Capacitive key detection device
By designing a capacitive button detection device including a button detection board, a microcontroller, a status indicator device and a capacitor adjustment, the existing detection methods are solved with high cost and poor adaptability, and low-cost and efficient multi-special capacitive button product detection is achieved.
Patent Information
- Application Number
- CN202421844550.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-01
- Publication Date
- 2025-06-13
- Estimated Expiration
- 2034-08-01
AI Technical Summary
The existing capacitive button detection methods require high-cost hardware and computer programs that are not easy to modify, and are difficult to adapt to product detection of different specifications and capacitance differences, increasing production costs.
A capacitive button detection device is designed, including a button detection board, a microcontroller, a status indicator device and a regulating capacitor, which can trigger detection of capacitive button products with multiple specifications and capacitance differences through a simple circuit structure without relying on additional computer equipment.
The device is simple in structure and low in cost. It can be applied on a large scale in the production process, helping manufacturers save production costs while ensuring product quality, and is suitable for product inspection of various types and batches.
Smart Images
Figure CN222979710U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electronic device production and detection, and particularly relates to a capacitive key detection device. Background Art
[0002] A capacitive key is an input device that uses capacitive sensing technology. By touching the touchpad with a finger, the change in capacitance value is sensed to achieve the interaction between the user and the device. The working principle of the capacitive key is to utilize the capacitive induction principle. A conductive film is laid on the touchpad, and an insulating film is laid on the outer layer to form a capacitive structure. When a finger touches the touchpad, a capacitor is formed between the finger and the conductive film. The electrostatic field of the finger affects the value of the capacitor, thereby causing the capacitance value to change. The capacitive key determines the user's operation by detecting the capacitance value.
[0003] Due to the small size, simple structure and certain flexibility of the capacitive key, in practical applications, multiple capacitive keys are often integrated into a strip-shaped or planar integrated structure with an output interface. This capacitive key integrated structure can be easily installed into various products, such as electronic toys and electronic control devices. When producing such capacitive keys, in order to ensure the product quality, each key on it needs to be touched and tested at the time of leaving the factory to ensure that all keys can be successfully triggered. In the existing factory inspection process, the product often needs to be connected to a computer through a connection circuit, and the tester manually touches each key, and then the computer displays the triggering situation of each key.
[0004] This type of detection method requires a high hardware cost and cannot be widely applied on the manual assembly line; in addition, the detection program of the computer is often not easy to modify, and a manufacturer usually produces more than one specification of capacitive keys. Therefore, factors such as different production batches, different production raw materials or different sizes of the capacitive key touch areas will cause the same computer to be inconvenient to adapt to the detection work of all factory products, which further increases the cost invested by the manufacturer in the detection link. Content of the Utility Model
[0005] The purpose of the utility model is to provide a capacitive key detection device, which can perform trigger detection on capacitive key products of various specifications or with capacitance differences without the help of additional computer equipment. Its structure is simple and the cost is low, and it can be purchased and applied on a large scale during the production process, thereby helping the production enterprise to save production costs on the premise of ensuring product quality.
[0006] In order to achieve the above purpose, the specific technical solutions adopted by the utility model are as follows:
[0007] A capacitive key detection device includes a capacitive key product. The capacitive key product includes multiple sub - keys and a signal communication port electrically connected to all the sub - keys. It is characterized in that the device further includes a key detection board. On the key detection board, there is a serial port socket for connecting the signal communication port, a micro - controller electrically connected to the serial port socket, and a status indication device electrically connected to the output pins of the micro - controller and used to display the trigger status of each sub - key. An adjustment capacitor is also arranged on the key detection board. One end of the adjustment capacitor is grounded, and the other end is connected to the CAP capacitance pin of the micro - controller.
[0008] Thus, the capacitive key product is the product to be detected, which consists of multiple sub - keys and a signal communication port electrically connected to all the sub - keys. The signal communication port is an integrated pin header interface that connects all the sub - keys. Whenever an object such as a finger touches the touch area of a sub - key, the pin corresponding to this sub - key can output a trigger signal.
[0009] The key detection board is specifically a PCB circuit board. There is a serial port socket on it that cooperates with the signal communication port. Inserting the signal communication port into the serial port socket can complete the connection. There is a micro - controller on the key detection board, and the micro - controller is electrically connected to the serial port socket. Specifically, different wire paths of the serial port socket are respectively connected to the input pins of the micro - controller. When a sub - key is touched, the trigger signal is sequentially input to the designated input pins of the micro - controller through the signal communication port and the serial port socket.
[0010] The key detection board is also provided with a status indication device electrically connected to the output pins of the micro - controller and used to display the trigger status of each sub - key. The status indication device includes multiple indication units, and each indication unit corresponds to a sub - key to reflect its trigger status. So whenever a sub - key is touched, there is an indication unit corresponding to it that performs an indication action. This indication action can be optical indication or acoustic indication, such as various LED lights or buzzers in the prior art.
[0011] An adjustment capacitor is also arranged on the key detection board. One end of it is grounded, and the other end is connected to the CAP capacitance pin of the micro - controller. By adjusting its capacitance value, the sensitivity of the micro - controller to the trigger signals of each sub - key in the capacitive key product can be changed. Since a manufacturer often produces more than one specification of capacitive keys, there are problems such as different production batches, differences in production raw materials, or different sizes of the touch areas of capacitive keys. These problems will cause different intensities of trigger signals generated by different capacitive key products. Through the adjustment of the above - mentioned adjustment capacitor, this product can meet the detection work of all types of capacitive key products. Specifically, the adjustment capacitor can be realized in the form of an adjustable - capacitance capacitor in the prior art or directly replacing capacitors with different capacitance values.
[0012] In summary, this capacitive key detection device mainly completes the detection work of different products in the form of a simple circuit structure integrated on a PCB board. Its structure is simple and the cost is low. Therefore, in the factory quality inspection link, each quality inspector can have one, which greatly improves the production efficiency of the entire production end. In addition, the capacitive key detection device is also provided with an adjustable tuning capacitor. By adjusting it, a set of this device can be applied to the detection work of products of multiple types and multiple production batches, further saving costs and improving production efficiency.
[0013] As a preference of the present utility model, this capacitive key detection device further includes a power supply device disposed on the key detection board. The power supply device includes a DC power socket for connecting to a power source and a low-dropout linear regulator with one end connected to the DC power socket and the other end connected to the VDD pin of the microcontroller.
[0014] Thus, the power supply module is used to provide a power supply connection function for this device. It includes a DC power socket, which can be selected as a DC power socket such as DC. DC has the ability to connect to an internal battery or an external DC power source. Its pin and pin are grounded, and its pin is connected to the VIN pin of the low-dropout linear regulator. The low-dropout linear regulator is also used to provide a stable DC voltage power supply. It can work under a smaller output-input voltage difference. Ground its NC pin, and the VOUT pin can output the working voltage required by the microcontroller.
[0015] As a preference of the present utility model, the status indication device includes a plurality of independent LED lamp beads, and each LED lamp bead is electrically connected to an output pin of the microcontroller.
[0016] The status indication device includes a plurality of independent LED lamp beads, and each LED lamp bead is electrically connected to an output pin of the microcontroller. When the microcontroller receives a trigger level signal from an input pin, it will correspondingly output a level signal to the designated connected LED lamp bead, and the lamp bead will automatically light up to display the trigger status of this sub-key in the form of an optical signal.
[0017] As a preference of the present utility model, a feedback current-limiting resistor is serially disposed between each LED lamp bead and the output pin of the microcontroller.
[0018] Thus, because the lighting voltage and current of the LED lamp bead are very small, a feedback current-limiting resistor is serially disposed between each LED lamp bead and the output pin of the microcontroller, which can not only protect the LED lamp bead so that it can be normally triggered, but also protect the microcontroller from being burned out by abnormal current.
[0019] Preferably, between the microcontroller and the serial port socket, a plurality of pre - current - limiting resistors for protecting the microcontroller are connected in series.
[0020] Therefore, since a manufacturer often produces more than one specification of capacitive buttons, there are problems such as different production batches, differences in production raw materials, or different sizes of the touch areas of capacitive buttons. This problem will cause different intensities of trigger signals generated by different capacitive button products. In order to prevent some strong trigger signal currents from directly transmitting to the microcontroller when the capacitance adjustment is not in place, a plurality of pre - current - limiting resistors are connected in series between the microcontroller and the serial port socket.
[0021] Preferably, a filter capacitor C is connected between the VDD pin and the VSS pin of the microcontroller.
[0022] The VDD pin of the microcontroller is connected to the voltage output terminal of the low - dropout linear regulator, and the VSS pin is grounded. At the same time, a filter capacitor C is connected in parallel between the VDD pin and the VSS pin of the microcontroller. The filter capacitor C can act as a bypass capacitor, enabling high - frequency interference signals to directly reach the ground wire through it, thereby reducing the noise on the power line and effectively improving the performance and stability of the circuit.
[0023] Preferably, the pre - current - limiting resistors and the feedback current - limiting resistors are surface - mount resistors in 0603 package form.
[0024] Considering that this device is mainly applied to manual operation and should have a smaller volume to increase usability, surface - mount resistors in 0603 package form are used as the pre - current - limiting resistors and the feedback current - limiting resistors, thereby reducing the space required for device installation in this device and reducing the overall volume.
[0025] Preferably, the adjustment capacitor is a surface - mount capacitor with continuously adjustable capacitance value.
[0026] Therefore, by selecting a surface - mount capacitor with a small volume and high precision and continuously adjustable capacitance as the adjustment capacitor, the original adjustment function can be satisfied on the premise of reducing the overall volume of this device.
[0027] In summary, the present utility model has the following beneficial effects:
[0028] This capacitive key detection device mainly completes the detection work of different products in the form of being integrated on the PCB board with a simple circuit structure. It has a simple structure and low cost, so each quality inspection personnel can have one during the factory quality inspection process, greatly improving the production efficiency of the entire production end. In addition, the capacitive key detection device is also provided with an adjustable capacitance, and by adjusting it, a set of this device can be applied to the detection work of multiple types and multiple production batches of products, further saving costs and improving production efficiency. Brief Description of the Drawings
[0029] Figure 1 is a schematic structural diagram of this capacitive key detection device;
[0030] Figure 2 is a schematic diagram of this capacitive key product;
[0031] Figure 3 is the circuit connection schematic diagram of each component on the key detection board;
[0032] Figure 4 is the circuit schematic diagram of the serial port socket;
[0033] Figure 5 is the circuit schematic diagram of the power supply device.
[0034] In the figure: capacitive key product 1, sub-key 11, signal communication port 12, key detection board 2, serial port socket 3, microcontroller 4, status indication device 5, adjustable capacitance 6, power supply device 7, DC power socket 71, low dropout linear regulator 72. Detailed Description of the Preferred Embodiment
[0035] The following further describes the present invention in detail with reference to the accompanying drawings.
[0036] This specific embodiment is only an interpretation of the present invention, and it is not a limitation of the present invention. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of the present invention, it is protected by the patent law.
[0037] As Figure 1 、 Figure 2 and Figure 3 shown, the capacitive key product 1 is the product to be detected, which is composed of a plurality of sub-keys 11 and a signal communication port 12 electrically connected to all the sub-keys 11. The signal communication port 12 is an integrated pin header interface, which connects all the sub-keys 11. Whenever an object such as a finger touches the touch area of the sub-key 11, the pin corresponding to the sub-key 11 can output a trigger signal.
[0038] As Figure 1, Figure 3 and Figure 4 As shown in Figure 3 and Figure 4 , the button detection board 2 is specifically a PCB circuit board, on which there is a serial port socket 3 cooperatively connected with the signal communication port 12. Inserting the signal communication port 12 into the serial port socket 3 can complete the connection. A microcontroller 4 is arranged on the button detection board 2, and the microcontroller 4 is electrically connected to the serial port socket 3. Specifically, different wire paths of the serial port socket 3 are respectively connected to the input pins of the microcontroller 4. When the sub-button 11 is touched, the trigger signal is sequentially input to the specified input pin of the microcontroller 4 through the signal communication port 12 and the serial port socket 3. In this embodiment, a total of 12 touch buttons, namely KEY1 to KEY11, are first connected to 12 pre-stage current-limiting resistors R1 to R11 (1 kΩ) and then connected to the TP1 to TP11 input pins of the microcontroller 4.
[0039] The button detection board 2 is also provided with a status indicating device 5 electrically connected to the output pins of the microcontroller 4 and used to display the trigger status of each sub-button 11. In this embodiment, the status indicating device 5 includes a plurality of independent LED beads D1 to D11, and each LED bead is electrically connected to an output pin (D1 to D11) of the microcontroller 4. A feedback current-limiting resistor, that is, R12 to R22 (600 Ω), is serially arranged between each LED bead and the output pin of the microcontroller 4.
[0040] After the microcontroller 4 receives a trigger level signal from the input pin, it will correspondingly output a level signal to the specified connected LED bead, and the bead will automatically light up to display the trigger status of the sub-button 11 in the form of an optical signal.
[0041] The button detection board 2 is also provided with an adjustment capacitor 6 (i.e., capacitor C2, and the capacitance value is adjusted to 3.3 nF here). One end of it is grounded, and the other end is connected to the CAP capacitance pin of the microcontroller 4. By adjusting its capacitance value, the sensitivity of the microcontroller 4 to the trigger signals of each sub-button 11 in the capacitive button product 1 can be changed. By adjusting the above adjustment capacitor 6, this product can meet the detection work of all types of capacitive button products 1.
[0042] As Figure 5As shown, the capacitive key detection device further includes a power supply device 7 disposed on the key detection board 2. The power supply device 7 includes a DC power socket 71 (i.e., CN2 of type DC005) for connecting to a power supply, and a low dropout linear regulator 72 (i.e., T1) with one end connected to the DC power socket 71 and the other end connected to the VDD pin of the microcontroller 4. A filter capacitor C4 is connected in parallel between the VIN pin and the ground terminal of the low dropout linear regulator T1, and a filter capacitor C5 is connected in parallel between the VOUT pin and the ground terminal. The operating voltage VDD3 output from the VOUT pin of the low dropout linear regulator T1 powers the microcontroller 4. A filter capacitor C1 is connected between the VDD pin and the VSS pin of the microcontroller 4 to reduce the noise on the power line and improve the performance and stability of the circuit.
[0043] Considering that this device is mainly applied to manual operation and should have a smaller volume to increase usability, surface mount resistors in 0603 package form are used as the front-end current limiting resistor and the feedback current limiting resistor, thereby reducing the space required for device installation of this device and reducing the overall volume. Surface mount capacitors that are small in volume and have high precision and are continuously adjustable are selected as the adjustment capacitor 6, which can meet the original adjustment function on the premise of reducing the overall volume of this device.
[0044] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A capacitive key detection device, comprising a capacitive key product (1), wherein the capacitive key product (1) comprises a plurality of sub-keys (11) and a signal communication port (12) electrically connected to all the sub-keys (11), characterized in that: The capacitive key detection device further comprises a key detection board (2); the key detection board (2) is provided with a serial port socket (3) for connecting to the signal communication port (12), a microcontroller (4) electrically connected to the serial port socket (3), and a state indicating device (5) electrically connected to an output pin of the microcontroller (4) and used to display the triggering state of each sub-key (11); the key detection board (2) is also provided with an adjusting capacitor (6), one end of the adjusting capacitor (6) is grounded, and the other end is connected to the CAP capacitor pin of the microcontroller (4).
2. A capacitive button detection device according to claim 1, characterized in that: The state indicating device (5) comprises a plurality of independent LED lamp beads, each of which is electrically connected to an output pin of the microcontroller (4).
3. A capacitive button detection device according to claim 2, characterized in that: A feedback current limiting resistor is arranged in series between each LED lamp bead and the output pin of the microcontroller (4).
4. A capacitive button detection device according to claim 3, characterized in that: A plurality of pre-current limiting resistors for protecting the microcontroller (4) are arranged in series between the microcontroller (4) and the serial port socket (3).
5. A capacitive button detection device according to claim 4, characterized in that: The capacitive key detection device further comprises a power supply device (7) arranged on the key detection board (2), the power supply device (7) comprising a DC power socket (71) for connecting to a power source and a low voltage difference linear regulator (72) having one end connected to the DC power socket (71) and the other end connected to a VDD pin of the microcontroller (4).
6. A capacitive button detection device according to claim 5, characterized in that: A filter capacitor C1 is connected between the VDD pin and the VSS pin of the microcontroller (4).
7. A capacitive button detection device according to claim 4, characterized in that: The pre-current limiting resistor and the feedback current limiting resistor are chip resistors in 0603 package form.
8. A capacitive button detection device according to any one of claims 1 to 7, characterized in that: The regulating capacitor (6) is a chip capacitor with a continuously adjustable capacitance value.