Measuring circuit of capacitive sensor

Abstract

The utility model discloses a measuring circuit of a capacitive sensor, which relates to the technical field of capacitive sensors and comprises a power supply module used for supplying power; the capacitive sensor module is used for converting the change of the capacitance into an electric signal; the trigger module is used for setting a voltage threshold value and controlling the signal transmission module to perform signal transmission in a delayed manner when the electric signal is greater than the voltage threshold value, and controlling the electric energy control module to provide electric energy for the signal processing module in a delayed manner; the signal processing module is used for carrying out signal amplification and filtering processing on the input electric signal; and the signal receiving module is used for receiving and storing the signal output by the signal processing module. The measuring circuit of the capacitive sensor is detected by the capacitive sensor module and converts the change of capacitance into an electric signal, when the electric signal is greater than a voltage threshold set by the trigger module, the trigger signal processing module automatically amplifies and filters the electric signal, and then the electric signal is received by the signal receiving module.

Description

Technical Field

[0001] The utility model relates to the technical field of capacitive sensors, in particular to a measuring circuit of a capacitive sensor. Background Art

[0002] A capacitive sensor is a conversion device that uses various types of capacitors as sensing elements to convert the measured physical or mechanical quantity into a change in capacitance. It is widely used in the measurement of displacement, angle, vibration, speed, pressure, component analysis, and dielectric properties. The output signal is processed by an amplifying and filtering circuit composed of an operational amplifier to improve the accuracy of the detection signal. However, in order to record the changing state of the capacitive sensor at all times, the amplifying and filtering circuit needs to remain in working condition for a long time, which results in a large loss of electrical energy, increases the data processing burden of the processor, and reduces the service life of the amplifying and filtering circuit. Therefore, it needs to be improved. Utility Model Content

[0003] The embodiment of the utility model provides a measurement circuit of a capacitive sensor to solve the problems raised in the above background technology.

[0004] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0005] A measuring circuit of a capacitive sensor comprises: a power supply module, a capacitive sensor module, a trigger module, a signal transmission module, an electric energy control module, a signal processing module and a signal receiving module;

[0006] A power module is used to access direct current power and perform voltage stabilization and filtering on the direct current power;

[0007] A capacitive sensor module, connected to the power module, for receiving the electric energy processed by the power module and converting the change of electric capacitance into an electric signal and outputting a first detection signal;

[0008] A trigger module, connected to the capacitive sensor module, for setting a voltage threshold and delaying output of a first control signal when the first detection signal is greater than the voltage threshold;

[0009] A signal transmission module, connected to the capacitive sensor module, the trigger module and the signal processing module, and configured to receive the first control signal and transmit the first detection signal to the signal processing module;

[0010] an electric energy control module, connected to the trigger module, the power module and the signal processing module, and configured to receive the first control signal and transmit the electric energy processed by the power module to the signal processing module;

[0011] A signal processing module, used for receiving the electric energy transmitted by the electric energy control module and performing signal amplification and filtering processing on the input first detection signal;

[0012] The signal receiving module is connected to the signal processing module and is used to receive and store the signal output by the signal processing module.

[0013] As a further solution of the utility model: the power module includes a power interface, a first capacitor, a first voltage regulator and a second capacitor; the capacitive sensor module includes a capacitive sensor;

[0014] Preferably, the first end of the power interface is connected to one end of the first capacitor and the third end of the first voltage regulator, the second end of the first voltage regulator is connected to one end of the second capacitor and the power end of the capacitive sensor, the second end of the power interface, the other end of the first capacitor, the first end of the first voltage regulator, the other end of the second capacitor and the ground end of the capacitive sensor are all grounded, and the output end of the capacitive sensor is connected to the trigger module and the signal transmission module.

[0015] As a further solution of the utility model: the signal transmission module includes a first analog switch;

[0016] Preferably, the IN terminal of the first analog switch is connected to the output terminal of the capacitive sensor, the OUT terminal of the first analog switch is connected to the signal processing module, and the CTRL terminal of the first analog switch is connected to the trigger module.

[0017] As a further solution of the utility model: the trigger module includes a first potentiometer, a first diode, a second diode, a fifth capacitor, a tenth resistor, an eleventh resistor, a second switch tube and a first power supply;

[0018] Preferably, one end of the first potentiometer is connected to the output end of the capacitive sensor, the other end of the first potentiometer and the slider end are both connected to the cathode of the first diode, the anode of the first diode is connected to the anode of the second diode, the cathode of the second diode is connected to one end of the fifth capacitor, one end of the tenth resistor and the base of the second switch tube, the emitter of the second switch tube is connected to the CTRL end of the first analog switch and the power control module and is grounded through the eleventh resistor, the other end of the tenth resistor and the other end of the fifth capacitor are both grounded, and the collector of the second switch tube is connected to the first power supply.

[0019] As a further solution of the utility model: the power control module includes a ninth resistor, a first power tube and a first switch tube;

[0020] Preferably, the gate of the first power tube is connected to the collector of the first switching tube and is connected to the source of the first power tube and the second end of the first regulator through a ninth resistor, the emitter of the first switching tube is grounded, the base of the first switching tube is connected to the emitter of the second switching tube and the CTRL end of the first analog switch, and the drain of the first power tube is connected to the signal processing module.

[0021] As a further solution of the utility model: the signal processing module includes a first resistor, a third capacitor, a second resistor, a fourth capacitor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a first operational amplifier; the signal receiving module includes a first controller;

[0022] Preferably, the in-phase end of the first operational amplifier is connected to one end of the fourth capacitor and one end of the fifth resistor and is connected to one end of the first resistor, one end of the third capacitor and the OUT end of the first analog switch through the second resistor; the inverting end of the first operational amplifier is connected to one end of the third resistor and is connected to the drain of the first power tube, the first power supply end of the first operational amplifier and one end of the seventh resistor through the fourth resistor; the other end of the seventh resistor is connected to the output end of the first operational amplifier and the IO1 end of the first controller and is connected to one end of the sixth resistor and the other end of the fifth resistor through the eighth resistor; the other end of the sixth resistor, the second power supply end of the first operational amplifier, the other end of the third resistor, the other end of the fourth capacitor, the other end of the third capacitor and the other end of the first resistor are all grounded.

[0023] Compared with the prior art, the beneficial effects of the utility model are as follows: the measuring circuit of the capacitive sensor of the utility model is detected by the capacitive sensor module and converts the change of capacitance into an electrical signal. At the same time, when the converted electrical signal is greater than the voltage threshold set by the trigger module, the signal transmission module is automatically controlled to perform signal transmission work, and the power control module is controlled to perform power transmission work, so as to trigger the signal processing module to automatically perform signal amplification and filtering processing, and finally the signal is received by the signal receiving module, thereby reducing the power consumption of the measuring circuit, reducing the data processing burden of the processor, and improving the service life of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the description of the embodiments of the utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0025] Figure 1 The present invention provides a schematic block diagram of a measuring circuit of a capacitive sensor.

[0026] Figure 2 A circuit diagram of a measuring circuit of a capacitive sensor provided in an example of the utility model.

[0027] Figure 3 This is a connection circuit diagram of a trigger module provided in an example of the utility model. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] In one embodiment, see Figure 1 , a measuring circuit of a capacitive sensor, comprising: a power supply module 1, a capacitive sensor module 2, a trigger module 3, a signal transmission module 4, a power control module 5, a signal processing module 6 and a signal receiving module 7;

[0030] Specifically, the power module 1 is used to access direct current power and perform voltage stabilization and filtering on the direct current power;

[0031] The capacitive sensor module 2 is connected to the power module 1 and is used to receive the electric energy processed by the power module 1 and convert the change of the electric capacity into an electric signal and output a first detection signal;

[0032] A trigger module 3, connected to the capacitive sensor module 2, for setting a voltage threshold and delaying output of a first control signal when the first detection signal is greater than the voltage threshold;

[0033] A signal transmission module 4, connected to the capacitive sensor module 2, the trigger module 3 and the signal processing module 6, for receiving the first control signal and transmitting the first detection signal to the signal processing module 6;

[0034] The power control module 5 is connected to the trigger module 3, the power module 1 and the signal processing module 6, and is used to receive the first control signal and transmit the power processed by the power module 1 to the signal processing module 6;

[0035] The signal processing module 6 is used to receive the electric energy transmitted by the electric energy control module 5 and perform signal amplification and filtering processing on the input first detection signal;

[0036] The signal receiving module 7 is connected to the signal processing module 6 and is used to receive and store the signal output by the signal processing module 6 .

[0037] In a specific embodiment, the power supply module 1 may adopt a power supply circuit composed of a power supply interface, a voltage stabilizer, a capacitor, etc., may be connected to DC power and perform voltage stabilization and filtering on the DC power; the capacitive sensor module 2 may adopt a capacitive sensor circuit composed of a capacitive sensor, which may convert the change in capacitance into an electrical signal and output it; the trigger module 3 may adopt a trigger circuit composed of a potentiometer, a diode, a triode, a capacitor, etc., may set a voltage threshold, and control the working state of the signal transmission module 4 and the power control module 5 according to the relationship between the voltage threshold and the size of the electrical signal; the signal transmission module 4 may adopt a signal transmission circuit composed of an analog switch, which may transmit the input electrical signal; the power control module 5 may adopt a power control circuit composed of a power tube, a triode and a resistor to control the transmission state of the electrical energy; the signal processing module 6 may adopt a signal processing circuit composed of an operational amplifier, a resistor, a capacitor, etc., to amplify and filter the input signal; the signal receiving module 7 may adopt a signal receiving module 7 composed of a single-chip microcomputer to receive and store signals.

[0038] In another embodiment, see Figure 1 , Figure 2 and Figure 3 , the power module 1 includes a power interface, a first capacitor C1, a first regulator IC1 and a second capacitor C2; the capacitive sensor module 2 includes a capacitive sensor;

[0039] Specifically, the first end of the power interface is connected to one end of the first capacitor C1 and the third end of the first voltage regulator IC1, the second end of the first voltage regulator IC1 is connected to one end of the second capacitor C2 and the power end of the capacitive sensor, the second end of the power interface, the other end of the first capacitor C1, the first end of the first voltage regulator IC1, the other end of the second capacitor C2 and the ground end of the capacitive sensor are all grounded, and the output end of the capacitive sensor is connected to the trigger module 3 and the signal transmission module 4.

[0040] In a specific embodiment, the first voltage regulator IC1 may be a 78XX series voltage regulator for voltage stabilization.

[0041] Further, the signal transmission module 4 includes a first analog switch U2;

[0042] Specifically, the IN terminal of the first analog switch U2 is connected to the output terminal of the capacitive sensor, the OUT terminal of the first analog switch U2 is connected to the signal processing module 6 , and the CTRL terminal of the first analog switch U2 is connected to the trigger module 3 .

[0043] In a specific embodiment, the first analog switch U2 can be a CD4066 analog switch.

[0044] Further, the trigger module 3 includes a first potentiometer RP1, a first diode D1, a second diode D2, a fifth capacitor C5, a tenth resistor R10, an eleventh resistor R11, a second switch tube VT2 and a first power supply VCC1;

[0045] Specifically, one end of the first potentiometer RP1 is connected to the output end of the capacitive sensor, the other end of the first potentiometer RP1 and the slider end are both connected to the cathode of the first diode D1, the anode of the first diode D1 is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to one end of the fifth capacitor C5, one end of the tenth resistor R10 and the base of the second switch tube VT2, the emitter of the second switch tube VT2 is connected to the CTRL end of the first analog switch U2 and the power control module 5 and is grounded through the eleventh resistor R11, the other end of the tenth resistor R10 and the other end of the fifth capacitor C5 are both grounded, and the collector of the second switch tube VT2 is connected to the first power supply VCC1.

[0046] In a specific embodiment, the first potentiometer RP1 and the first diode D1 set the voltage threshold, which can prevent the first analog switch U2 from transmitting the low micro-electric signal generated by the capacitive sensor; the fifth capacitor C5 stores energy and cooperates with the tenth resistor R10 to control the delayed conduction of the second switch tube VT2; the second switch tube VT2 can be an NPN transistor.

[0047] Furthermore, the power control module 5 includes a ninth resistor R9, a first power tube Q1 and a first switch tube VT1;

[0048] Specifically, the gate of the first power tube Q1 is connected to the collector of the first switch tube VT1 and is connected to the source of the first power tube Q1 and the second end of the first regulator IC1 through the ninth resistor R9, the emitter of the first switch tube VT1 is grounded, the base of the first switch tube VT1 is connected to the emitter of the second switch tube VT2 and the CTRL end of the first analog switch U2, and the drain of the first power tube Q1 is connected to the signal processing module 6.

[0049] In a specific embodiment, the first power tube Q1 may be a P-channel field effect tube, which is controlled and cut off by the electric energy input by the ninth resistor R9; the first switch tube VT1 may be an NPN transistor, which controls the conduction of the first power tube Q1.

[0050] Further, the signal processing module 6 includes a first resistor R1, a third capacitor C3, a second resistor R2, a fourth capacitor C4, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a first operational amplifier OP1; the signal receiving module 7 includes a first controller U1;

[0051] Specifically, the in-phase end of the first operational amplifier OP1 is connected to one end of the fourth capacitor C4 and one end of the fifth resistor R5, and is connected to one end of the first resistor R1, one end of the third capacitor C3 and the OUT end of the first analog switch U2 through the second resistor R2. The inverting end of the first operational amplifier OP1 is connected to one end of the third resistor R3 and is connected to the drain of the first power tube Q1, the first power supply VCC1 end of the first operational amplifier OP1 and one end of the seventh resistor R7 through the fourth resistor R4. The other end of the seventh resistor R7 is connected to the output end of the first operational amplifier OP1 and the IO1 end of the first controller U1 and is connected to one end of the sixth resistor R6 and the other end of the fifth resistor R5 through the eighth resistor R8. The other end of the sixth resistor R6, the second power supply end of the first operational amplifier OP1, the other end of the third resistor R3, the other end of the fourth capacitor C4, the other end of the third capacitor C3 and the other end of the first resistor R1 are all grounded.

[0052] In a specific embodiment, the first operational amplifier OP1 may use an LM393 operational amplifier to cooperate with the first resistor R1, the third capacitor C3, the second resistor R2, the fourth capacitor C4, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7 and the eighth resistor R8 to perform signal amplification and filtering processing; the first controller U1 may use an STM32 microcontroller to receive signals.

[0053] In a measuring circuit of a capacitive sensor of the present embodiment, a power interface is connected to direct current power, and a first voltage regulator IC1, a first capacitor C1, and a second capacitor C2 perform voltage stabilization and filtering. At this time, the capacitive sensor performs detection and converts the change of capacitance into an electrical signal. Only when the electrical signal is greater than the voltage threshold set by the first potentiometer RP1 and the first diode D1, the first diode D1 is broken down and stored by the fifth capacitor C5, triggering the second switch tube VT2 to turn on. At this time, the first power supply VCC1 triggers the first switch tube VT1 to turn on through the second switch tube VT2 and the eleventh resistor R11, triggering the first analog switch U2 to transmit the signal, the first power tube Q1 is turned off, and the first operational amplifier OP1 is powered on and starts to work. The transmitted electrical signal is amplified and filtered by the first operational amplifier OP1 in cooperation with the first resistor R1, the third capacitor C3, the second resistor R2, the fourth capacitor C4, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, and the eighth resistor R8, and is finally received and stored by the first controller U1.

[0054] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0055] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A measuring circuit for a capacitive sensor, characterized in that: The measuring circuit of the capacitive sensor comprises: a power supply module, a capacitive sensor module, a trigger module, a signal transmission module, an electric energy control module, a signal processing module and a signal receiving module; The power supply module is used to receive direct current power and perform voltage stabilization and filtering on the direct current power; The capacitive sensor module is connected to the power module, and is used to receive the electric energy processed by the power module and convert the change of the electric capacity into an electric signal and output a first detection signal; The trigger module is connected to the capacitive sensor module and is used to set a voltage threshold and delay output of a first control signal when the first detection signal is greater than the voltage threshold; The signal transmission module is connected to the capacitive sensor module, the trigger module and the signal processing module, and is used to receive the first control signal and transmit the first detection signal to the signal processing module; The power control module is connected to the trigger module, the power module and the signal processing module, and is used to receive the first control signal and transmit the power processed by the power module to the signal processing module; The signal processing module is used to receive the electric energy transmitted by the electric energy control module and perform signal amplification and filtering processing on the input first detection signal; The signal receiving module is connected to the signal processing module and is used to receive and store the signal output by the signal processing module.

2. A measuring circuit for a capacitive sensor according to claim 1, characterized in that: The power module includes a power interface, a first capacitor, a first voltage regulator and a second capacitor; the capacitive sensor module includes a capacitive sensor; The first end of the power interface is connected to one end of the first capacitor and the third end of the first regulator, the second end of the first regulator is connected to one end of the second capacitor and the power end of the capacitive sensor, the second end of the power interface, the other end of the first capacitor, the first end of the first regulator, the other end of the second capacitor and the ground end of the capacitive sensor are all grounded, and the output end of the capacitive sensor is connected to the trigger module and the signal transmission module.

3. A measuring circuit for a capacitive sensor according to claim 2, characterized in that: The signal transmission module includes a first analog switch; The IN terminal of the first analog switch is connected to the output terminal of the capacitive sensor, the OUT terminal of the first analog switch is connected to the signal processing module, and the CTRL terminal of the first analog switch is connected to the trigger module.

4. A measuring circuit for a capacitive sensor according to claim 3, characterized in that: The trigger module includes a first potentiometer, a first diode, a second diode, a fifth capacitor, a tenth resistor, an eleventh resistor, a second switch tube and a first power supply; One end of the first potentiometer is connected to the output end of the capacitive sensor, the other end of the first potentiometer and the slider end are both connected to the cathode of the first diode, the anode of the first diode is connected to the anode of the second diode, the cathode of the second diode is connected to one end of the fifth capacitor, one end of the tenth resistor and the base of the second switch tube, the emitter of the second switch tube is connected to the CTRL end of the first analog switch and the power control module and is grounded through the eleventh resistor, the other end of the tenth resistor and the other end of the fifth capacitor are both grounded, and the collector of the second switch tube is connected to the first power supply.

5. A measuring circuit for a capacitive sensor according to claim 4, characterized in that: The power control module includes a ninth resistor, a first power tube and a first switch tube; The gate of the first power tube is connected to the collector of the first switch tube and is connected to the source of the first power tube and the second end of the first regulator through a ninth resistor, the emitter of the first switch tube is grounded, the base of the first switch tube is connected to the emitter of the second switch tube and the CTRL end of the first analog switch, and the drain of the first power tube is connected to the signal processing module.

6. A measuring circuit for a capacitive sensor according to claim 5, characterized in that: The signal processing module includes a first resistor, a third capacitor, a second resistor, a fourth capacitor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a first operational amplifier; the signal receiving module includes a first controller; The in-phase end of the first operational amplifier is connected to one end of the fourth capacitor and one end of the fifth resistor, and is connected to one end of the first resistor, one end of the third capacitor and the OUT end of the first analog switch through the second resistor. The inverting end of the first operational amplifier is connected to one end of the third resistor and is connected to the drain of the first power tube, the first power supply end of the first operational amplifier and one end of the seventh resistor through the fourth resistor. The other end of the seventh resistor is connected to the output end of the first operational amplifier and the IO1 end of the first controller, and is connected to one end of the sixth resistor and the other end of the fifth resistor through the eighth resistor. The other end of the sixth resistor, the second power supply end of the first operational amplifier, the other end of the third resistor, the other end of the fourth capacitor, the other end of the third capacitor and the other end of the first resistor are all grounded.

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