阅读说明：本技术 洗衣机门锁状态检测方法及装置 (Washing machine door lock state detection method and device ) 是由 杨凯 车杰 罗伦 于 2021-08-17 设计创作，主要内容包括：本说明书实施例提供一种洗衣机门锁状态检测方法及装置,方法包括：按照预设采样周期在门锁检测电路的输出端进行信号采样,若采样信号为高电平信号,则对高电平的连续采样次数进行计数,得到高电平连续计数值；在高电平连续时长大于第一预设时长时确定所述门锁装置为打开状态,并对低电平连续计数值清零。本发明可以有效剔除干扰因素,大大提高门锁状态判断的准确性。而且通过本发明在一个信号周期内就可以做出判断,实时性非常高,相对于现有技术可以快速准确的对门锁状态做出判断,能够提高门锁状态检测的有效性。(The embodiment of the specification provides a washing machine door lock state detection method and a washing machine door lock state detection device, and the method comprises the following steps: sampling a signal at the output end of the door lock detection circuit according to a preset sampling period, and counting the continuous sampling times of a high level if the sampling signal is a high level signal to obtain a high level continuous counting value; and when the high-level continuous duration is longer than a first preset duration, determining that the door lock device is in an open state, and clearing the low-level continuous count value. The invention can effectively eliminate interference factors and greatly improve the accuracy of door lock state judgment. The invention can judge in a signal period, has high real-time performance, can quickly and accurately judge the state of the door lock compared with the prior art, and can improve the effectiveness of detecting the state of the door lock.)

1. A washing machine door lock state detection method is characterized by comprising the following steps:

sampling a signal at the output end of the door lock detection circuit according to a preset sampling period, and counting the continuous sampling times of a high level if the sampling signal is a high level signal to obtain a high level continuous counting value; the input end of the door lock detection circuit is connected with a door lock device, the door lock detection circuit is used for outputting a square wave signal consisting of high level and low level alternately when the door lock device is in a closed state, and only outputting a high level signal when the door lock device is in an open state; the preset sampling period is less than one N of the duty cycle time of a signal period corresponding to the square wave signal, and N is a positive integer greater than 10;

determining that the door lock device is in an open state when the high-level continuous duration is longer than a first preset duration, and resetting the low-level continuous count value; the high-level continuous duration is the product of the high-level continuous counting value and the preset sampling period, the first preset duration is M times of the signal period, and M is a positive integer in [2,5 ].

2. The method of claim 1, further comprising:

and if the sampling signal is a high-level signal and the sampling signal is converted into a low-level signal when the high-level continuous time length is less than or equal to the first preset time length, counting the continuous sampling times of the low level from zero and clearing the high-level continuous counting value.

3. The method of claim 1, further comprising:

if the sampling signal is a low-level signal, counting the continuous sampling times of the low level to obtain a low-level continuous counting value;

and when the low-level continuous duration is longer than a first preset duration, determining that the door lock device is in a closed state, and clearing the high-level continuous count value.

4. The method of claim 3, further comprising:

and if the sampling signal is a low-level signal and the sampling signal is converted into a high-level signal when the low-level continuous time length is less than or equal to the first preset time length, counting the continuous sampling times of the high level from zero and clearing the low-level continuous counting value.

5. The method of claim 1, wherein the door lock detection circuit comprises a first diode, a second diode, a first capacitor, a second capacitor, a first transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, and a fifth resistor, wherein the second diode is a zener diode, and wherein the first transistor is an NPN-type first transistor, and wherein:

the positive electrode of the first diode is connected with the input end of the door lock detection circuit, the negative electrode of the first diode is connected with one end of the first resistor, the other end of the first resistor is respectively connected with one end of the second resistor, the negative electrode of the second diode and one end of the third resistor, the other end of the second resistor is grounded, the positive electrode of the second diode is grounded, the other end of the third resistor is respectively connected with one end of the first capacitor and the base electrode of the first triode, the other end of the first capacitor is grounded, the emitter electrode of the first triode is grounded, the collector electrode of the first triode is respectively connected with one end of the fourth resistor and one end of the fifth resistor, the other end of the fourth resistor is connected with a first preset voltage source, and the other end of the fifth resistor is connected with the output end of the door lock detection circuit, one end of the second capacitor is connected with the output end of the door lock detection circuit, and the other end of the second capacitor is grounded.

6. The method of claim 3, further comprising:

the method comprises the steps of controlling a first display lamp in a door lock state display circuit to be turned on when the door lock device is determined to be in an open state, controlling a second display lamp in the door lock state display circuit to be turned on when the door lock device is determined to be in a closed state, wherein the first display lamp and the second display lamp are different in color.

7. The method of claim 6, wherein the door lock status display circuit further comprises, in addition to the first display light and the second display light: the second triode is an NPN triode, and the third triode is a PNP triode, wherein:

one end of the sixth resistor is connected with the input end of the door lock state display circuit, the other end of the sixth resistor is connected with the base electrode of the second triode, the emitting electrode of the second triode is grounded, the collecting electrode of the second triode is connected with one end of the seventh resistor, the other end of the seventh resistor is respectively connected with the base electrode of the third triode and one end of the eighth resistor, a second preset voltage source is respectively connected with the other end of the eighth resistor and the emitting electrode of the third triode, the collecting electrode of the third triode is respectively connected with one end of the ninth resistor and one end of the tenth resistor, the other end of the ninth resistor is grounded, and the other end of the tenth resistor is connected with the first display lamp; one end of the sixth resistor is also connected with one end of the phase inverter, and the other end of the phase inverter is connected with the second display lamp;

the door lock state display circuit is used for controlling the first display lamp to be lightened and keeping the second display lamp in a turned-off state when the input end is at a high level, and controlling the second display lamp to be lightened and keeping the first display lamp in a turned-off state when the input end is at a low level.

8. The method of claim 7, further comprising a third capacitor, wherein one end of the third capacitor is connected to ground, and the other end of the third capacitor is connected to the collector of the third transistor.

9. A washing machine door lock state detection device is characterized by comprising:

the sampling module is used for sampling signals at the output end of the door lock detection circuit according to a preset sampling period, and counting the continuous sampling times of a high level to obtain a continuous high level count value if the sampling signals are high level signals; the input end of the door lock detection circuit is connected with a door lock device, the door lock detection circuit is used for outputting a square wave signal consisting of high level and low level alternately when the door lock device is in a closed state, and only outputting a high level signal when the door lock device is in an open state; the preset sampling period is less than one N of the duty cycle time of a signal period corresponding to the square wave signal, and N is a positive integer greater than 10;

the judging module is used for determining that the door lock device is in an open state when the high-level continuous duration is longer than a first preset duration, and resetting the low-level continuous count value; the high-level continuous time length is the product of the high-level continuous counting value and the preset sampling period, the first preset time length is M times of the signal period, and M is a positive integer in [1,5 ].

10. The apparatus of claim 9,

the sampling module is further configured to: if the sampling signal is a low-level signal, counting the continuous sampling times of the low level to obtain a low-level continuous counting value;

the judging module is further configured to: and when the low-level continuous duration is longer than a first preset duration, determining that the door lock device is in a closed state, and clearing the high-level continuous count value.

Technical Field

One or more embodiments of the present disclosure relate to the field of air conditioning technologies, and in particular, to a method and an apparatus for detecting a door lock state of a washing machine.

Background

In a drum washing machine, many control logics are involved in the rapid detection and normal judgment of the door lock state. For example, some washing machines may force the washing machine to stop working when the door lock state is an open state, and when the door lock state is a closed state, the door lock is controlled to be changed to the open state by a button, so that it is very important to detect the normal opening and closing of the door lock.

In the prior art, the duty ratio of square wave signals is calculated when a door lock is closed, a plurality of signals need to be read in preset time, the calculated duty ratio is inaccurate due to the fact that the number of the read signals is too small, the operation time is increased due to the fact that the number of the read signals is too large, the existing signals are converted into square wave signals with the duty ratio of about 80% according to input 220V and 50HZ alternating voltages, and each detection time exceeds 100 ms.

Disclosure of Invention

One or more embodiments of the present specification describe a washing machine door lock state detection method and apparatus.

According to a first aspect, there is provided a washing machine door lock state detection method, comprising:

sampling a signal at the output end of the door lock detection circuit according to a preset sampling period, and counting the continuous sampling times of a high level if the sampling signal is a high level signal to obtain a high level continuous counting value; the input end of the door lock detection circuit is connected with a door lock device, the door lock detection circuit is used for outputting a square wave signal consisting of high level and low level alternately when the door lock device is in a closed state, and only outputting a high level signal when the door lock device is in an open state; the preset sampling period is less than one N of the duty cycle time of a signal period corresponding to the square wave signal, and N is a positive integer greater than 10;

determining that the door lock device is in an open state when the high-level continuous duration is longer than a first preset duration, and resetting the low-level continuous count value; the high-level continuous time length is the product of the high-level continuous counting value and the preset sampling period, the first preset time length is M times of the signal period, and M is a positive integer in [2,5 ].

According to a second aspect, there is provided a washing machine door lock state detection apparatus, comprising:

the sampling module is used for sampling signals at the output end of the door lock detection circuit according to a preset sampling period, and counting the continuous sampling times of a high level to obtain a continuous high level count value if the sampling signals are high level signals; the input end of the door lock detection circuit is connected with a door lock device, the door lock detection circuit is used for outputting a square wave signal consisting of high level and low level alternately when the door lock device is in a closed state, and only outputting a high level signal when the door lock device is in an open state; the preset sampling period is less than one N of the duty cycle time of a signal period corresponding to the square wave signal, and N is a positive integer greater than 10;

the judging module is used for determining that the door lock device is in an open state when the high-level continuous duration is longer than a first preset duration, and resetting the low-level continuous count value; the high-level continuous time length is the product of the high-level continuous counting value and the preset sampling period, the first preset time length is M times of the signal period, and M is a positive integer in [1,5 ].

According to the method and the device for detecting the door lock state of the washing machine, signal sampling is carried out at the output end of a door lock detection circuit according to a preset sampling period, and if a sampling signal is a high-level signal, the continuous sampling times of a high level are counted to obtain a continuous high-level count value; and when the high-level continuous duration is longer than a first preset duration, determining that the door lock device is in an open state, and clearing the low-level continuous count value. And the high-level continuous duration is the product of the high-level continuous counting value and the preset sampling period, the first preset duration is a signal period which is M times, when the high-level continuous duration is longer than the first preset duration, the proportion occupied by the high level is very large and far exceeds the duration of one signal period, so that the door lock device is in an open state certainly at the moment, and the door lock detection circuit can always output the high level when the door lock device is in the open state. Therefore, interference factors can be effectively eliminated by comparing the high-level continuous time with the first preset time, and the accuracy of door lock state judgment is greatly improved. The invention can judge in a signal period, has high real-time performance, can quickly and accurately judge the state of the door lock compared with the prior art, and can improve the effectiveness of detecting the state of the door lock.

Drawings

In order to more clearly illustrate the embodiments of the present specification or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present specification, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic flow chart of a method for detecting the state of a door lock of a washing machine according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of a door lock detection circuit according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a door lock state display circuit in one embodiment of the present disclosure.

Description of the drawings:

l1 — input of door lock detection circuit; test-the output end of the door lock detection circuit; d1 — first diode; d2 — second diode; c1 — first capacitance; c2 — second capacitance; q1-first triode; r1 — first resistance; r2 — second resistance; r3 — third resistance; r4-fourth resistor; r5-fifth resistor;

q2-second transistor; q3-third transistor; d3 — third diode; c3 — third capacitance; e1-first display light; e2-second display light; r6-sixth resistance; r7 — seventh resistor; r8 — eighth resistance; r9 — ninth resistor; r10 — tenth resistance.

Detailed Description

The scheme provided by the specification is described below with reference to the accompanying drawings.

In a first aspect, the present invention provides a washing machine door lock state detection method, which may be performed by a control unit that may execute computer code to implement the steps of the method provided by the present invention. As shown in fig. 1, the method may include the following steps S110 to S120:

s110, sampling a signal at the output end of the door lock detection circuit according to a preset sampling period, and counting the continuous sampling times of a high level if the sampling signal is a high level signal to obtain a high level continuous counting value;

the input end of the door lock detection circuit is connected with a door lock device, the door lock detection circuit is used for outputting a square wave signal consisting of high level and low level alternately when the door lock device is in a closed state, and only outputting a high level signal when the door lock device is in an open state; the preset sampling period is less than one N of the duty cycle time of the signal period corresponding to the square wave signal, and N is a positive integer greater than 10.

It can be understood that when the door lock device is in an open state, the door lock detection circuit only outputs a high level signal; when the door lock device is closed, the door lock detection circuit can alternately output a low level and a high level, namely, a square wave signal is output.

It can be understood that sampling is performed at the output terminal of the door lock detection circuit every preset sampling period. The preset sampling period (for example, 1ms) is less than N times of the duty cycle time of the signal period corresponding to the square wave signal, and N is greater than 10, so that the preset sampling period is much less than the duty cycle time of the signal period corresponding to the square wave signal, and the duty cycle time refers to the time length occupied by a high level in one signal period, so that multiple times of sampling can be performed in one signal period of the square wave signal to obtain multiple sampling signals.

It can be understood that if the sampling signal is a continuous high-level signal, the continuous sampling times of the high-level signal are counted to obtain a corresponding high-level continuous count value.

S120, when the high-level continuous duration is longer than a first preset duration, determining that the door lock device is in an open state, and resetting a low-level continuous count value;

the high-level continuous duration is the product of the high-level continuous counting value and the preset sampling period, the first preset duration is M times of the signal period, and M is a positive integer in [2,5 ].

That is, the present invention determines whether the door lock device is in the open state based on the high level consecutive count value.

It can be understood that the duration of the high-level continuous period is p1 times of the preset sampling period, and p1 is a high-level continuous count value. The first preset duration is M times of the signal period. Along with the increase of the sampling times, when the product of the continuous high-level sampling times and the preset sampling period is larger than the signal period of M times, the proportion occupied by the high level is very large and is far longer than the duration of one signal period, so that the door lock device is in an open state certainly, and the door lock detection circuit can always output the high level when the door lock device is in the open state.

It can be understood that the low level continuous count is cleared when it is determined that the door lock device is in the open state, in order to subsequently determine whether the door lock device will enter the closed state. The high level continuous count value cannot be cleared at this time because there is a possibility that the sampling signal is still a high level signal at the next sampling and the high level continuous count value cannot be cleared until the sampling signal changes to a low level signal.

In practice, there is also a case: when sampling, the sampling signal is converted from a high level signal into a low level signal, and the product of the continuous sampling times of the high level signal and the preset sampling period is less than or equal to M times of the signal period, so that the door lock device is not necessarily in a closed state and is not necessarily in an open state, and therefore judgment is not made. However, since the low level signal is acquired, the number of times of continuous sampling of the low level is counted from zero, and whether the door lock device is in the closed state is determined according to the number of times of continuous sampling of the low level. Meanwhile, preparation is made for judging whether the door lock device is in an open state next time, and the high-level continuous count value is cleared.

That is, the method provided by the present invention may further include: and if the sampling signal is a high-level signal and the sampling signal is converted into a low-level signal when the high-level continuous time length is less than or equal to the first preset time length, counting the continuous sampling times of the low level from zero and clearing the high-level continuous counting value.

It is understood that the initial value is zero regardless of whether the high level continuous count value or the low level continuous count value.

In a specific implementation, step S110 may further include: if the sampling signal is a low-level signal, counting the continuous sampling times of the low level to obtain a low-level continuous counting value; at this time, S120 may further include: and when the low-level continuous duration is longer than a first preset duration, determining that the door lock device is in a closed state, and clearing the high-level continuous count value.

That is, whether the door lock device is in the closed state is determined by the low level continuous count value.

That is, if the sampling signal is a continuous low-level signal, the number of consecutive samples of the low-level signal is counted to obtain a corresponding low-level continuous count value. The low level continuous duration is p2 times the preset sampling period, and p2 is a low level continuous count value. The first preset duration is M times of the signal period. Along with the increase of the sampling times, when the product of the continuous low-level sampling times and the preset sampling period is larger than the signal period of M times, the proportion occupied by the low level is very large and far exceeds the duration of one signal period, so that the door lock device is in a closing state certainly, and the door lock detection circuit can output square wave signals with high levels and low levels alternated when the door lock device is in the closing state, namely the door lock detection circuit can output low-level signals only when the door lock device is in the closing state.

It can be understood that the high-level continuous count is cleared when the door lock device is determined to be in the closed state, so as to prepare for subsequently judging whether the door lock device can enter the open state. The low level continuous count value cannot be cleared at this time because there is a possibility that the sampling signal is still a low level signal at the next sampling and the high level continuous count value cannot be cleared until the sampling signal changes to a high level signal.

In practice, there is also a case: when sampling, the sampling signal is converted from low level to high level signal, and the product of the sampling times of the low level signal and the preset sampling period is less than or equal to M times of the signal period, at this time, the door lock device may still be in a closed state, and may also enter an open state, so that no judgment is made. However, since the high level signal is acquired at this time, the number of consecutive high level samples is counted from zero, and whether the door lock device is in the open state is determined based on the number of consecutive high level samples. Meanwhile, preparation is made for judging whether the next door lock state is a closed state, and the low-level continuous count value is cleared.

That is, the method provided by the present invention may further include: and if the sampling signal is a low-level signal and the sampling signal is converted into a high-level signal when the low-level continuous time length is less than or equal to the first preset time length, counting the continuous sampling times of the high level from zero, and clearing the low-level continuous count value.

In specific implementation, the door lock detection circuit can be implemented by adopting various structures, and an optional structure is provided as follows: as shown in fig. 2, the latch detecting circuit includes a first diode D1, a second diode D2, a first capacitor C1, a second capacitor C2, a first transistor Q1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a fifth resistor R5, the second diode D2 is a zener diode, the first transistor Q1 is an NPN-type first transistor Q1, wherein:

the positive electrode of the first diode D1 is connected to the input end of the door lock detection circuit, the negative electrode of the first diode D1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to one end of the second resistor R2, the negative electrode of the second diode D2 and one end of the third resistor R3, the other end of the second resistor R2 is grounded, the positive electrode of the second diode D2 is grounded, the other end of the third resistor R3 is connected to one end of the first capacitor C1 and the base of the first triode Q1, the other end of the first capacitor C1 is grounded, the emitter of the first triode Q1 is grounded, the collector of the first triode Q1 is connected to one end of the fourth resistor R4 and one end of the fifth resistor R5, the other end of the fourth resistor R4 is connected to a first preset voltage source, the other end of the fifth resistor R5 is connected with the output end of the door lock detection circuit, one end of the second capacitor C2 is connected with the output end of the door lock detection circuit, and the other end of the second capacitor C2 is grounded.

In fig. 2, the input terminal is LI terminal, and the output terminal is test terminal. The first preset voltage source is 5 v.

In practice, when the door lock device is in the open state, the input terminal L1 is at low level, so that the first transistor is in the off state, and the output terminal is pulled high by the first predetermined voltage source to output a high level signal. When the door lock device is in the closed state, the input terminal L1 is a sine wave signal, such as 220V/50hz sine wave signal. After the sine wave signal passes through the first diode, only one positive waveform and one negative waveform in one signal period remain, and the negative waveform becomes 0. For the part of the positive waveform with the voltage higher than the conducting voltage of the base electrode of the first triode, the first triode is conducted, and the voltage of the output end is pulled down by the grounding end to become low level. And the part of the positive waveform voltage lower than the conducting voltage of the base electrode of the first triode and the part of the negative waveform changed into 0 all output high level signals because the first triode is in a cut-off state. It can be seen that when the door lock device is in a closed state, the output end can output a square wave signal formed by alternately high level signals and low level signals.

From fig. 2, the resistance of the first resistor may be selected to be about 440k ohms, the resistance of the second resistor may be selected to be about 2.2k ohms, the resistance of the third resistor may be selected to be about 470 ohms, the resistance of the fourth resistor may be selected to be about 4.7k ohms, the resistance of the fifth resistor may be selected to be about 1k ohms, and the floating rate of the resistance of each resistor is not more than 5%. The first diode can be responsible for IN4007, the first triode can be selected to be 5551, the capacity of the first capacitor can be 0.001u, the capacity of the second capacitor can be 0.01u, and the like.

In the door lock detection circuit, the second diode and the first capacitor play a role in stabilizing voltage, and damage to the first triode caused by voltage surge is avoided.

In specific implementation, in order to make the state of unlocking the door lock device more intuitive for the user, the method provided by the invention may further include: the method comprises the steps of controlling a first display lamp in a door lock state display circuit to be turned on when the door lock device is determined to be in an open state, controlling a second display lamp in the door lock state display circuit to be turned on when the door lock device is determined to be in a closed state, wherein the first display lamp and the second display lamp are different in color.

That is, the execution main body (e.g., control unit) of the present invention is connected to the input terminal of the door lock state display circuit, thereby controlling the turning on and off of the first display lamp and the second display lamp in the door lock state display circuit. Specifically, when the door lock device is in an open state, the first display lamp is controlled to be turned on, when the door lock device is in a closed state, the second display lamp is controlled to be turned on, and the colors of the first display lamp and the second display lamp are different, so that the first display lamp and the second display lamp are conveniently distinguished.

In an implementation, when the control unit determines that the door lock device is in the open state, the control unit outputs the high level, and when the control unit determines that the door lock device is in the closed state, the specific structure of the door lock state display circuit may be various, as shown in fig. 3, and one of the following structures is described:

the door lock state display circuit further includes, in addition to the first indicator light E1 and the second indicator light E2: a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a second transistor Q2, a third transistor Q3, and a first inverter, wherein the second transistor Q2 is an NPN transistor, and the third transistor Q3 is a PNP transistor, and wherein:

one end of the sixth resistor R6 is connected to the input end of the door lock status display circuit, the other end of the sixth resistor R6 is connected to the base of the second triode Q2, the emitter of the second triode Q2 is grounded, the collector of the second triode Q2 is connected to one end of the seventh resistor R7, the other end of the seventh resistor R7 is connected to the base of the third triode Q3 and one end of the eighth resistor R8, the second preset voltage source is connected to the other end of the eighth resistor R8 and the emitter of the third triode Q3, the collector of the third triode Q3 is connected to one end of the ninth resistor R9 and one end of the tenth resistor R10, the other end of the ninth resistor R9 is grounded, and the other end of the tenth resistor R10 is connected to the first display lamp E1; one end of the sixth resistor R6 is further connected to one end of the inverter, and the other end of the inverter is connected to the second display lamp E2;

the door lock state display circuit is used for controlling the first display lamp E1 to be turned on and keeping the second display lamp E2 in an off state when the input end is at a high level, and controlling the second display lamp E2 to be turned on and keeping the first display lamp E1 in an off state when the input end is at a low level.

Wherein the second voltage source is 12 v.

It can be understood that when the door lock device is opened, the control unit outputs a high level, the second triode is conducted at the moment, and a branch of the second preset voltage source, the eighth resistor, the seventh resistor, the collector of the second triode, the emitter of the second triode and the grounding end is conducted, so that the base voltage of the third triode is lower than the emitter voltage of the third triode, the third triode is conducted, and thus the branch of the second preset voltage source, the emitter of the third triode, the collector of the third triode, the tenth resistor and the first display lamp is conducted, and the first display lamp is turned on. At this time, when the input end of the door lock state display circuit is at a high level, the input end of the door lock state display circuit is changed into a low level through the inverter, so that the second display lamp is in an off state.

It can be understood that when the door lock device is closed, the control unit outputs a low level, the second triode is cut off, the third triode is cut off, and the first display lamp is in an off state. But the second display lamp is lighted because the low level is transited to the high level after passing through the inverter.

Of course, referring to fig. 3, a third diode D3 may be provided in the door lock state display circuit, the third diode may be provided between the sixth resistor and the first display lamp, the positive electrode may be connected to the sixth resistor, and the negative electrode may be connected to the first display lamp.

Therefore, when the first display lamp is short-circuited, the base electrode of the third triode is pulled down by the third diode, the third triode and the second triode are cut off, and the two triodes cannot be damaged. And when the short circuit is eliminated, the circuit can restore normal operation. After the normal work is recovered, in order to ensure that the third diode is in a cut-off state, the cathode voltage of the third triode is higher than the anode voltage by selecting proper resistance values for the resistors. After the third diode enters the cut-off state, other parts of the circuit cannot be influenced.

It can be seen that when the output terminal of the door lock status display circuit is short-circuited, the two triodes are not damaged because the third diode D3 is provided. After the short circuit is eliminated, the circuit can automatically recover to be normal, thereby playing a role in protection.

In a specific implementation, as shown in fig. 3, the door lock state display circuit may further include a third capacitor C3, one end of the third capacitor is grounded, and the other end of the third capacitor is connected to the collector of the third transistor. The third capacitor is arranged to prevent instantaneous maloperation and prevent reverse breakdown of the triodes by static electricity, and the protection effect is achieved on the two triodes in the circuit.

The invention provides a washing machine door lock state detection method, which comprises the steps of sampling a signal at the output end of a door lock detection circuit according to a preset sampling period, and counting the continuous sampling times of a high level to obtain a continuous high level count value if the sampling signal is a high level signal; and when the high-level continuous duration is longer than a first preset duration, determining that the door lock device is in an open state, and clearing the low-level continuous count value. And the high-level continuous duration is the product of the high-level continuous counting value and the preset sampling period, the first preset duration is a signal period which is M times, when the high-level continuous duration is longer than the first preset duration, the proportion occupied by the high level is very large and far exceeds the duration of one signal period, so that the door lock device is in an open state certainly at the moment, and the door lock detection circuit can always output the high level when the door lock device is in the open state. Therefore, interference factors can be effectively eliminated by comparing the high-level continuous time with the first preset time, and the accuracy of door lock state judgment is greatly improved. The invention can judge in a signal period, has high real-time performance, can quickly and accurately judge the state of the door lock compared with the prior art, and can improve the effectiveness of detecting the state of the door lock.

In a second aspect, the present invention provides a door lock state detecting device for a washing machine, comprising:

the sampling module is used for sampling signals at the output end of the door lock detection circuit according to a preset sampling period, and counting the continuous sampling times of a high level to obtain a continuous high level count value if the sampling signals are high level signals; the input end of the door lock detection circuit is connected with a door lock device, the door lock detection circuit is used for outputting a square wave signal consisting of high level and low level alternately when the door lock device is in a closed state, and only outputting a high level signal when the door lock device is in an open state; the preset sampling period is less than one N of the duty cycle time of a signal period corresponding to the square wave signal, and N is a positive integer greater than 10;

the judging module is used for determining that the door lock device is in an open state when the high-level continuous duration is longer than a first preset duration, and resetting the low-level continuous count value; the high-level continuous time length is the product of the high-level continuous counting value and the preset sampling period, the first preset time length is M times of the signal period, and M is a positive integer in [1,5 ].

In particular implementation, the sampling module is further configured to: if the sampling signal is a low-level signal, counting the continuous sampling times of the low level to obtain a low-level continuous counting value; the judging module is further configured to: and when the low-level continuous duration is longer than a first preset duration, determining that the door lock device is in a closed state, and clearing the high-level continuous count value.

It is understood that, for the device provided in the embodiment of the present invention, for the explanation, examples, and beneficial effects of the related contents, reference may be made to the corresponding parts in the foregoing method, and details are not described here.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, as for the apparatus embodiment, since it is substantially similar to the method embodiment, the description is relatively simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

Those skilled in the art will recognize that, in one or more of the examples described above, the functions described in this disclosure may be implemented in hardware, software, hardware, or any combination thereof. When implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium.

The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made on the basis of the technical solutions of the present invention should be included in the scope of the present invention.