Pyroelectric human body sensor

Abstract

The embodiment of the utility model provides a pyroelectric human body sensor. The pyroelectric human body sensor comprises a pyroelectric sensor, a signal amplification filter circuit and a controller, the controller comprises an AD sampling circuit and a threshold comparison module; wherein the input end of the signal amplification filter circuit is connected with the output end of the pyroelectric sensor, and the signal amplification filter circuit is used for receiving a detection signal sent by the pyroelectric sensor and amplifying the detection signal; a first pin of the controller is connected with the output end of the signal amplification filter circuit and is used for receiving the amplified detection signal; the AD sampling circuit is used for generating a digital signal based on the amplified detection signal; and the threshold comparison module is used for comparing the digital signal with a preset threshold so as to determine that the human body moves when a comparison result meets a preset condition. The circuit is simpler in structure and lower in power consumption.

Description

Technical Field

[0001] The present disclosure relates to the field of sensor technology, and in particular to a pyroelectric human body sensor. Background Art

[0002] The pyroelectric human body sensor works based on the principle of pyroelectricity. The sensor itself does not emit any form of energy, but passively receives and detects infrared radiation energy or energy changes from the environment to complete the detection purpose. The pyroelectric human body sensor is mainly composed of three parts: Fresnel lens, pyroelectric sensor and signal processing. The Fresnel lens can focus the infrared radiation radiated by the human body onto the pyroelectric sensor, and at the same time produce alternating infrared viewing areas and blind areas to adapt to the characteristics of the pyroelectric sensor that requires the signal to change continuously; the pyroelectric sensor converts the infrared signal of the human body into an electrical signal, outputs it in the form of voltage or current, and amplifies the signal through an operational amplifier to achieve the purpose of controlling the circuit. However, the circuit structure of the existing pyroelectric human body sensor is complex, resulting in excessive power consumption of the sensor. Utility Model Content

[0003] The disclosed embodiment provides a pyroelectric human body sensor, which is used to solve the problems of complex circuit structure and high power consumption of existing pyroelectric human body sensors.

[0004] Based on the above problems, in the first aspect, a pyroelectric human body sensor is provided, characterized in that it includes: a pyroelectric sensor, a signal amplification and filtering circuit, and a controller; the controller includes: an AD sampling circuit and a threshold comparison module;

[0005] Wherein, the input end of the signal amplifying and filtering circuit is connected to the output end of the pyroelectric sensor, and is used to receive the detection signal sent by the pyroelectric sensor and amplify the detection signal;

[0006] The first pin of the controller is connected to the output end of the signal amplification and filtering circuit, and is used to receive the amplified detection signal;

[0007] The AD sampling circuit is used to generate a digital signal based on the amplified detection signal;

[0008] The threshold comparison module is used to compare the digital signal with a preset threshold to determine that human body movement occurs when the comparison result meets a preset condition.

[0009] In one embodiment of the first aspect, the AD sampling circuit includes an ADC differential sampling circuit; the threshold comparison module includes a threshold comparison circuit; the second pin of the controller is connected to the output end of the pyroelectric sensor; the ADC differential sampling circuit is used to differentiate the amplified detection signal received by the first pin from the original detection signal received by the second pin, and then convert the differentiated signal into a digital signal; the threshold comparison circuit is used to compare the converted digital signal with a first preset threshold.

[0010] In another embodiment of the first aspect, the AD sampling circuit includes: a first AD sampling circuit and a second AD sampling circuit; the threshold comparison module includes a threshold comparison circuit; the second pin of the controller is connected to the output end of the pyroelectric sensor; and the signal received by the second pin is transmitted to the second AD sampling circuit; the first AD sampling circuit is used to convert the amplified detection signal received by the first pin into a first digital signal; the threshold comparison circuit is used to compare the first digital signal with a preset threshold.

[0011] In another embodiment of the first aspect, a timer; the controller further includes a processor; the processor includes a threshold comparison module; the timer is used to trigger an interrupt to wake up the processor whenever the timing time is reached; the processor is used to compare the digital signal generated by the AD sampling circuit with a preset threshold through the threshold comparison module after being awakened, so as to determine that human body movement occurs when the comparison result meets the preset condition. The controller is used to trigger an internal interrupt to wake up the processor when the comparison result meets the preset condition, so as to determine that human body movement occurs.

[0012] In another embodiment of the first aspect, the processor further includes a difference operation module; the processor is also used to, after determining that human body movement has occurred, perform a difference operation on the digital signal generated by the AD sampling circuit and the reference detection signal through the difference operation module each time the timing time is reached and after being awakened, and perform human body micro-movement detection by analyzing and processing the obtained difference.

[0013] In another embodiment of the first aspect, a timer; the controller also includes a processor; the processor includes a difference operation module; the timer is used to start timing after determining that human body movement has occurred; and whenever the timing time is reached, an interrupt is triggered to wake up the processor; the processor is used to perform a difference operation on the digital signal collected by the AD sampling circuit and the reference detection signal through the difference operation module; and perform human body micro-movement detection by analyzing and processing the obtained difference.

[0014] In another embodiment of the first aspect, a timer; the controller also includes a processor; the processor includes a difference operation module; the timer is used to start timing after determining that human body movement has occurred; and whenever the timing time is reached, an interrupt is triggered to wake up the processor; the second AD sampling circuit is used to convert the original detection signal received by the second pin into a second digital signal; the processor is used to perform a difference operation on the first digital signal and the second digital signal through the difference operation module; and human body micro-movement detection is performed by analyzing and processing the obtained difference.

[0015] In another embodiment of the first aspect, the signal amplification and filtering circuit includes a single-stage amplifier circuit; the single-stage amplifier circuit includes: an operational amplifier OPA, a first feedback resistor R1, a first filter capacitor C1, a second feedback resistor R2, and a second filter capacitor C2; wherein the non-inverting input terminal of the operational amplifier OPA is connected to the detection signal output S pole of the pyroelectric sensor; the inverting input terminal of the operational amplifier OPA is respectively connected to one end of the first feedback resistor R1, one end of the second feedback resistor R2, and one end of the second filter capacitor C2; the other end of the first feedback resistor R1 is connected to one end of the first filter capacitor C1; the other end of the first filter capacitor C1 is grounded; the output terminal of the operational amplifier OPA is respectively connected to the first pin of the controller, the other end of the second feedback resistor R2, and the other end of the second filter capacitor C2.

[0016] In another embodiment of the first aspect, the signal amplification and filtering circuit includes a single-stage amplifier circuit; the single-stage amplifier circuit includes: an operational amplifier OPA, a first feedback resistor R1, a first filter capacitor C1, a second feedback resistor R2, and a second filter capacitor C2; wherein the non-inverting input terminal of the operational amplifier OPA is connected to the detection signal output S pole of the pyroelectric sensor; the inverting input terminal of the operational amplifier OPA is respectively connected to one end of the first feedback resistor R1, one end of the second feedback resistor R2, and one end of the second filter capacitor C2; the other end of the first feedback resistor R1 is connected to one end of the first filter capacitor C1; the other end of the first filter capacitor C1 is grounded; the output terminal of the operational amplifier OPA is respectively connected to the first pin of the controller, the other end of the second feedback resistor R2, and the other end of the second filter capacitor C2; the detection signal output S pole of the pyroelectric sensor is connected to the second pin of the controller.

[0017] In another embodiment of the first aspect, the controller is further configured to control the processor to continue to remain in a dormant state when the comparison result does not meet a preset condition.

[0018] In yet another implementation of the first aspect, the processor is further configured to enter a dormant state after performing human motion detection; human motion detection includes: human movement and / or human micro-movement.

[0019] The beneficial effects of the embodiments of the present disclosure include:

[0020] A pyroelectric human body sensor provided by an embodiment of the present disclosure includes: a pyroelectric sensor, a signal amplifying and filtering circuit, and a controller; the controller includes: an AD sampling circuit and a threshold comparison module; wherein the input end of the signal amplifying and filtering circuit is connected to the output end of the pyroelectric sensor, for receiving a detection signal sent by the pyroelectric sensor and amplifying the detection signal; the first pin of the controller is connected to the output end of the signal amplifying and filtering circuit, for receiving the amplified detection signal; the AD sampling circuit is used to generate a digital signal based on the amplified detection signal; the threshold comparison module is used to compare the digital signal with a preset threshold, so as to determine that human body movement occurs when the comparison result meets the preset condition. The pyroelectric human body sensor provided by the present disclosure processes the detection signal through the AD sampling circuit and the threshold comparison module integrated in the controller, which simplifies the external circuit design and reduces the power consumption of the sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 One of the schematic diagrams of the structure of the pyroelectric human body sensor provided in the embodiment of the present disclosure;

[0022] Figure 2 A schematic diagram of the structure of a pyroelectric human body sensor provided for related technologies;

[0023] Figure 3 The second schematic diagram of the structure of the pyroelectric human body sensor provided in the embodiment of the present disclosure;

[0024] Figure 4 The third schematic diagram of the structure of the pyroelectric human body sensor provided in the embodiment of the present disclosure;

[0025] Figure 5 The fourth structural schematic diagram of the pyroelectric human body sensor provided in the embodiment of the present disclosure;

[0026] Figure 6 The fifth structural diagram of the pyroelectric human body sensor provided in the embodiment of the present disclosure;

[0027] Figure 7 One of the schematic diagrams of the circuit structure of the pyroelectric human body sensor provided in the embodiment of the present disclosure;

[0028] Figure 8 This is a second schematic diagram of the circuit structure of the pyroelectric human body sensor provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] The embodiment of the present disclosure provides a pyroelectric human body sensor. The preferred embodiment of the present disclosure is described below in conjunction with the drawings of the specification. It should be understood that the preferred embodiment described here is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure. In addition, the embodiments and features in the embodiments of the present application can be combined with each other if there is no conflict.

[0030] The present disclosure provides a pyroelectric human body sensor such as Figure 1 As shown, it includes: a pyroelectric sensor 101, a signal amplification and filtering circuit 102, and a controller 103; the controller 103 includes: an analog-to-digital conversion (AD, Analogue to Digital) sampling circuit 1031 and a threshold comparison module 1032;

[0031] The input end of the signal amplifying and filtering circuit 102 is connected to the output end of the pyroelectric sensor 101, and is used to receive the detection signal sent by the pyroelectric sensor 101 and amplify the detection signal;

[0032] The first pin of the controller 103 is connected to the output end of the signal amplifying and filtering circuit 102, and is used to receive the amplified detection signal;

[0033] AD sampling circuit 1031, used to generate a digital signal based on the amplified detection signal;

[0034] The threshold comparison module 1032 is used to compare the digital signal with a preset threshold to determine that human body movement occurs when the comparison result meets a preset condition.

[0035] Figure 2 The schematic diagram of the pyroelectric sensor processing circuit provided for the related technology, in which the pyroelectric human body sensor can detect the infrared rays emitted by humans or certain animals and convert them into electrical signals for output. Figure 2 As shown, the pyroelectric human body sensor is usually provided with a pyroelectric sensor (also called a passive infrared detection sensor (PIR, Passive Infrared Sensor)) 201, an analog signal amplification and filtering circuit 202, a threshold comparison circuit 203, and a controller 204 and other main parts.

[0036] Among them, the pyroelectric sensor 201 is a sensor that can detect infrared rays emitted by humans or animals and output electrical signals. The analog signal amplification and filtering circuit 202 includes a first-stage amplification and filtering circuit and a second-stage amplification and filtering circuit, which amplifies the microvolt to millivolt signal output by the pyroelectric sensor 201 to the 1 volt level; the analog signal processed by the analog signal amplification and filtering circuit 202 is then input into the threshold comparison circuit 203, which is composed of two comparators to judge and compare the signal amplitude. If there is human movement, the threshold comparison circuit 203 can output the corresponding level to the controller 204, so that the controller 204 can perform subsequent control operations. For example: when the threshold comparison circuit 203 outputs a high level, an interrupt is generated to wake up the controller 204, so that the controller 204 sends a signal that someone is moving.

[0037] However, if Figure 2 In the pyroelectric sensor processing circuit shown, an analog signal amplification and filtering circuit 202 and a threshold comparison circuit 203 are designed outside the controller 204, and four operational amplifiers are used in the circuit, which not only increases the complexity of the circuit design, but also the multi-stage amplification increases the noise, consumes more current, and increases the power consumption.

[0038] In the disclosed embodiment, the AD sampling circuit 1031 and the threshold comparison module 1032 can be integrated into the controller 103. This makes the external circuit design simple and the power consumption lower. The controller 103 can be implemented as a chip with a system on a chip (SOC, System on a Chip) (for example: a micro-control unit (MCU, Micro-controller unit)), which can integrate multiple functional components including a central processing unit (CPU, Central Processing Unit) (hereinafter referred to as the processor). The chip can be an existing one or designed by itself, which will not be repeated here.

[0039] Furthermore, in the disclosed embodiment, since the signal output by the pyroelectric sensor is at the microvolt and millivolt level, generally only 2 to 3 mV at most, the signal can be amplified to the 1V level by the signal amplification and filtering circuit 102. The AD sampling circuit 1031 in the controller 103 is used to generate a digital signal based on the amplified detection signal for subsequent analysis and detection of human body micro-movements. Therefore, comparing the amplified signal with the corresponding preset threshold can first determine that the human body has moved. Therefore, a digital signal can be generated based on the original detection signal through the signal amplification and filtering circuit 102 and the AD sampling circuit 1031, and the digital signal can be compared with the corresponding preset threshold through the threshold comparison module 1032, and finally a judgment is made whether there is a person based on the comparison result.

[0040] Furthermore, the threshold comparison module 1032 can be implemented as a threshold comparison circuit, that is, the AD sampling circuit 1031 and the threshold comparison circuit 1032 are integrated in the controller 103. In this way, the threshold comparison step can be executed by a hardware circuit without the need for the processor to calculate through software. The processor can be in a sleep state, saving power consumption.

[0041] In another embodiment provided by the present disclosure, Figure 3 As shown, the AD sampling circuit 1031 includes an ADC differential sampling circuit; the threshold comparison module includes a threshold comparison circuit;

[0042] The second pin of the controller is connected to the output end of the pyroelectric sensor;

[0043] An ADC differential sampling circuit, used for performing differential analysis on the amplified detection signal received by the first pin and the original detection signal received by the second pin, and then converting the differential signal into a digital signal;

[0044] The threshold comparison circuit is used to compare the converted digital signal with a first preset threshold.

[0045] In this embodiment, the AD sampling circuit 1031 can be implemented as an ADC differential sampling circuit. Since the signal output by the pyroelectric sensor has a relatively large stable DC bias, generally about 0.2 to 2V, regardless of whether it detects human movement, its output signal value is almost a stable DC voltage from the oscilloscope. The subsequent signal amplification and filtering circuit 102 only amplifies the AC signal, and the amplification factor is generally between 10 and 1000 times, but the DC level will not be amplified. Therefore, the amplified signal can be subtracted from the original detection signal and then compared with the first preset threshold, and human movement can also be determined. The first preset threshold can be different from the above preset threshold and can be set according to actual experience.

[0046] During implementation, the controller 103 may provide a first pin and a second pin, receive the amplified detection signal through the first pin, receive the original detection signal through the second pin, use the two signals as inputs of an ADC differential sampling circuit (for example: IN+ and IN-), output a valid digital detection signal, and input the threshold comparison circuit.

[0047] In another embodiment provided by the present disclosure, Figure 4 As shown, the AD sampling circuit 1031 includes: a first AD sampling circuit and a second AD sampling circuit; the threshold comparison module 1032 includes a threshold comparison circuit;

[0048] The second pin of the controller 103 is connected to the output end of the pyroelectric sensor 101; and the signal received by the second pin is transmitted to the second AD sampling circuit;

[0049] A first AD sampling circuit, used for converting the amplified detection signal received by the first pin into a first digital signal;

[0050] The threshold comparison circuit is used to compare the first digital signal with a second preset threshold.

[0051] In this embodiment, the AD sampling circuit 1031 can be implemented as a first AD sampling circuit and a second AD sampling circuit, and the first AD sampling circuit converts the amplified detection signal into a digital signal (for example, sampling ADC1) to obtain a first digital signal and compare it with a preset threshold. The signal collected by the second sampling circuit can be used in the subsequent micro-motion detection process.

[0052] In another embodiment provided by the present disclosure, Figure 5 As shown, the threshold comparison module 1032 includes a threshold comparison circuit;

[0053] The controller 103 is used to compare the amplified digital signal with a preset threshold value through a threshold comparison circuit.

[0054] Furthermore, since the analog signal generated by the pyroelectric sensor 101 is similar to a sinusoidal signal, the peak and trough of the signal can be used as a criterion for judging whether there is human movement. Therefore, the threshold comparison circuit can set preset thresholds for the peak and trough of the analog signal respectively. When the digital signal corresponding to the peak of the analog signal is greater than the corresponding preset threshold, or the digital signal corresponding to the trough of the analog signal is less than the corresponding preset threshold, it can be considered that the comparison result meets the preset condition. In addition, the preset threshold can be obtained based on experience and adjusted at any time according to the environment in which the sensor is located, which will not be repeated here.

[0055] In another embodiment provided by the present disclosure, the controller 103 is used to trigger an internal interrupt to wake up the processor when the comparison result meets a preset condition, so as to determine that human body movement occurs.

[0056] In this embodiment, the AD sampling circuit 1031 and the threshold comparison module 1032 can be integrated into the controller 103 and implemented through hardware circuits. In this way, only when the comparison result meets the preset conditions will the internal interrupt be triggered to wake up the processor in the controller 103. The processor determines whether human body movement occurs and makes a judgment on the presence of someone. The processor can be in a sleep state at other times, further reducing energy consumption.

[0057] In another embodiment provided by the present disclosure, the pyroelectric human body sensor further includes: a timer; the controller 103 further includes a processor; the processor includes a difference operation module;

[0058] A timer, configured to start timing after determining that a human body moves; and trigger an interrupt to wake up the processor whenever the timing time is reached;

[0059] The processor is used to perform difference calculation on the digital signal collected by the AD sampling circuit and the reference detection signal through the difference calculation module; and to perform human body micro-motion detection by analyzing and processing the obtained difference.

[0060] In the disclosed embodiment, after determining that human body movement has occurred, a timer can be started, and each time the timer is reached, the processor is triggered to wake up, so as to analyze and process the digital signal collected by the AD sampling circuit, and detect human body micro-movement. In other words, the AD sampling circuit can continuously collect and convert the amplified detection signal into a digital signal, and store it in the storage device of the controller and wait for the processor to be awakened and processed. After confirming that human body movement has occurred, the processor is awakened only when the timer is reached, and the digital signal collected by the AD sampling circuit is analyzed and processed to detect human body micro-movement.

[0061] It can be seen that Figure 2 The pyroelectric human body sensor in the related art shown can only sense large movements such as human body movement, but cannot identify movements with a smaller amplitude than the movement amplitude. The disclosed embodiment can analyze the smaller movements of the human body through digital signal analysis, and the signal detection is more precise and has a wider range of application scenarios, such as standing up, sitting down, raising hands, waving, raising legs, shaking heads, nodding, etc. The disclosure refers to movements with a smaller amplitude than large movements such as movement as micro-movements.

[0062] As mentioned above, since the signal output by the pyroelectric sensor has a relatively large stable DC bias, when performing micro-motion detection, the micro-motion is slight and the change in the detection signal is small and difficult to detect. In order to make the micro-motion detection more accurate, the DC bias can be removed to obtain an effective detection signal for further analysis and processing.

[0063] In the disclosed embodiment, a reference detection signal can be determined based on the original detection signal, and the difference between the digital signal and the reference detection signal can be determined to obtain an effective detection signal, and human micro-motion detection can be performed based on the effective detection signal. In a possible implementation, the controller 103 can also pre-record a digital signal corresponding to the detection signal representing that no one is moving (i.e., a digital signal obtained by analog-to-digital conversion of a signal level containing a DC component when "no one is moving" under normal circumstances), and use it as a reference detection signal.

[0064] In addition, when the signal level during “no human movement” may change, the digital signal corresponding to the detection signal representing no human movement stored in the controller 103 needs to be updated in time, for example, when the pyroelectric human body sensor is moved to a new environment.

[0065] In another embodiment provided by the present disclosure, Figure 6 As shown, the pyroelectric human body sensor further includes: a timer; the controller 103 further includes a processor; the processor includes a threshold comparison module 1032;

[0066] The timer is used to trigger an interrupt to wake up the processor whenever the timing time is reached;

[0067] The processor is used to compare the digital signal generated by the AD sampling circuit 1031 with a preset threshold through the threshold comparison module 1032 after being awakened, so as to determine that human body movement occurs when the comparison result meets the preset condition.

[0068] In this embodiment, the processor's judgment on human body movement can also be triggered by a timer interrupt. During implementation, a timer can be set, and a timing time can be pre-set. Whenever the timing time arrives, an interrupt is triggered to wake up the processor to judge human body movement. Accordingly, the processor only processes data when it is awakened when the timing time arrives.

[0069] Specifically, the AD sampling circuit can always collect the amplified detection signal and convert it into a digital signal, and the processor wakes up the processor when the timing time arrives. The processor compares the digital signal generated by the AD sampling circuit 1031 with the preset threshold through the threshold comparison module 1032, so as to determine that human movement occurs and make a judgment that there is a person when the comparison result meets the preset condition, or make a judgment that there is no person when the comparison result does not meet the preset condition. Regardless of the judgment result, the processor returns to the sleep state until it is awakened at the next timing time, and then analyzes and processes the data collected by the AD sampling circuit 1031. In this embodiment, the threshold comparison module 1032 performed by the processor can be implemented by hardware or by software.

[0070] In another embodiment provided by the present disclosure, the processor further includes a difference operation module 1033;

[0071] The processor is also used to perform a difference operation on the digital signal generated by the AD sampling circuit and the reference detection signal through the difference operation module 1033 after determining that human body movement has occurred and each time the timing time is reached and the processor is awakened, and to perform human body micro-movement detection by analyzing and processing the obtained difference.

[0072] In the embodiment of the present disclosure, when no human movement is detected, the timer can be used to wake up the processor to perform difference calculations and threshold comparisons to determine whether a person is moving. After determining that a person is present, the digital signal collected by the AD sampling circuit can be analyzed and processed to detect human body micro-movements.

[0073] In another embodiment provided by the present disclosure, the pyroelectric human body sensor further includes: a timer; the controller further includes a processor;

[0074] The timer is used to start timing after determining that a human body moves; and trigger an interrupt to wake up the processor whenever the timing time is reached;

[0075] The processor is used to detect human body micro-movement by analyzing and processing the digital signal converted after differentiation.

[0076] In the embodiment of the present disclosure, the controller 103 adopts an ADC differential sampling circuit. When a person moves, the timer starts to work, and the processor is woken up by the timer to perform difference calculation and threshold comparison, and the digital signal collected by the ADC differential sampling circuit is analyzed and processed to detect human body micro-movement.

[0077] Furthermore, since the ADC differential sampling circuit outputs the result of differentiating the amplified detection signal from the original detection signal, there is no need to set up a difference operation module, and there is no need to additionally determine a reference detection signal.

[0078] In another embodiment provided by the present disclosure, the pyroelectric human body sensor further includes: a timer; the controller further includes a processor; the processor includes a difference operation module 1033;

[0079] A timer, configured to start timing after determining that a human body moves; and trigger an interrupt to wake up the processor whenever the timing time is reached;

[0080] A second AD sampling circuit, used for converting the original detection signal received by the second pin into a second digital signal;

[0081] The processor is used to perform a difference operation on the first digital signal and the second digital signal through the difference operation module 1033; and perform human body micro-motion detection by analyzing and processing the obtained difference.

[0082] In the embodiment of the present disclosure, when a person moves, the timer starts timing, and whenever the timing time is reached, the interrupt wake-up processor is triggered to analyze and process the first digital signal obtained by the AD sampling circuit through the first AD sampling circuit and the second digital signal obtained by the second AD sampling circuit, thereby performing human body micro-motion detection. In this embodiment, there is no need to additionally determine the reference detection signal.

[0083] Furthermore, since obtaining the reference detection signal requires a certain amount of resources, for example, statistical measurement needs to be performed by software, and correction needs to be performed when the application environment changes, etc., Figure 3 , Figure 4 In the pyroelectric human body sensor shown, the original detection signal of the pyroelectric sensor is provided to the controller 103 for difference calculation with the amplified detection signal, which can omit the steps of determining and correcting the reference detection signal, and the effective detection signal obtained is more accurate, further saving resource consumption.

[0084] In addition, the method of performing human body micro-motion detection based on the obtained difference can refer to related technologies, such as setting corresponding thresholds for comparison, or performing further analysis and processing, etc., which will not be repeated here.

[0085] In another embodiment provided by the present disclosure, Figure 7 As shown, the signal amplification and filtering circuit 102 includes a single-stage amplification circuit;

[0086] The single-stage amplifier circuit includes: an operational amplifier OPA, a first feedback resistor R1, a first filter capacitor C1, a second feedback resistor R2, and a second filter capacitor C2;

[0087] Wherein, the non-inverting input terminal of the operational amplifier OPA is connected to the detection signal output S pole of the pyroelectric sensor 101;

[0088] The inverting input terminal of the operational amplifier OPA is respectively connected to one end of the first feedback resistor R1, one end of the second feedback resistor R2, and one end of the second filter capacitor C2; the other end of the first feedback resistor R1 is connected to one end of the first filter capacitor C1; the other end of the first filter capacitor C1 is grounded;

[0089] The output end of the operational amplifier OPA is connected to the first pin of the controller 103, the other end of the second feedback resistor R2, and the other end of the second filter capacitor C2 respectively.

[0090] This embodiment provides an implementation of the signal amplification and filtering circuit 102, and a connection relationship between the signal amplification and filtering circuit 102, the pyroelectric sensor 101 and the controller 103. Figure 2The pyroelectric sensor processing circuit shown uses four operational amplifiers in the circuit. Multi-stage amplification increases noise, consumes more current, and increases cost. In the embodiment of the present disclosure, only one operational amplifier is used to complete the amplification and filtering of the detection signal sent by the pyroelectric sensor, reducing the noise introduced by the latter stage of amplification. At the same time, since the number of operational amplifiers is reduced, the current overhead caused by multiple operational amplifiers is also eliminated.

[0091] In another embodiment provided by the present disclosure, Figure 8 As shown, the signal amplification and filtering circuit 102 includes a single-stage amplification circuit;

[0092] The single-stage amplifier circuit includes: an operational amplifier OPA, a first feedback resistor R1, a first filter capacitor C1, a second feedback resistor R2, and a second filter capacitor C2;

[0093] Wherein, the non-inverting input terminal of the operational amplifier OPA is connected to the detection signal output S pole of the pyroelectric sensor 101;

[0094] The inverting input terminal of the operational amplifier OPA is respectively connected to one end of the first feedback resistor R1, one end of the second feedback resistor R2, and one end of the second filter capacitor C2; the other end of the first feedback resistor R1 is connected to one end of the first filter capacitor C1; the other end of the first filter capacitor C1 is grounded;

[0095] The output end of the operational amplifier OPA is respectively connected to the first pin of the controller 103, the other end of the second feedback resistor R2, and the other end of the second filter capacitor C2;

[0096] The detection signal output S pole of the pyroelectric sensor 101 is connected to the second pin of the controller 103 .

[0097] In this embodiment, the controller 103 provides two pins, which are respectively used to receive the amplified detection signal and the original detection signal of the pyroelectric sensor 101, so as to subsequently determine the difference between the two signals.

[0098] against Figure 7 and Figure 8 In the provided implementation mode, in the single-stage amplifier circuit OPA, the amplification ratio of the input signal is determined based on the resistance value of the first feedback resistor R1, the resistance value of the second feedback resistor R2, the capacitance value of the first filter capacitor C1, and the capacitance value of the second filter capacitor C2. It can be set according to the principle of the amplifier circuit and actual needs, and will not be repeated here.

[0099] In another embodiment provided by the present disclosure, the controller 103 is further configured to control the processor to continue to remain in the sleep state when the comparison result does not meet a preset condition.

[0100] In this embodiment, since the comparison and analysis of the digital signal is implemented by a hardware circuit, the processor is awakened only when the comparison result meets the preset condition. When the comparison result does not meet the preset condition, the processor can remain in a dormant state, saving power consumption.

[0101] In another embodiment provided by the present disclosure, the processor is further configured to enter a sleep state after performing human motion detection; human motion detection includes: human movement and / or human micro-movement.

[0102] In this embodiment, the processor returns to the sleep state after completing the human motion detection until being awakened by the next timer timing.

[0103] A pyroelectric human body sensor provided by the embodiment of the present disclosure processes detection signals through an AD sampling circuit 1031 and a threshold comparison module 1032 integrated inside a controller, which can simplify the external circuit design and reduce the power consumption of the sensor.

[0104] Those skilled in the art can understand that the accompanying drawings are only schematic diagrams of a preferred embodiment, and the modules in the accompanying drawings are not necessarily required for implementing the present disclosure.

[0105] Those skilled in the art can understand that the circuits in the embodiments can be distributed in the devices of the embodiments according to the description of the embodiments, or can be located in one or more devices different from the embodiments with corresponding changes. The circuits in the above embodiments can be combined into one circuit, or can be further divided into multiple sub-circuits.

[0106] The above description order of the embodiments of the present disclosure is for description only and does not represent the advantages or disadvantages of the embodiments.

[0107] Obviously, those skilled in the art can make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is also intended to include these modifications and variations.

Claims

1. A pyroelectric human body sensor, characterized in that: include: A pyroelectric sensor, a signal amplification and filtering circuit, and a controller; the controller includes: an AD sampling circuit and a threshold comparison module; Wherein, the input end of the signal amplifying and filtering circuit is connected to the output end of the pyroelectric sensor, and is used to receive the detection signal sent by the pyroelectric sensor and amplify the detection signal; The first pin of the controller is connected to the output end of the signal amplification and filtering circuit, and is used to receive the amplified detection signal; The AD sampling circuit is used to generate a digital signal based on the amplified detection signal; The threshold comparison module is used to compare the digital signal with a preset threshold to determine that human body movement occurs when the comparison result meets a preset condition.

2. The sensor according to claim 1, characterized in that The AD sampling circuit includes an ADC differential sampling circuit; the threshold comparison module includes a threshold comparison circuit; The second pin of the controller is connected to the output end of the pyroelectric sensor; The ADC differential sampling circuit is used to differentiate the amplified detection signal received by the first pin from the original detection signal received by the second pin, and then convert the differentiated signal into a digital signal; The threshold comparison circuit is used to compare the converted digital signal with a first preset threshold.

3. The sensor according to claim 1, characterized in that The AD sampling circuit includes: a first AD sampling circuit and a second AD sampling circuit; the threshold comparison module includes a threshold comparison circuit; The second pin of the controller is connected to the output end of the pyroelectric sensor; and the signal received by the second pin is transmitted to the second AD sampling circuit; The first AD sampling circuit is used to convert the amplified detection signal received by the first pin into a first digital signal; The threshold comparison circuit is used to compare the first digital signal with a preset threshold.

4. The sensor according to claim 1, characterized in that The controller is used to trigger an internal interrupt to wake up the processor when the comparison result meets a preset condition, so as to determine that human body movement occurs.

5. The sensor according to claim 1, characterized in that Also includes: Timer; The controller further comprises a processor; the processor comprises a threshold comparison module; The timer is used to trigger an interrupt to wake up the processor whenever the timing time is reached; The processor is used to compare the digital signal generated by the AD sampling circuit with a preset threshold through the threshold comparison module after being awakened, so as to determine that human body movement occurs when the comparison result meets a preset condition.

6. The sensor according to claim 5, characterized in that The processor further includes a difference operation module; The processor is also used to perform a difference operation on the digital signal generated by the AD sampling circuit and the reference detection signal through the difference operation module after determining that human body movement has occurred, and perform human body micro-movement detection by analyzing and processing the obtained difference each time the timing time is reached and the processor is awakened.

7. The sensor according to claim 4, characterized in that Also includes: Timer; The controller further comprises a processor; the processor comprises a difference operation module; The timer is used to start timing after determining that a human body moves; and trigger an interrupt to wake up the processor whenever the timing time is reached; The processor is used to perform a difference operation on the digital signal collected by the AD sampling circuit and the reference detection signal through the difference operation module; and perform human body micro-motion detection by analyzing and processing the obtained difference.

8. The sensor according to claim 2, characterized in that: Also includes: timer; the controller also includes a processor; The timer is used to start timing after determining that a human body moves; and trigger an interrupt to wake up the processor whenever the timing time is reached; The processor is used to detect human body micro-movement by analyzing and processing the digital signal converted after differentiation.

9. The sensor according to claim 3, characterized in that: Also includes: Timer; The controller further comprises a processor; the processor comprises a difference operation module; The timer is used to start timing after determining that a human body moves; and trigger an interrupt to wake up the processor whenever the timing time is reached; The second AD sampling circuit is used to convert the original detection signal received by the second pin into a second digital signal; The processor is used to perform a difference operation on the first digital signal and the second digital signal through the difference operation module; and perform human body micro-movement detection by analyzing and processing the obtained difference.

10. The sensor according to claim 1, 4, 5, 6 or 7, characterized in that: The signal amplification and filtering circuit includes a single-stage amplification circuit; The single-stage amplifier circuit includes: an operational amplifier OPA, a first feedback resistor R1, a first filter capacitor C1, a second feedback resistor R2, and a second filter capacitor C2; Wherein, the non-inverting input terminal of the operational amplifier OPA is connected to the detection signal output S pole of the pyroelectric sensor; The inverting input terminal of the operational amplifier OPA is respectively connected to one end of the first feedback resistor R1, one end of the second feedback resistor R2, and one end of the second filter capacitor C2; the other end of the first feedback resistor R1 is connected to one end of the first filter capacitor C1; the other end of the first filter capacitor C1 is grounded; The output end of the operational amplifier OPA is respectively connected to the first pin of the controller, the other end of the second feedback resistor R2, and the other end of the second filter capacitor C2.

11. The sensor according to claim 2, 3, 8 or 9, characterized in that: The signal amplification and filtering circuit includes a single-stage amplification circuit; The single-stage amplifier circuit includes: an operational amplifier OPA, a first feedback resistor R1, a first filter capacitor C1, a second feedback resistor R2, and a second filter capacitor C2; Wherein, the non-inverting input terminal of the operational amplifier OPA is connected to the detection signal output S pole of the pyroelectric sensor; The inverting input terminal of the operational amplifier OPA is respectively connected to one end of the first feedback resistor R1, one end of the second feedback resistor R2, and one end of the second filter capacitor C2; the other end of the first feedback resistor R1 is connected to one end of the first filter capacitor C1; the other end of the first filter capacitor C1 is grounded; The output end of the operational amplifier OPA is respectively connected to the first pin of the controller, the other end of the second feedback resistor R2, and the other end of the second filter capacitor C2; The detection signal output S pole of the pyroelectric sensor is connected to the second pin of the controller.

12. The sensor according to claim 4, characterized in that The controller is further configured to control the processor to continue to remain in a dormant state when the comparison result does not satisfy a preset condition.

13. The sensor according to any one of claims 5 to 9, characterized in that: The processor is further used to enter a dormant state after performing human motion detection; human motion detection includes: human movement and / or human micro-motion.

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