A capacitive sensor test system
The testing system, composed of a capacitance detection chip, a microcontroller, and a host computer, solves the problems of low accuracy and high complexity in existing capacitance detection circuits, and realizes high-precision, low-cost capacitance sensor testing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHENZHEN ZHONGYANXIN ELECTRONICS CO LTD
- Filing Date
- 2025-06-20
- Publication Date
- 2026-05-29
AI Technical Summary
Existing capacitance detection circuits can only detect capacitive sensors at the picofarad (pF) level, resulting in low detection accuracy, high cost, and complex configuration.
The testing system consists of a capacitance detection chip, a microcontroller, and a host computer. The capacitance detection chip converts the capacitance signal under test into a voltage signal, the microcontroller converts the voltage signal into a digital signal, and the host computer processes the data to achieve high-speed data acquisition.
It improves the testing accuracy of capacitive sensors, reduces the complexity of system configuration, and has a lower cost.
Smart Images
Figure CN224303072U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of detection technology, and in particular to a capacitive sensor testing system. Background Technology
[0002] Capacitive sensors are widely used in environmental monitoring, industrial automation, aerospace and other fields. They are sensors that convert changes in the measured physical quantity into changes in capacitance.
[0003] The magnitude of the capacitance change is related to the measurement accuracy of the capacitive sensor. The measurement accuracy of the capacitive sensor directly affects the accuracy of the final measurement result, so it is necessary to test the measurement accuracy of the capacitive sensor.
[0004] Currently, capacitance detection circuits are generally used to detect the measurement accuracy of capacitive sensors. However, existing capacitance detection circuits can only detect capacitive sensors at the picofarad (pF) level, resulting in problems such as low detection accuracy, high cost, and complex configuration. Utility Model Content
[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide a capacitive sensor testing system.
[0006] This utility model provides a capacitive sensor testing system, which includes: a capacitance detection chip, a microcontroller, and a host computer;
[0007] The microcontroller is connected to the capacitance detection chip and the host computer respectively.
[0008] The capacitance detection chip is used to acquire the capacitance signal to be tested, convert the capacitance signal to be tested into a voltage signal to be tested, and send the voltage signal to be tested to the microcontroller.
[0009] The microcontroller is used to convert the received voltage signal to be measured into a digital signal to be measured, and to send the digital signal to be measured to the host computer;
[0010] The host computer is used to process the digital signal to be tested.
[0011] In one possible implementation, the microcontroller connects to the capacitance detection chip via I / O ports.
[0012] In one possible implementation, the microcontroller integrates a serial interface, and the microcontroller connects to the host computer through the serial interface and a level conversion chip.
[0013] In one possible implementation, the capacitance detection chip is provided with multiple ports for connecting to a capacitive sensor to obtain the capacitance signal to be measured.
[0014] In one possible implementation, the microcontroller has a built-in A / D converter, which is used to convert the voltage signal to be measured into a digital signal to be measured.
[0015] In one possible implementation, the A / D converter is a 12-bit A / D converter.
[0016] In one possible implementation, the A / D converter uses an internal reference voltage or an external reference voltage.
[0017] In one possible implementation, the internal reference voltage is 2.5V or 2.25V.
[0018] In one possible implementation, the capacitance detection chip is model MS3110, and the microcontroller is model MSP430F149.
[0019] In one possible implementation, the system further includes a power supply module, which is connected to the microcontroller and the capacitance detection chip respectively, and the power supply module is used to supply power to the microcontroller and the capacitance detection chip.
[0020] This embodiment of the invention provides a capacitive sensor testing system. The system employs a capacitance detection chip, a microcontroller, and a host computer. The capacitance detection chip converts the acquired capacitance signal into a voltage signal and sends it to the microcontroller. The microcontroller then converts the voltage signal into a digital signal, which is further processed by the host computer. This capacitive sensor testing system enables high-speed data acquisition, has high testing accuracy, and is simple to configure. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.
[0022] Figure 1 This is a schematic diagram of the capacitive sensor testing system in an embodiment of the present invention;
[0023] Figure 2 This is another schematic diagram of the capacitive sensor testing system in this embodiment of the present invention;
[0024] Figure 3 This is a circuit diagram of the capacitance acquisition of the capacitance detection chip in an embodiment of this utility model;
[0025] Figure 4This is a data processing and operation circuit diagram of the microcontroller in this embodiment of the utility model;
[0026] Figure 5 This is a schematic diagram of the input and output in an embodiment of the present utility model;
[0027] Figure 6a This is a circuit test diagram in an embodiment of the present utility model;
[0028] Figure 6b This is a circuit test diagram in an embodiment of the present utility model;
[0029] Figure 7 This is a graph showing the capacitance test data in an embodiment of this utility model;
[0030] Figure 8 This is another schematic diagram of the capacitive sensor testing system in this embodiment of the present invention;
[0031] Figure 9 This is a circuit diagram of the power module in an embodiment of the present utility model.
[0032] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0033] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.
[0034] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0035] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0036] In existing technologies, capacitance detection circuits are generally used to detect the measurement accuracy of capacitive sensors. However, these methods can only detect capacitive sensors at the picofarad (pF) level, and have problems such as low detection accuracy, high cost, and complex configuration.
[0037] See Figure 1 , Figure 1 A schematic diagram of a capacitive sensor testing system provided in an embodiment of the present invention is shown. The capacitive sensor testing system includes: a capacitance detection chip 10, a microcontroller 20, and a host computer 30, wherein the microcontroller 20 is connected to the capacitance detection chip 10 and the host computer 30 respectively.
[0038] Specifically, the capacitance detection chip 10 is used to acquire the capacitance signal to be tested, convert the capacitance signal to be tested into a voltage signal to be tested, and send the voltage signal to be tested to the microcontroller 20; the microcontroller 20 is used to convert the received voltage signal to be tested into a digital signal to be tested, and send the digital signal to be tested to the host computer 30; the host computer 30 is used to process the digital signal to be tested.
[0039] In this system, the output signal of a capacitive sensor is typically the change in capacitance; that is, the capacitive sensor outputs a capacitance signal, and the capacitance signal acquired by the capacitance detection chip 10 from the capacitive sensor is the capacitance signal to be measured. Within the capacitance detection chip 10, the capacitance signal to be measured is converted into a voltage signal to be measured, which is an analog signal. It is understood that converting a capacitance signal into a voltage signal can be achieved using existing technology, the details of which will not be elaborated here.
[0040] Before data transmission between the microcontroller 20 and the capacitance detection chip 10, the capacitance detection chip 10 can be initialized to ensure its accurate and stable operation. For example, parameters such as the reference capacitance value, adjustable gain, and initial voltage of the capacitance detection chip 10 can be initialized.
[0041] In addition, the microcontroller 20 can be initialized to ensure stable operation of the test system. Microcontroller initialization generally includes: microcontroller I / O initialization, serial interface parameter initialization, A / D converter initialization, and communication and reception system parameters between the microcontroller and the host computer.
[0042] After sampling begins (data transmission between the microcontroller 20 and the capacitance detection chip 10 starts), the microcontroller 20 samples the voltage signal to be measured according to the set sampling rate. After sampling is complete, the microcontroller 20 converts the sampled voltage signal to be measured into a digital signal and transmits the digital signal to the host computer 30. The host computer 30 processes the data uploaded by the microcontroller 20 and sends instructions to the microcontroller 20, which then performs the corresponding actions according to the instructions. It can be understood that the microcontroller converts the voltage signal to be measured into a digital signal, which facilitates subsequent data processing by the host computer.
[0043] Furthermore, the host computer software can be written in C#. Its functions include setting parameters, communicating with the slave computer, and real-time graphical display, storage, and retrieval of data. The host computer software mainly consists of a communication module, a human-computer interface module, and a database module. Therefore, the host computer can analyze, display, and store the digital signals under test, allowing users to obtain the test results of the capacitive sensor based on the information displayed on the host computer.
[0044] like Figure 2 As shown, Figure 2 Another schematic diagram of the capacitive sensor testing system provided in this embodiment of the present invention is shown. In this embodiment, the capacitance detection chip 10 is model MS3110, and the microcontroller 20 is model MSP430F149.
[0045] Specifically, the MS3110 capacitance sensing chip uses a complementary metal-oxide-semiconductor (CMOS) process, operates at +5V, and has a measurement sensitivity of 8aF. Furthermore, the MS3110 capacitance sensing chip features high resolution and extremely low noise, enabling it to detect even minute capacitance changes.
[0046] like Figure 3 As shown, Figure 3This is a circuit diagram of the capacitance acquisition circuit of the capacitance detection chip in this embodiment of the present invention. The parameters of the compensation capacitor and other integrated components of the MS3110 capacitance detection chip can be controlled through registers. The basic measurement principle of the MS3110 capacitance detection chip is as follows: the measured capacitor (the signal under test) and the reference capacitor are charged and discharged simultaneously in opposite timing sequences. The difference between the measured capacitor and the reference capacitor is converted into a voltage output through current integration, low-pass filtering, and amplification. The MS3110 capacitance detection chip contains a 60-bit register and a 100-bit electrically erasable programmable read-only memory (EEPROM). In this embodiment, the EEPROM of the MS3110 capacitance detection chip can be programmed through the I / O port of the MSP430F149 microcontroller, or its register can be programmed directly when the MS3110 is operating in test mode. These settings allow for precise adjustment of the parameters of each module within the MS3110 capacitance detection chip, enabling the MS3110 to adapt to different application scenarios. The initialization of the MS3110 capacitance sensing chip is achieved by initializing the internal registers of the MS3110 capacitance sensing chip through the microcontroller's I / O port, including parameters such as reference capacitance value, adjustable gain, and initial voltage.
[0047] Understandably, a suitable capacitance detection chip can be selected based on specific application requirements. For example, factors such as measurement range, accuracy, cost, and interface type can be considered when selecting a capacitance detection chip.
[0048] like Figure 4 As shown, Figure 4 This is a circuit diagram of the data processing and operation circuit of the MSP430F149 microcontroller in this embodiment of the present invention. The MSP430F149 microcontroller has high integration; its integrated 12-bit A / D converter has a high conversion rate, up to 200kbps, making it applicable to most data acquisition applications and meeting the needs of high-speed data processing. This greatly facilitates microcontroller solutions for testing systems.
[0049] When the MSP430F149 microcontroller operates at a clock frequency of 1MHz, the chip current is approximately 200-400μA. The MSP430F149 also features a standby mode and a power-saving mode. In standby mode, power consumption is only 0.7μA; in power-saving mode, the current can be as low as 0.1μA. Therefore, using the MSP430F149 microcontroller in this test system can further reduce power consumption. Furthermore, other technologies can be employed... Figure 5The pin connectors P1 and P2 shown are used to connect the capacitance detection chip and the microcontroller, enabling the input and output of the voltage signal to be measured between the capacitance detection chip and the microcontroller.
[0050] Furthermore, this capacitive sensor testing system can achieve the following: Figure 6a and Figure 6b The circuit tests shown are designed to meet the increasingly sophisticated testing requirements.
[0051] This capacitive sensor testing system is used to test the capacitive sensor, and the results are as follows: Figure 7 The capacitance test data shown shows that when the test frequency is 100kHz, the capacitance varies depending on the circuit condition, while the loss tangent of the capacitor remains constant.
[0052] This embodiment of the capacitive sensor testing system provides a capacitance detection chip, a microcontroller, and a host computer. The capacitance detection chip converts the acquired capacitance signal into a voltage signal and sends it to the microcontroller. The microcontroller converts the voltage signal into a digital signal, which is then processed by the host computer. This capacitive sensor testing system utilizes a capacitance detection chip with high acquisition frequency and high measurement accuracy, and a microcontroller with high conversion and communication speeds. Therefore, this capacitive sensor testing system can achieve high-speed data acquisition and has high testing accuracy. Furthermore, this capacitive sensor testing system is simple to configure and highly integrated.
[0053] In one embodiment of this utility model, the microcontroller is connected to the capacitance detection chip through an I / O port.
[0054] Specifically, the detection frequency of the capacitance detection chip can be set by controlling its internal registers. In other words, in this embodiment, the microcontroller can connect to the capacitance detection chip through I / O ports and complete the settings of the internal registers of the capacitance detection chip, thereby setting the detection frequency of the capacitance detection chip.
[0055] In one embodiment of this utility model, the microcontroller integrates a serial interface, and the microcontroller is connected to the host computer through the serial interface and a level conversion chip.
[0056] Specifically, different interfaces may have different logic levels. In order to ensure signal compatibility and data transmission security, the microcontroller's serial interface uses a level conversion chip to adjust the signal level to the compatibility range of the target interface. The level conversion chip can be MAX3232. The serial interface integrated by the microcontroller is converted into a three-wire RS232 interface through the MAX3232 chip and then connected to the serial port of the host computer.
[0057] It is understandable that the level conversion chips used include, but are not limited to, MAX3232. Other models of level conversion chips can also meet the requirements by achieving signal compatibility.
[0058] In this embodiment, the serial interface of the microcontroller uses a level conversion chip to ensure the accuracy of data communication and the security of the device, thereby improving the overall compatibility and flexibility of the test system.
[0059] In one embodiment of this utility model, the capacitance detection chip is provided with multiple ports, which are used to connect to a capacitive sensor to obtain the capacitance signal to be measured.
[0060] In one embodiment of this utility model, the microcontroller has a built-in A / D converter, which is used to convert the voltage signal to be measured into a digital signal to be measured.
[0061] Specifically, not all microcontrollers have a built-in A / D converter. In this embodiment, the purpose of the built-in A / D converter is to convert the voltage signal (analog signal) into a digital signal for subsequent data processing and to improve measurement efficiency.
[0062] In one embodiment of this utility model, the A / D converter is a 12-bit A / D converter.
[0063] Specifically, the resolution of the A / D converter is a crucial factor limiting detection accuracy. Higher resolution A / D converters result in more accurate detection. Therefore, when improving the testing system, using an A / D converter with a higher bit depth can be considered. Furthermore, an A / D converter with a suitable bit depth can be selected based on the microcontroller model. For example, the MSP430F149 microcontroller used in this embodiment has a 12-bit A / D converter.
[0064] In one embodiment of this invention, the A / D converter uses either an internal reference voltage or an external reference voltage. Specifically, the reference voltage serves as a stable voltage reference, and the accuracy of the A / D converter is related to the stability of the reference voltage. The higher the stability of the reference voltage, the higher the accuracy of the A / D conversion result. When the A / D converter uses an internal reference voltage, no external components are required, and it can be directly enabled via pins, reducing circuit complexity. When the A / D converter uses an external reference voltage, the external reference voltage generally has higher accuracy, providing a more accurate voltage reference for the A / D converter, thereby improving the accuracy of the AD conversion result. Furthermore, the reference voltage can be changed without modifying the A / D converter itself. The A / D converter can flexibly select the reference voltage according to actual conversion needs, using either an internal or external reference voltage.
[0065] In one embodiment of this invention, the internal reference voltage is 2.5V or 2.25V. Specifically, when the A / D converter uses an internal reference voltage, the reference voltage output of the capacitance detection chip can be used as the reference voltage of the A / D converter. For example, the reference voltage of the capacitance detection chip MS3110 is 2.25V, and in this case, the internal reference voltage of the A / D converter is 2.25V. Alternatively, the internal reference voltage of the A / D converter can also be set to 2.5V.
[0066] See Figure 8 , Figure 8 Another schematic diagram of the capacitive sensor testing system provided in this embodiment of the present invention is shown. The system further includes a power supply module 40, which is connected to the microcontroller 20 and the capacitance detection chip 10, respectively. The power supply module 40 is used to supply power to the microcontroller 20 and the capacitance detection chip 10. Figure 9 As shown, Figure 9 The diagram shown is a power supply module circuit diagram of an embodiment of the present invention. In this embodiment, a voltage regulator chip LM1117-3.3 can be used to output a constant power supply for the microcontroller 20 and the capacitor detection chip 10.
[0067] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0068] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.
Claims
1. A capacitive sensor testing system, characterized in that, The system includes: a capacitance detection chip, a microcontroller, and a host computer; The microcontroller is connected to the capacitance detection chip and the host computer respectively; The capacitance detection chip is used to acquire the capacitance signal to be tested, convert the capacitance signal to be tested into a voltage signal to be tested, and send the voltage signal to be tested to the microcontroller. The microcontroller is used to convert the received voltage signal to be measured into a digital signal to be measured, and to send the digital signal to be measured to the host computer; The host computer is used to process the digital signal to be tested.
2. The capacitive sensor testing system according to claim 1, characterized in that, The microcontroller is connected to the capacitance detection chip via an I / O port.
3. The capacitive sensor testing system according to claim 1, characterized in that, The microcontroller integrates a serial interface, and the microcontroller is connected to the host computer through the serial interface and a level conversion chip.
4. The capacitive sensor testing system according to claim 1, characterized in that, The capacitance detection chip has multiple ports, which are used to connect to a capacitive sensor to obtain the capacitance signal to be measured.
5. The capacitive sensor testing system according to claim 1, characterized in that, The microcontroller has a built-in A / D converter, which is used to convert the voltage signal to be measured into the digital signal to be measured.
6. The capacitive sensor testing system according to claim 5, characterized in that, The A / D converter is a 12-bit A / D converter.
7. The capacitive sensor testing system according to claim 5, characterized in that, The A / D converter uses an internal reference voltage or an external reference voltage.
8. The capacitive sensor testing system according to claim 7, characterized in that, The internal reference voltage is 2.5V or 2.25V.
9. The capacitive sensor testing system according to claim 1, characterized in that, The capacitance detection chip is model MS3110, and the microcontroller is model MSP430F149.
10. The capacitive sensor testing system according to any one of claims 1 to 9, characterized in that, The system further includes a power module, which is connected to the microcontroller and the capacitor detection chip respectively, and is used to supply power to the microcontroller and the capacitor detection chip.