within the sensing range of each infrared receiving circuit, but also enables the recognition of gesture actions. Furthermore, since the sensing distance of the gesture sensing circuits in this gesture detection module can be adjusted according to user needs or preset strategies during the use of the range hood, the distance of the gesture sensing can be adjusted to accurately capture the user's gesture actions, while reducing the risk of false triggering and improving the user experience.

[0052] Based on the same inventive concept, embodiments of the present invention also provide a control method for a range hood. Figure 5 This is a flowchart of a control method for a range hood provided in an embodiment of the present invention, see reference. Figure 5 This control method can be specifically applied to the range hood described in the above embodiment. The control method includes: S110. Using the gesture detection module, perform gesture detection operations cyclically at a preset sensing distance until the cooking process ends.

[0053] This step indicates that during operation, the range hood utilizes a gesture detection module to continuously perform gesture detection. This detection process is cyclical, with each cycle performing detection at a predetermined preset sensing distance. The gesture detection operation can be understood as the gesture sensing circuit within the module detecting the presence of objects within its sensing range and determining the order in which each circuit detects an object, thereby determining whether the user has performed a specific gesture.

[0054] S120. When a gesture is detected, execute the preset range hood operation corresponding to the gesture.

[0055] This step refers to a specific situation that may occur when the gesture detection module performs gesture detection at a preset sensing distance in any given cycle, and the corresponding control strategy. This situation occurs when the user's gesture is detected, indicating that the user intends to control the range hood and has issued a corresponding gesture control command. At this point, the range hood operation pre-bound to that gesture can be executed. Specific range hood operations could include turning the range hood on, off, increasing or decreasing its speed, etc.

[0056] The range hood control method provided in the above embodiments utilizes a gesture detection module to cyclically perform gesture detection operations within a preset sensing distance until the cooking process ends. When a gesture is detected, the preset range hood operation corresponding to the gesture is executed, thereby enabling users to control the range hood with gestures. This satisfies users' need for contactless operation during cooking, avoiding mutual contamination between users' hands and the range hood control panel, and eliminating the disadvantage of users having to approach the range hood to operate it, thus improving the user experience of the range hood.

[0057] Based on the above embodiments, modified embodiments of the above embodiments are proposed. It should be noted that, in order to keep the description brief, only the differences from the above embodiments are described in the modified embodiments.

[0058] In one embodiment, the following additional steps may be added to the above embodiments: S100: Real-time acquisition of preset sensing distance.

[0059] First, it should be noted that this step is not limited to before or after steps S110 and S120; it means that the preset sensing distance actively set by the user can be obtained at any time according to their needs. Based on this, in the next cycle, the detection should be performed according to the preset sensing distance set by the user, thereby meeting the user's needs for gesture sensing distance in actual cooking scenarios.

[0060] Figure 6 This is a flowchart of another control method for a range hood provided in an embodiment of the present invention, see reference. Figure 6 This embodiment is a supplement to the previous embodiment, in which the following additional steps are added: When no gesture is detected, the preset sensing distance is adjusted based on the detection results.

[0061] For details not covered in this embodiment, please refer to the previous embodiment.

[0062] like Figure 6 As shown, the control method provided in this embodiment of the invention includes the following steps: S210. Using the gesture detection module, perform gesture detection operations cyclically at a preset sensing distance until the cooking process ends.

[0063] S220. When a gesture is detected, execute the preset range hood operation corresponding to the gesture.

[0064] S230. When no gesture is detected, adjust the preset sensing distance according to the detection situation.

[0065] Steps S220 and S230 above indicate that when the gesture detection module performs a cyclic gesture detection operation, it may detect a gesture but not necessarily a gesture. The reasons for not detecting a gesture could be that the user did not actually perform a gesture, or that the sensing distance of the gesture detection module is incorrect, failing to accurately sense gestures at the user's current distance, thus failing to effectively detect the user's gestures. Based on these reasons, this embodiment of the invention adds steps S220 and S230 to adaptively adjust the preset sensing distance in subsequent cycles based on the actual detection situation when no gesture is detected. This ensures that the gesture sensing distance matches the user's current distance, avoiding gesture detection failure due to inaccurate sensing distance.

[0066] Based on the above embodiments, modified embodiments of the above embodiments are proposed. It should be noted that, in order to keep the description brief, only the differences from the above embodiments are described in the modified embodiments.

[0067] In one embodiment, step S230, adjusting the preset sensing distance based on the detection status when no gesture is detected, can be further refined as follows: S231. When an object is detected within a first preset time period, the preset sensing distance is reduced according to a preset adjustment range.

[0068] If an object is detected continuously for the first preset time period, it means that the gesture sensing module can continuously detect the presence of an object within its sensing range for an extended period. This object could be the user's body, a wall, or other kitchen equipment and furniture. In this case, it indicates that the sensing distance of the gesture sensing module is relatively far, and the detected object is not the user's arm, resulting in the inability to detect the user's gesture. At this point, the preset sensing distance can be gradually reduced according to a preset adjustment range. In other words, the preset sensing distance can be decreased in the next cycle. If the gesture is still not detected, the preset sensing distance can be decreased again in the cycle after that, and so on. It can be understood that during the process of gradually reducing the preset sensing distance, if the user does indeed perform a gesture, there will inevitably be a suitable preset sensing distance that can detect the gesture. At this point, S220 can be executed.

[0069] S232. If no object is detected within a second preset time, increase the preset sensing distance according to the preset adjustment range.

[0070] If no object is detected for a continuous second preset time period, it indicates that the gesture sensing module has not detected an object within the sensing area for an extended period. This means the sensing distance of the gesture sensing module is too small to detect the user's arm or even their body. In this case, the preset sensing distance can be gradually increased according to a preset adjustment range. In other words, the preset sensing distance can be increased in the next cycle. If no object or gesture is detected, the preset sensing distance can be increased again in the cycle after that, and so on. Similarly, it can be understood that during the gradual increase of the preset sensing distance, if the user does perform a gesture, there will inevitably be a suitable preset sensing distance that can detect the gesture, at which point S220 can be executed. If the user does not perform a gesture, the object will inevitably be detected, at which point S231 can be executed.

[0071] Optionally, the first preset time is t1, and the second preset time is t2, where t1 < t2.

[0072] The first preset time t1 is used to determine the duration for which an object is continuously detected. When an object is continuously detected, it indicates that a fixed object exists within the sensing range, meaning the preset sensing distance needs to be appropriately reduced; this duration does not need to be too long. The second preset time t2 is used to determine the duration for which no object is continuously detected. When no object is continuously detected, it may be because the sensing range is too small, or the sensing range is appropriate but the user has not performed a gesture. Therefore, the duration of this determination can be appropriately increased to give the user sufficient time to perform a gesture and for the gesture to be detected, avoiding the problem of failing to detect gestures due to excessively rapid adjustment of the sensing distance. For example, the first preset time t1 can be 1 minute, and the second preset time t2 can be 2 minutes.

[0073] Optionally, the distance between the user's body and palm is L, and the preset adjustment range is d; where d = k × L, 0 < k ≤ 1.

[0074] Considering that users typically move their arms towards the range hood's gesture sensor module, extending or partially extending their arms, the distance from the user's palm to the range hood is significantly less than the distance from the user's body. To avoid false triggering due to the detection of the user's body, the maximum distance for gesture sensing should be appropriately reduced. However, this reduction cannot exceed the length of the user's partially extended arm; otherwise, the sensing distance will be too small to detect normal gestures. Based on these considerations, in this embodiment of the invention, a preset adjustment range d is set to satisfy d = k × L, where k is in the range of 0 to 1, indicating that the preset adjustment range d is not longer than the length of a person's arm L. For example, k can be 0.7.

[0075] In summary, steps S231 and S232 can be understood as utilizing the adjustable sensing distance of the gesture sensing module to continuously scan within a sensing distance range that decreases and then increases again when no user gesture is detected. During this cyclical scanning process, if the user does perform a gesture, there will inevitably be a suitable preset sensing distance to detect the gesture, thereby enabling the corresponding operation of the range hood. This achieves real-time and effective detection of user gestures, solving the problem that the fixed detection range of existing gesture sensing circuits cannot adapt to complex user environments. The sensing distance can be flexibly adjusted within a larger adjustment range to meet the actual gesture control needs of users and improve the user experience.

[0076] Figure 7 This is a flowchart of another control method for a range hood provided in an embodiment of the present invention, such as... Figure 7 As shown, the embodiments of the present invention also provide a more detailed flowchart of the specific implementation process. The actual operation steps are described below: First, while the gesture sensing module in this embodiment can detect the presence of objects within its sensing range, it cannot detect the distance between the object and the gesture sensing module, thus failing to perform effective human body recognition. To address this, the control method in this embodiment employs the gesture sensing circuit provided in the aforementioned embodiment to effectively adjust the gesture sensing distance, ensuring it is always maintained at a distance that is neither prone to false triggering nor insufficient for effectively recognizing user gestures. This control method may include the following specific steps: S701: The range hood has started working.

[0077] S702: The gesture sensing module is activated and adjusts its sensing distance.

[0078] In this step, after the gesture sensing module is activated, it will adjust the infrared LED current according to the infrared LED current adjustment scheme provided in the above embodiment to change the sensing distance. It should be noted that the sensing distance of the gesture sensing module is usually set by the user according to their own needs. If the user does not set it, the system will default to setting the sensing distance to the maximum value or the sensing distance at the end of the last cooking, which can be set to S. S703: The gesture sensing module emits infrared signals to detect hand gestures.

[0079] S704: Whether the gesture was recognized.

[0080] This step uses the gesture sensing module to confirm whether the user's gesture action has been recognized. If yes, proceed to S705; otherwise, proceed to S706. S705: Operations corresponding to gesture actions performed by the range hood.

[0081] This step executes the corresponding action response (such as power on / off, airflow adjustment, etc.) based on the detected gesture type (such as waving direction, number of wavings, etc.), and then returns to S703 to continue detecting gestures. S706: Was an object detected?

[0082] This step confirms whether the gesture sensing module has detected an object within its current sensing range. If an object is detected, proceed to S707; otherwise, proceed to S709. It's important to note that the signal indicating object detection here is different from the signal indicating gesture detection in S703. If an object is present, the gesture sensing module will detect the infrared reflection signal for an extended period. However, if the user performs a waving gesture, the gesture sensing module will detect the reflection signal first, and then it will disappear. The specific logic for this determination has been detailed previously and will not be repeated here.

[0083] S707: An object has been detected and remains for a first preset time.

[0084] In this step, after the gesture sensing module detects the presence of an object, it determines whether the signal lasts for a first preset time. If yes, it proceeds to S708; otherwise, it returns to S703 to continue gesture detection. The first preset time is a pre-set detection time, primarily used to determine the user's position. This time can be adjusted based on the user's actual cooking situation. It is typically set to a relatively long duration, such as around one minute.

[0085] If the conditions in S707 are met, it indicates that an object has been present within the sensing range for an extended period. Considering that range hoods are typically mounted high up, and other large objects are usually not placed nearby in front of the range hood, if the module detects an object's prolonged presence, there are two main possibilities. One is that the gesture sensing module detects an object located far from the range hood and at a high position, such as a wall, large furniture, or an object mounted on the wall. These objects are not useful for detecting user gestures, and due to the obstruction of the object, the system cannot recognize the user's gestures behind it. In other words, the user's actual gestures must occur in front of the object, thus requiring a larger sensing distance. In this case, to ensure the accuracy of gesture sensing and to avoid interference from object movements, the maximum sensing distance can be appropriately reduced.

[0086] In another possibility, the object the range hood is constantly detecting is the user's body. In this case, some normal user movements (such as walking within the sensing range) might be interpreted as gestures. Considering that users typically face the range hood's gesture sensor module and wave with their arm extended or half-extended, the distance from their palm to the range hood is significantly less than the distance from their body. Therefore, to avoid accidental gesture detection, the maximum distance for the gesture sensor should be appropriately reduced. However, this distance cannot exceed the length of the user's half-extended arm, otherwise it will affect the user's normal gesture movements. Therefore, the spacing setting here is crucial and requires a suitable intermediate value.

[0087] S708: The gesture sensing distance is reduced by a preset adjustment range.

[0088] If the gesture sensing module here uses, for example Figure 1 The gesture sensing circuit shown can have a preset adjustment range set to a fixed value d (e.g., 5cm). This means that for every reduction in the preset adjustment range, the gesture sensing distance decreases by d (5cm), resulting in a gesture sensing distance of S = Sd. This preset adjustment range can be set to a universally applicable value using a large amount of sampled data from actual user hand gestures. This ensures the system can effectively detect user gestures while minimizing the probability of false triggering.

[0089] If the following is adopted Figure 3 or Figure 4 In a gesture sensing circuit, the preset adjustment range of the gesture sensing can be freely adjusted. This can be achieved by having the user perform several actual gestures in advance, thereby calculating the distance L between the user's body and the palm when waving. The preset adjustment range d can be set based on L, and d is directly proportional to L. For example, d = 0.7 * L (this formula is for reference only), allowing the adjustment of the gesture sensing distance to adapt to each user's actual usage. This ensures that the system can effectively detect user gestures while minimizing the probability of accidental gesture touches.

[0090] S709: No object was detected and the second preset time has been maintained.

[0091] If the gesture sensing module does not detect the presence of an object, it determines whether this state should continue for a second preset time. This second preset time is a pre-set detection time, also intended to determine the user's position. The specific time can be adjusted based on the user's actual cooking situation. This time can also be set slightly longer than the first preset time, for example, around 2 minutes. If the gesture sensor module fails to detect an object for an extended period, it's possible that the gesture sensing distance has been set and is at an optimal position. Alternatively, the user may have moved away from the range hood to perform other cooking actions. If the gesture sensing distance remains unchanged in this case, the system will be unable to effectively recognize the user's gestures. Therefore, to ensure effective gesture sensing, the gesture sensing distance should be appropriately increased to re-detect the user's location.

[0092] If the user's body is detected again at the same time after the sensing distance is increased, the system will automatically adjust the gesture sensing distance when it re-enters the S707 and S708 processes.

[0093] S710: The gesture sensing distance has been increased by a preset adjustment range.

[0094] The preset adjustment range in this step is the same as the preset adjustment range in S708. At this time, the gesture sensing distance S = S + d.

[0095] S711: Is the cooking process complete?

[0096] If successful, proceed to S712; otherwise, return to S703 to continue detecting the user's gestures.

[0097] S712: When the range hood finishes its work, the gesture sensing module is turned off (or can remain on by default). The last gesture sensing distance S is recorded as the default value and can be used the next time the range hood system works.

[0098] It should also be noted that although the range hood system in this embodiment can automatically adjust the gesture sensing distance S, the user can also manually adjust the sensing distance S of the gesture sensing module at any time (such as by clicking the range hood control panel or controlling it via a mobile application). Considering that the preset adjustment range d in this embodiment is not large, the overall distance adjustment speed is relatively slow. Therefore, this embodiment is more suitable for small kitchens or situations where the user's movement distance in the kitchen is not very large. If the user has an open kitchen and needs to move a long distance at once, and still wants to use the gesture sensing function after moving, it is recommended that the user manually adjust the sensing distance once after moving to make the gesture sensing function more accurate.

[0099] Furthermore, considering that the gesture sensing distance is frequently adjusted, users may not be able to know the specific value of the gesture sensing distance S in real time. This embodiment can employ methods such as... Figure 2 or Figure 4 The gesture sensing circuit shown uses indicator lights to indicate the sensing distance, allowing users to easily understand the current sensing distance.

[0100] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A gesture sensing circuit with adjustable sensing distance, characterized in that, It includes a microprocessor (10), an infrared emitting circuit (20), and an infrared receiving circuit (30). The microprocessor (10) includes a sensing signal input terminal, a first control signal output terminal, and at least two power supply voltage output terminals; The infrared emitting circuit (20) includes a first current regulating unit (21), an infrared emitting unit (22), and a switching unit (23); the first current regulating unit (21) includes at least two current regulating branches (210), each with a different resistance; one end of each of the at least two current regulating branches (210) is electrically connected to the at least two power supply voltage output terminals, and the other end is electrically connected to the first node; the infrared emitting unit (22) and the switching unit (23) are connected in series between the first node and the fixed potential node; the first control signal output terminal is electrically connected to the control terminal of the switching unit (23); The microprocessor (10) is configured to output a first pulse width modulation signal with a first preset frequency through the first control signal output terminal to control the switching unit (23) to turn on and off according to the first preset frequency, and the infrared emitting unit (22) to emit light and turn off according to the first preset frequency, and to emit a carrier signal with the first preset frequency. The microprocessor (10) is also configured to provide a power supply voltage to at least one of the power supply voltage output terminals; the microprocessor (10) has multiple sensing distance modes, and in different sensing distance modes, the power supply voltage output terminals provided by the microprocessor (10) are different, and the current passing through the infrared emitting unit (22) is different, so that the carrier signal has different transmission intensities. The infrared receiving circuit (30) is configured to detect the carrier signal of the first preset frequency, generate an induction signal, and provide it to the microprocessor (10) through the induction signal input terminal. The microprocessor (10) is also configured to determine, based on the sensing signal, whether there is an object within the detection range corresponding to the current sensing distance mode.

2. The gesture sensing circuit according to claim 1, characterized in that, The current regulating branch (210) includes a resistor, and the resistance value of the resistor in different current regulating branches (210) is different.

3. The gesture sensing circuit according to claim 2, characterized in that, The current regulating branch (210) also includes an indicator light. The indicator light and the resistor in the same current regulating branch (210) are connected in series. The indicator lights in different current regulating branches (210) have different light colors.

4. The gesture sensing circuit according to claim 1, characterized in that, The switching unit (23) includes a transistor; the base of the transistor is electrically connected to the first control signal output terminal, the collector of the transistor is electrically connected to the infrared emitting unit (22), and the emitter of the transistor is electrically connected to the fixed potential node.

5. The gesture sensing circuit according to claim 1, characterized in that, The microprocessor (10) also includes a second control signal output terminal; The infrared emitting circuit (20) further includes a second current adjustment unit (24), which is connected between the fixed potential node and the ground terminal; The microprocessor (10) is also configured to output a second pulse width modulation signal to the second current adjustment unit (24) through the second control signal output terminal to change the potential of the fixed potential node and adjust the current passing through the infrared emitting unit (22) so that the carrier signal has different emission intensities.

6. The gesture sensing circuit according to claim 5, characterized in that, The second current regulation unit (24) includes a voltage divider resistor and a voltage regulator capacitor, which are connected in parallel between the fixed potential node and the ground terminal; the second control signal output terminal is electrically connected to the fixed potential node.

7. The gesture sensing circuit according to claim 1, characterized in that, The infrared receiving circuit (30) includes an infrared receiving chip, and the output terminal of the infrared receiving chip is electrically connected to the sensing signal input terminal. The infrared receiving chip is configured to receive a reflected carrier signal of the first preset frequency, and output the sensing signal as a first level voltage signal when the carrier signal of the first preset frequency is received, and output the sensing signal as a second level voltage signal when the carrier signal of the first preset frequency is not received, wherein the level voltage of the first level voltage signal and the second level voltage signal are different.

8. A range hood, characterized in that, The device includes a gesture detection module, which comprises at least two sets of gesture sensing circuits with adjustable sensing distance as described in any one of claims 1-7; the gesture detection module is used to perform gesture detection operations to determine the user's gesture actions.

9. A control method for a range hood, characterized in that, Applied to the range hood as described in claim 8, the control method includes: Using the gesture detection module, gesture detection operations are performed cyclically at a preset sensing distance until the cooking process ends; When a gesture is detected, the preset operation of the range hood corresponding to the gesture is executed.

10. The control method according to claim 9, characterized in that, Also includes: The preset sensing distance is acquired in real time.

11. The control method according to claim 9, characterized in that, Also includes: When no gesture is detected, the preset sensing distance is adjusted based on the detection results.

12. The control method according to claim 11, characterized in that, When no gesture is detected, the preset sensing distance is adjusted based on the detection results, including: When an object is detected for a first preset time period, the preset sensing distance is reduced according to a preset adjustment range. If no object is detected for a second preset time, the preset sensing distance is increased by a preset adjustment range.

13. The control method according to claim 12, characterized in that, The first preset time is t1, and the second preset time is t2, where t1 < t2.

14. The control method according to claim 12, characterized in that, The distance between the user's body and palm is L, and the preset adjustment range is d; where d = k × L, 0 < k ≤ 1.

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