Custom key control device for automobile steering wheel and universal steering wheel

Abstract

A user-defined key control device for an automobile steering wheel and a universal steering wheel, the device comprises a plurality of keys mounted on the steering wheel, a main control module used for receiving input signals of the keys and converting the key input into corresponding control output signals according to a preset mapping relation, and a control module electrically connected with the main control module and used for controlling the input signals of the keys. The communication interface module is used for sending the control output signal to a vehicle-mounted system through a vehicle bus and is used for establishing communication connection between the main control module and an external mobile terminal; and the wireless communication module, the power management module and the OBD data acquisition module are used for enabling a user to carry out customized configuration or remote updating on the function of each key through the mobile terminal. The embodiment of the utility model solves the problems that the traditional steering wheel key is fixed in function and poor in expansibility; the system has the advantages of supporting a user-defined key function, being compatible with various vehicle-mounted bus protocols, realizing remote configuration updating and providing stable multi-stage power supply.

Description

Technical Field

[0001] This utility model relates to the field of control circuit technology, specifically to a custom button control device for a car steering wheel. Background Technology

[0002] Currently, most vehicles use steering wheel buttons with fixed functions, meaning each button has its own pre-set control logic at the factory, such as volume adjustment, answering calls, and cruise control, which users cannot change or expand. While this traditional solution can achieve basic operation control, its functions are highly coupled with the vehicle's system, lacking flexibility and making it difficult to adapt to increasingly diverse in-vehicle application scenarios. It is also not conducive to personalized customization or integration with aftermarket systems.

[0003] However, most existing steering wheel button structures are fixed circuit schemes, and the control functions are limited by the original factory configuration. They do not have the ability to be customized by users. Once users replace the in-vehicle central control, expand the in-vehicle functions, or want to remap the original functions, they need to change the hardware wiring or reprogram the ECU, which has problems such as cumbersome operation, high system coupling, and high maintenance costs.

[0004] In addition, existing steering wheel button systems often lack modular design, are incompatible with multiple communication protocols, and lack the ability to link with mobile terminals, making remote configuration and OTA operation impossible. Users urgently need a steering wheel button control device with modular communication, customizable function configuration, remote management, and low-power power supply capabilities to improve system scalability, adaptability, and user personalization experience. Utility Model Content

[0005] The purpose of this application is to provide a custom button control device for automotive steering wheels and a universal steering wheel, which has the advantages of supporting user-defined button functions, being compatible with multiple vehicle bus protocols, enabling remote configuration updates, and providing stable multi-level power supply.

[0006] On the one hand, this application provides a custom button control device for an automobile steering wheel, the technical solution of which is as follows:

[0007] Including multiple buttons mounted on the steering wheel, and also:

[0008] The main control module is used to receive input signals from multiple buttons and convert the button inputs into corresponding control output signals according to a preset mapping relationship.

[0009] The communication interface module is electrically connected to the main control module and is used to send the control output signal to the vehicle system through the vehicle bus;

[0010] The wireless communication module is used to establish a communication connection between the main control module and an external mobile terminal, so that the user can customize the function of each button or update it remotely through the mobile terminal.

[0011] The power management module is used to receive the vehicle power supply and provide a stable operating voltage for the main control module, communication interface module and wireless communication module;

[0012] The OBD data acquisition module is used to acquire vehicle power information or vehicle speed information.

[0013] On the other hand, this application also proposes a universal steering wheel, including the aforementioned custom button control device for automobile steering wheels.

[0014] As can be seen from the above, the custom button control device and universal steering wheel provided in this application include multiple buttons installed on the steering wheel, a main control module, a communication interface module, a wireless communication module, and a power management module. The wireless communication module enables remote custom configuration of button functions, the communication interface module is compatible with CAN and LIN bus protocols, and the power management module provides multi-level regulated power supply. This solves the problems of fixed functions and poor expandability of traditional steering wheel buttons, and has the advantages of supporting user-defined button functions, compatibility with multiple vehicle bus protocols, remote configuration updates, and providing stable multi-level power supply. Attached Figure Description

[0015] 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 these drawings without creative effort.

[0016] Figure 1 This is a circuit block diagram of an embodiment of the present utility model;

[0017] Figure 2 This is a circuit diagram of the Bluetooth communication unit of this utility model;

[0018] Figure 3 This is a circuit diagram of the CAN communication circuit of this utility model;

[0019] Figure 4 This is the circuit diagram of the LIN communication unit of this utility model;

[0020] Figure 5 This is a circuit diagram of the 2.4GHz radio frequency communication unit of this utility model;

[0021] Figure 6This is a circuit diagram showing the signal connection of this utility model;

[0022] Figure 7 This is a circuit diagram of the low-dropout linear voltage regulator circuit of this utility model;

[0023] Figure 8 This is the circuit diagram of the step-down voltage regulator circuit of this utility model;

[0024] Figure 9 This is the circuit diagram of the multi-stage voltage regulated power supply circuit of this utility model;

[0025] Figure 10 This is the circuit diagram of the main control module of this utility model;

[0026] Figure 11 This is the circuit diagram of the first part of the indicator light unit of this utility model;

[0027] Figure 12 This is the second part of the circuit diagram of the indicator light unit of this utility model;

[0028] Figure 13 This is the circuit diagram of the third part of the indicator light unit of this utility model.

[0029] Figure label:

[0030] 100. OBD data acquisition module; 200. Main control module; 300. Communication interface module; 310. CAN communication circuit; 320. LIN communication circuit; 400. Wireless communication module; 500. Power management module. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings.

[0032] This specific embodiment is merely an explanation of the present utility model and is not intended to limit the present utility model. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive element, but as long as they are within the scope of the claims of the present utility model, they are protected by patent law.

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0035] In existing technologies, automotive steering wheel buttons mostly employ a fixed-function design, with factory-preset control logic that cannot be altered, preventing users from adjusting button functions according to their needs. As in-vehicle systems become increasingly feature-rich, traditional solutions struggle to adapt to diverse application scenarios, lacking flexibility. Furthermore, existing solutions typically rely on a single communication protocol, making them incompatible with different in-vehicle systems and unsupporting remote configuration. Users must disassemble hardware or modify software to update functions, resulting in complex operations and high maintenance costs.

[0036] To address the aforementioned issues, the applicant conducted an in-depth analysis of the fixed functions and limited protocols of traditional steering wheel button systems. First, it was observed that the rapid iteration of in-vehicle electronic systems led to increased user demand for expanded button functionality, while hardware-level modifications posed operational risks and compatibility problems. Subsequently, the trend of interaction between mobile terminals and in-vehicle devices was identified, proposing the possibility of remote configuration using wireless communication. After reviewing vehicle bus communication protocols, a main control architecture adaptable to multiple protocols was designed, ultimately forming a modular design scheme. Software-defined button functions replace hardware circuit reconstruction, reducing system coupling.

[0037] Therefore, refer to Figure 1 This application proposes a control device consisting of multiple buttons mounted on a steering wheel;

[0038] The main control module 200 is used to receive input signals from multiple buttons and convert the button inputs into corresponding control output signals according to a preset mapping relationship.

[0039] The communication interface module 300 is electrically connected to the main control module 200 and is used to send the control output signal to the vehicle system through the vehicle bus;

[0040] The wireless communication module 400 is used to establish a communication connection between the main control module 200 and an external mobile terminal, so that the user can customize the function of each button or update it remotely through the mobile terminal.

[0041] The power management module is used to receive the vehicle power supply and provide a stable operating voltage for the main control module 200, the communication interface module 300 and the wireless communication module 400;

[0042] The OBD data acquisition module 100 is used to acquire vehicle power information or vehicle speed information.

[0043] The main control module 200 is a control unit with signal processing and protocol conversion functions, which can be implemented using a microcontroller or programmable logic device. It is responsible for converting the trigger signals from physical buttons into control commands recognizable by the vehicle system. The communication interface module 300 is the hardware circuit that implements vehicle bus protocol conversion. It can be implemented using a composite circuit including CAN and LIN communication chips to ensure compatibility with different vehicle systems. The wireless communication module 400 is a communication component that supports wireless connection to mobile devices. It can be implemented using a Bluetooth and WiFi dual-mode chip, facilitating function configuration by users through mobile applications. The power management module is a multi-stage regulated power supply system, which can be implemented using a combination circuit of linear regulators and switching power supplies to provide suitable operating voltages for each functional module.

[0044] Specifically, when a user presses a steering wheel button, the main control module 200 collects the button trigger signal in real time and generates a corresponding control command based on the mapping relationship stored in non-volatile memory. This command is converted into a data frame conforming to the vehicle bus protocol, such as a CAN bus message or a LIN bus signal, by the communication interface module 300 and transmitted to the in-vehicle entertainment system or driver assistance module. After the user connects to the wireless communication module 400 through a mobile terminal application, they can redefine the control functions corresponding to each button, and the new configuration data is written to the storage unit of the main control module 200 via a wireless link. The power management module, through a multi-stage voltage regulation design, converts the vehicle's 12V power supply to 3.3V and 5V DC power, ensuring stable operation of the main control chip and communication module under different operating conditions.

[0045] Compared to existing technologies, traditional solutions require hardware rewiring to adjust functionality, while this solution redefines button functions through software configuration, significantly reducing operational complexity. Existing technologies typically support only a single communication protocol, while this solution's communication interface module 300 integrates multiple bus protocol processing capabilities, adapting to the electronic architectures of different vehicle models. Furthermore, existing button systems lack wireless interaction capabilities; this solution introduces a wireless communication module 400, allowing users to update functions without physically touching the device, improving ease of use.

[0046] Through the above technical solution, this application effectively solves the problems of fixed steering wheel button functions and protocol compatibility, achieving flexible configuration of button functions and cross-platform compatibility. Users can adjust button functions at any time according to vehicle system upgrades or personalized needs, without relying on professional equipment or disassembling steering wheel components. Multi-protocol communication interfaces ensure the device can be widely used in different brand vehicle models, while a stable power management design guarantees reliable operation in complex electromagnetic environments, significantly improving user experience and system scalability.

[0047] Furthermore, the communication interface module 300 includes a CAN communication circuit 310 and a LIN communication circuit 320.

[0048] Among them, the CAN communication circuit 310 refers to a communication circuit based on the controller area network. Specifically, it can be implemented using a circuit structure including a CAN communication chip, a filter capacitor, and a terminating resistor, and is used to achieve high-speed data transmission and anti-interference communication between electronic control units within the vehicle. The LIN communication circuit 320 refers to a communication circuit based on the local interconnection network. Specifically, it can be implemented using a circuit structure including a LIN communication chip, a pull-up resistor, and a filter capacitor, and is used to achieve low-cost communication and signal stability control between low-speed auxiliary devices within the vehicle.

[0049] Specifically, the CAN communication circuit 310 and the LIN communication circuit 320 are integrated within the communication interface module 300. The main control module 200 selects the corresponding communication circuit for signal transmission based on the protocol type of the vehicle system. When the vehicle bus is in a high-speed communication scenario, the CAN communication chip suppresses signal reflection and high-frequency noise through a terminating resistor and a common-mode filter capacitor to ensure the integrity of data transmission. When the vehicle bus is in a low-speed control scenario, the LIN communication chip maintains a stable signal level through a pull-up resistor and a bus filter capacitor to avoid pulse interference. The two communication circuits are connected to the main control module 200 through independent pins. The main control module 200 automatically switches the communication mode according to a preset protocol, achieving compatibility with the communication needs of different vehicle models without the need for an external switching circuit.

[0050] Reference Figure 3 Specifically, the CAN communication circuit includes a CAN communication chip U6, capacitors C11, C12, and C13, and a resistor R11, wherein:

[0051] The power supply pin of the CAN communication chip U6 is connected to the stable voltage provided by the power management module, and the ground pin is connected to the system ground line to provide the operating voltage for the chip.

[0052] The capacitor C11 is connected between the ground pin of the chip and ground, and is used to perform high-frequency decoupling filtering on the communication chip;

[0053] The capacitors C12 and C13 are connected between pin CANH and ground, and pin CANL and ground, respectively, to suppress common-mode interference and filter high-frequency noise at both ends of the CAN bus.

[0054] The resistor R11 is connected between pin CANH and pin CANL and is used as a bus termination matching resistor to improve signal integrity and prevent signal reflection.

[0055] The TXD and RXD pins of the CAN communication chip U6 are connected to the communication port of the main control module, respectively, to realize the data transmission and reception functions of the CAN protocol.

[0056] High-frequency decoupling filtering refers to filtering out high-frequency interference signals using capacitors. Specifically, this can be achieved by connecting a surface-mount ceramic capacitor in parallel between the chip's power supply pin and ground, eliminating high-frequency noise on the communication chip's power lines. Common-mode interference suppression refers to suppressing common-mode noise in the CAN bus signal. This can be achieved by connecting a Y-type capacitor across the bus pin and ground, reducing the impact of external electromagnetic interference on the differential signal. Bus termination matching resistors are impedance matching components connected at both ends of the CAN bus. Specifically, a 120Ω precision resistor can be used to absorb signal reflections and maintain bus impedance continuity. Data transmission and reception functions refer to the bidirectional communication capability between the CAN communication chip and the main control module 200. Specifically, commands from the main control module 200 can be sent via the TXD pin, and data packets can be received on the bus via the RXD pin.

[0057] Specifically, the CAN communication chip U6 receives a regulated 5V voltage through its power supply pin and achieves equipotential connection with the vehicle system ground through its ground pin. Capacitor C11 forms a high-frequency noise filtering loop between the chip's power supply pin and ground, filtering out switching noise on the power line. Capacitors C12 and C13 are connected across CANH and ground, and CANL and ground, respectively, forming a common-mode filtering network to suppress the influence of external electromagnetic interference on the differential signal lines. Resistor R11, as a bus termination matching resistor, is connected between CANH and CANL, eliminating signal reflection and ensuring bus impedance matching. The main control module 200 sends control commands to the CAN communication chip through the TXD pin and simultaneously receives data feedback from the vehicle bus through the RXD pin, realizing bidirectional communication.

[0058] Reference Figure 4 Furthermore, the LIN communication circuit includes multiple LIN communication units with identical structures. Each LIN communication unit includes a LIN communication chip U4, resistor R2, resistor R3, diode D2, and capacitor C6, wherein:

[0059] The transmit and receive pins of the LIN communication chip are connected to the serial communication port of the main control module, respectively, to realize the message reception and response function of the LIN bus.

[0060] The VBAT pin of the LIN communication chip is connected to the vehicle's 12V power supply via connector J1 and connected in series via diode D2.

[0061] The resistor R2 is connected between the VBAT pin of the LIN communication chip and the LIN bus to maintain a stable high-level state of the LIN bus.

[0062] The resistor R3 is a pull-up resistor for the main control module's communication pin, used to improve the stability of the RX pin signal;

[0063] The capacitor C6 is connected in parallel between the LIN bus and ground to suppress spike pulses and interference signals on the LIN line.

[0064] The ground pin of the LIN communication chip is connected to system ground.

[0065] The LIN communication chip refers to the integrated circuit used to implement the LIN bus communication protocol conversion. Specifically, it can be implemented using the TJA1020 series chip, converting the serial communication signals of the main control module 200 into differential signals conforming to the LIN protocol. Diode D2 is a unidirectional conducting element, such as a 1N4007 diode, but not limited to this. It is used to prevent damage to the chip caused by reverse power connection or voltage backflow. Resistor R2 is a current-limiting element, specifically a 1kΩ surface-mount resistor, used to maintain a stable high level in the LIN bus idle state, preventing bus level drift. Resistor R3 is a pull-up resistor, specifically a 4.7kΩ surface-mount resistor, used to improve the anti-interference capability of the main control module 200's receiving pin. Capacitor C6 is a filtering element, specifically a 100nF ceramic capacitor, used to absorb high-frequency noise and transient pulse interference on the LIN bus.

[0066] Specifically, the LIN communication unit is connected to the vehicle's 12V power supply system via connector J1, with diode D2 providing polarity protection for the input power. The transmit and receive pins of the LIN communication chip are directly connected to the serial communication port of the main control module 200, enabling LIN message transmission and reception. Resistor R2 is connected between the VBAT pin and the LIN bus to ensure the bus maintains a preset high level when there is no communication, preventing false signal triggering. Resistor R3 is connected to the receive pin of the main control module 200, enhancing signal stability during long-distance transmission through a pull-up effect. Capacitor C6 is connected in parallel between the LIN bus and ground to filter out common-mode noise generated by the vehicle's electromagnetic environment. Multiple LIN communication units operate independently, forming redundant communication paths and supporting LIN bus branch connections with different vehicle-mounted devices.

[0067] Reference Figure 2 and Figure 5 Furthermore, the wireless communication module 400 includes a Bluetooth communication unit and a 2.4GHz radio frequency communication unit. The Bluetooth communication unit is used to establish a communication connection with the mobile terminal and realize display mode setting, operation status query and parameter configuration through the application pre-installed on the mobile terminal; the radio frequency communication unit is used to realize data exchange between the main control module 200 and the OBD data acquisition module 100.

[0068] The Bluetooth communication unit refers to a low-power wireless communication unit that supports the Bluetooth protocol. Specifically, it can be implemented using an HC-05 Bluetooth module. This module supports AT command sets for pairing and data transmission, establishing a wireless connection channel between the mobile terminal and the control device. The radio frequency communication unit refers to a wireless transceiver circuit operating in the 2.4GHz frequency band. Specifically, it can be implemented using an NRF24L01 chip. This chip supports bidirectional data transmission and multi-channel frequency hopping technology, enabling high-speed data interaction with the vehicle's OBD interface module.

[0069] Specifically, after the Bluetooth communication unit pairs with the mobile terminal via the HFP protocol, the user can select the button function mapping relationship in the mobile terminal application and send the configuration command to the main control module 200 to complete the function update. The radio frequency communication unit connects to the main control module 200 via the SPI interface, receives vehicle status information sent by the OBD data acquisition module 100 in real time, such as engine speed, vehicle speed, or fault codes, and feeds the data back to the main control module 200 to trigger preset button linkage functions. The Bluetooth unit and the radio frequency unit adopt a time-division multiplexing mechanism, and the main control module 200 schedules communication resources according to operation priority to avoid signal conflicts.

[0070] Compared to existing technologies, traditional steering wheel button systems only support a single communication method and are incompatible with external devices, such as connecting to the vehicle's system only through hardwiring. This solution integrates Bluetooth and radio frequency dual-mode communication, enabling remote configuration of button functions via mobile terminals and establishing a real-time data channel with the vehicle's diagnostic system. This allows button functions to be dynamically adjusted according to the vehicle's status. For example, when a vehicle malfunction is detected, the radio frequency unit can retrieve the fault code and trigger the corresponding button's warning light to flash.

[0071] Reference Figure 6 The custom button control device for the automotive steering wheel further includes a set of external interfaces and signal protection circuits for outputting and inputting vehicle communication signals, LED module power supplies, and button signals. Specifically, the interface module includes several pin header connectors (e.g., J2, J3, J4) for connecting to the CAN bus, LIN bus, LED power supply output, and button signal input, respectively.

[0072] Specifically, the CAN and LIN bus interfaces output communication signals such as CANH, CANL, LIN1, and LIN2 through corresponding pins of the connector, and are grounded to the system via a ground wire. To ensure interface signal stability and prevent voltage reverse flow, two parallel Schottky diodes, D5 and D6, are installed in the interface signal output path, wherein:

[0073] Diode D5 is connected in series between the LED power output and the signal line to limit the impact of reverse current on the main control or external load, improving power supply safety. Diode D6 is connected between the button signal line and the system I / O terminal to suppress input signal spikes or accidental voltage, preventing damage to the main control port. Both diodes D5 and D6 are fast recovery devices (e.g., SS14 diodes, but not limited to) to meet the response speed requirements under dynamic changes in steering wheel signals.

[0074] This embodiment can effectively improve the communication compatibility and system security of the device in complex vehicle electrical environments, and realize stable connection and expanded support for custom button functions and LED display functions.

[0075] Reference Figure 7 Furthermore, the power management module 500 includes a low-dropout linear regulator circuit for powering the wireless Bluetooth communication module. The low-dropout linear regulator circuit includes a voltage conversion chip U5, a resistor R27, and capacitors C14, C15, C16, and C17. The first terminal of the voltage conversion chip U5 is connected to a 5V power supply, one end of the resistor R27, and one end of the capacitor C16. The other end of the resistor R27 is connected to the second terminal of the voltage conversion chip U5. The other end of the capacitor C16 is connected to the third terminal of the voltage conversion chip U5, one end of the capacitor C14, one end of the capacitor C15, one end of the capacitor C17, and a ground terminal. The other ends of the capacitors C14, C15, and C17 are connected to the sixth terminal of the voltage conversion chip U5 and the power supply terminal.

[0076] Among them, the low-dropout linear regulator circuit refers to a linear regulator circuit with a small voltage drop between the input and output. It can be implemented using a chip with low quiescent current characteristics and is suitable for the wireless communication module 400, which is sensitive to power supply efficiency. The voltage conversion chip U5 refers to an integrated circuit that converts the input voltage into a stable output voltage. For example, it can use an LDO chip such as TPS796, but is not limited to this. It is used to achieve voltage conversion and suppress input voltage fluctuations, but is not limited to this. Resistor R27 refers to an external voltage divider resistor used to adjust the output voltage. For example, a 10kΩ surface-mount resistor can be used, and the feedback voltage division ratio can be adjusted by changing the resistance value. Capacitors C14, C15, C16, and C17 refer to energy storage components used for filtering. For example, a combination of ceramic capacitors and electrolytic capacitors can be used to suppress high-frequency noise and low-frequency ripple in the input power supply, respectively.

[0077] Specifically, after receiving the 5V input voltage from the vehicle's power supply, the voltage conversion chip U5 outputs the target voltage through its internal adjustment circuit. Resistor R27, in conjunction with the chip's internal reference voltage, forms a feedback network to maintain a stable output voltage. Capacitor C16 is connected in parallel between the input terminal and ground to absorb transient interference at the input terminal; capacitors C14 and C15 are connected in series between the output terminal and ground to filter out high-frequency noise in the output voltage; capacitor C17 is connected across the input and output terminals to further suppress power coupling interference. The capacitance values ​​of each capacitor can be selected according to actual needs; for example, C16 can be a 10μF electrolytic capacitor, and C14 and C15 can be 0.1μF ceramic capacitors. This multi-stage filtering structure ensures that the wireless Bluetooth communication module receives a stable power supply in the complex electromagnetic environment of the vehicle.

[0078] Reference Figure 8 Furthermore, the power management module 500 includes a buck regulator circuit for supplying power to the OBD data acquisition module 100. The buck regulator circuit includes a buck converter chip U3, resistors R22, R23, R24, and R25, an inductor L1, capacitors C1, C6, C7, C8, and C9, a diode D4, and a transient voltage suppressor D5, wherein:

[0079] One end of resistor R22 is connected to the input power supply VIN, and the other end is connected to the positive terminal of diode D4. The negative terminal of diode D4 is connected to one end of transient voltage suppressor D5, the input terminal of buck converter chip U3, one end of resistor R23, and one end of capacitors C9 and C7. The other ends of transient voltage suppressor D5, capacitors C9 and C7 are all connected to ground. The other end of resistor R23 is connected to the enable terminal of buck converter chip U3. Pin 2 of buck converter chip U3 is connected to ground, and pin 6 of buck converter chip U3 is connected to the boost pin. Through capacitor C6, it is connected to an inductor L1 in parallel with resistor R24. The other end of inductor L1 is connected to the output terminal. Pin 1 of buck converter chip U3 is connected to the node between resistor R25 and resistor R24 ​​for feedback control. The output terminal of buck converter chip U3 is connected to output capacitors C1 and C8, and outputs a stable 5V voltage for use by OBD data acquisition module 100.

[0080] Among them, the step-down converter chip refers to an integrated circuit that converts the input voltage to the output voltage by adjusting the duty cycle of the switch. Specifically, it can be implemented using a chip such as MP2451, but it is not limited to this. It has a built-in power switch and PWM controller, which can step down the 12V or 24V input of the vehicle battery to 5V.

[0081] A transient voltage suppressor is a semiconductor device used to absorb transient overvoltages on a power line, such as the SMBJ5.0CA model, but not limited to this. Its breakdown voltage range is 5V to 6.4V. By connecting it in parallel between the input power supply terminal and ground, it can suppress the impact of voltage surges on subsequent circuits.

[0082] An inductor is an energy storage and filtering element, such as a wire-wound power inductor with an inductance range of 10μH to 47μH. It is used in conjunction with a buck converter chip to form a Buck topology, which is used to store and release energy during the switching cycle to achieve voltage conversion.

[0083] The feedback resistor network refers to a voltage divider circuit composed of resistors R24 and R25. For example, when the resistance value of R24 is 10kΩ and the resistance value of R25 is 2.2kΩ, the voltage division ratio is 2.2 / (10+2.2)=0.18. After being fed back to the FB pin of the buck converter chip, the output voltage can be kept stable at 5V.

[0084] Specifically, the input power supply is prevented from entering the buck converter chip via a diode to prevent reverse connection, and a transient voltage suppressor clamps and protects against input voltage spikes. The buck converter chip periodically turns its internal switching transistor on and off, driving an inductor to store energy and transfer it to the output. A feedback resistor network monitors the output voltage in real time; when the detected value deviates from a set threshold, the chip automatically adjusts the switching frequency or duty cycle to restore voltage stability. A filter capacitor at the output further eliminates high-frequency ripple, ensuring a continuous and stable 5V power supply to the OBD data acquisition module 100. For example, at the moment of vehicle startup, the battery voltage may drop below 8V; even then, the buck converter chip can maintain output voltage fluctuations within ±3%, ensuring the normal operation of the OBD module.

[0085] Reference Figure 9 Furthermore, the power management module 500 also includes a multi-stage voltage regulator circuit, which includes a first voltage regulator chip U1, a second voltage regulator chip U3, a current-limiting resistor R1, a rectifier diode D1, a transient voltage suppressor D2, and first filter capacitors C1, C2, C3, C4, and C5, wherein:

[0086] One end of the current-limiting resistor R1 is connected to the external input power supply VCC, and the other end is connected to the anode of the rectifier diode D1.

[0087] The cathode of the rectifier diode D1 is connected to the input terminal of the first voltage regulator chip U1, the anode of the transient voltage suppressor D2, and one end of the first filter capacitor C1;

[0088] The cathode of the transient voltage suppressor D2 is connected to ground, and the other end of the first filter capacitor C1 is connected to ground;

[0089] The first voltage regulator chip U1 is a three-terminal linear regulator, and its output terminal is connected to the second filter capacitor C2, the third filter capacitor C3 and the input terminal of the second voltage regulator chip U3;

[0090] The second voltage regulator chip U3 is a linear voltage regulator chip with an output of 3.3V, and its output terminal is connected to the fourth filter capacitor C4 and the fifth filter capacitor C5;

[0091] The first voltage regulator chip U1 outputs a 5V DC voltage, and the second voltage regulator chip U3 outputs a 3.3V DC voltage.

[0092] It should be noted that in this embodiment, the first filter capacitor C1 is only... Figure 9 The component markings in the multi-stage voltage regulator circuit shown are for illustrative purposes to illustrate the circuit connections. The first filter capacitor C1 is not the same component as the capacitor marked C1 in other embodiments of this specification; only the reference numerals are the same. Its specific structure and electrical function should be based on the descriptions in the corresponding embodiments. Those skilled in the art will understand that reference numerals with the same numbers in different embodiments are not limited to the same physical device.

[0093] Among them, a current-limiting resistor is a resistor element connected in series in the input power path, specifically a metal film resistor or a wire-wound resistor, used to limit the peak input current to prevent circuit overload. A rectifier diode is a semiconductor device with unidirectional conductivity, specifically a Schottky diode or a silicon diode, used to prevent reverse voltage from damaging the circuit. A transient voltage suppressor is a protective element that can absorb voltage spikes, specifically a TVS diode, used to suppress surge voltage or electrostatic discharge interference in the power supply line. A three-terminal linear regulator is a voltage regulator integrated circuit with three terminals: input, output, and ground, specifically an LM7805 chip, used to convert the input voltage to a stable 5V DC output. A 3.3V output linear regulator chip is a low-dropout voltage regulator device, specifically an AMS1117-3.3 chip, used to provide stable power to low-voltage logic circuits. A filter capacitor is an energy storage element connected in parallel in the power supply line, specifically a ceramic capacitor or an electrolytic capacitor, used to filter out high-frequency noise in the power supply and reduce voltage ripple.

[0094] Specifically, after the input power supply current is limited by a current-limiting resistor, it is unidirectionally conducted by a rectifier diode to prevent reverse voltage from impacting subsequent circuits. A transient voltage suppressor clamps voltage spikes at the input terminal to a safe range, protecting the voltage regulator chip from damage caused by transient overvoltage. The first filter capacitor performs initial filtering of the input power supply, and then the first voltage regulator chip stabilizes the input voltage to a 5V DC output, with further noise filtering by the second and third filter capacitors. The second voltage regulator chip further steps down the 5V input and stabilizes it to a 3.3V output, with the fourth and fifth filter capacitors performing secondary filtering on the 3.3V output. This multi-stage design, through step-by-step voltage regulation and filtering, ensures that circuit modules with different voltage requirements receive a clean and stable power supply.

[0095] Reference Figure 10 This application further proposes that the main control module 200 includes a microcontroller unit, which is equipped with an SPI bus interface, a UART serial communication interface and multiple programmable GPIO pins, wherein: the SPI interface is used for data interaction with the wireless communication module 400; the UART interface is used for receiving vehicle status information sent by the OBD data acquisition module 100 or the CANL communication module; and the GPIO pins are used to control the lighting sequence, color mode or brightness level of the indicator light unit 310 in the display module 300.

[0096] Among them, the SPI bus interface refers to a synchronous serial communication interface, which can be implemented using a full-duplex communication protocol with a four-wire structure, suitable for short-distance high-speed data transmission. The UART serial communication interface refers to an asynchronous transceiver interface, which can be implemented using a general-purpose asynchronous transceiver with flow control, suitable for data exchange with vehicle communication modules. Programmable GPIO pins refer to general-purpose input / output ports, which can be implemented using pins with direction configuration, level mode, and interrupt triggering functions, suitable for dynamically controlling the operating status of external devices.

[0097] Specifically, the microcontroller unit establishes a high-speed data channel with the wireless communication module 400 via the SPI bus interface, enabling bidirectional transmission of configuration parameters and status information. The UART serial communication interface is configured to receive real-time data streams from the vehicle bus, such as engine speed acquired via the OBD interface or vehicle speed information transmitted via the CAN bus. Multiple programmable GPIO pins are configured in output mode, controlling the on / off combinations of the indicator light units 310 in the display module 300 through preset timing logic, such as activating LEDs at different positions in ascending vehicle speed order, or switching light colors according to the power mode. This design allows the main control unit to simultaneously process multiple communication signals and precisely control the lighting display behavior.

[0098] Reference Figures 11-13Furthermore, it also includes an indicator light module, which receives preset control signals from the main control module 200 and indicates the power information and / or vehicle speed information in the form of a screen, a running light, or a color-changing light. The indicator light module includes multiple programmable RGB LEDs, an embedded driver chip U7, a constant current driver chip, a cascaded communication circuit, and a control port connected to the main control module 200, wherein:

[0099] Each RGB LED unit is connected to a single-bus input terminal via an embedded driver chip U7.

[0100] Multiple RGB LEDs are connected in a preset order to form a serial cascade structure, with the data output pin of the previous LED connected to the data input pin of the next LED.

[0101] The bus control signal is output by the main control module 200 and injected into the data input terminal of the first-stage LED after being current-limited by a resistor;

[0102] Each LED bead is connected to a 5V constant voltage output power supply, and a decoupling capacitor is connected in parallel at the power supply end to suppress power supply ripple.

[0103] The RGB LEDs are used to indicate the working status, operating mode, or current configuration of the steering wheel function keys.

[0104] Among them, programmable RGB LED beads refer to light-emitting elements capable of displaying multiple colors. Specifically, they can be implemented using LED beads with an integrated driver IC like the WS2812B, generating different colors of light by adjusting the mixing ratio of the three primary colors: red, green, and blue. Embedded driver chips are control units integrated inside the LED beads. These can be implemented using driver chips with a single-bus communication protocol, receiving serial data and controlling the brightness and color of the LED beads. Cascaded communication circuits refer to communication architectures where multiple LED beads are connected in series. This can be implemented using a single-bus cascaded topology, where data signals are transmitted from the output pins of the preceding LED bead to the input pins of the following LED bead. Decoupling capacitors are filtering components connected in parallel at the power supply end. These can be implemented using 0.1μF ceramic capacitors to filter high-frequency interference signals in the power supply line.

[0105] Specifically, the main control module 200 generates a control signal containing color encoding and brightness parameters. This signal is transmitted to the data input pin of the first-stage RGB LED via a current-limiting resistor. Each embedded driver chip parses the received data packet, extracts the corresponding instruction according to the address allocation rules, and forwards the remaining data to the next stage LED. The decoupling capacitor connected in parallel in the 5V power supply line connected to the LED power supply terminal can suppress brightness flickering caused by power fluctuations. Through this cascaded structure, the display status of multiple LEDs can be controlled with only a single signal line, reducing wiring complexity.

[0106] In some specific implementations, the number of cascaded LEDs can be 8-12, corresponding to the number of physical buttons on the steering wheel. The bus signal output by the main control module 200 can be a PWM waveform conforming to the WS2812B protocol, and the data update frequency can be 800kHz. The decoupling capacitors can be a parallel combination of 0.1μF and 10μF, used to filter out high-frequency and low-frequency noise, respectively.

[0107] Furthermore, in this embodiment, the indicator light module not only indicates the status of the steering wheel buttons but also provides a visual display of vehicle operating conditions such as engine speed and vehicle speed. The specific process is as follows: The vehicle OBD data acquisition module acquires operating parameters such as engine speed and vehicle speed in real time through the on-board diagnostic interface and wirelessly transmits them to the main control module 200 via a 2.4 GHz radio frequency communication unit. After receiving and parsing the OBD data, the main control module 200 generates a single-bus control frame containing color encoding, brightness level, and cascading address according to a preset mapping algorithm (e.g., linearly mapping 0-8000 rpm to the number of 12 LEDs lit or corresponding different speed ranges to different colors). This control frame is injected into the DIN pin of the first-stage RGB LED bead through a current-limiting resistor, and subsequent LED beads are cascaded and forwarded sequentially to achieve dynamic effects such as a running light that increases with engine speed or a ring light that changes color according to vehicle speed. Because the control frame is refreshed in real time via a wireless link, the LED indication can maintain sub-second synchronization with changes in engine speed, allowing the driver to intuitively understand the current power status without checking the instrument panel.

[0108] This application further proposes a universal steering wheel, including a custom button control device for an automotive steering wheel. The device includes multiple buttons mounted on the steering wheel, a main control module 200, a communication interface module 300, a wireless communication module 400, a power management module, and an indicator light module. The main control module 200 receives button input signals and converts them into control output signals according to a preset mapping relationship. The communication interface module 300 is electrically connected to the main control module 200 and sends signals to the vehicle system via the vehicle bus. The wireless communication module 400 establishes a communication connection between the main control module 200 and an external mobile terminal to enable custom configuration or remote updates of button functions. The power management module receives vehicle power and provides stable voltage to each module. The indicator light module includes programmable RGB LEDs and a driving circuit to indicate the button status.

[0109] The universal steering wheel refers to a multi-functional steering wheel structure that integrates a customizable button control device. This can be achieved through injection molding or modular assembly processes, and its internal layout must be compatible with the vehicle's steering system. The customizable button control device is an electronic control module that integrates button signal processing, communication protocol conversion, wireless interaction, and power management. It can be implemented using a multi-layer PCB board stacking design to address the issue of fixed functions in traditional steering wheel buttons.

[0110] Specifically, the universal steering wheel incorporates a custom button control device, allowing users to redefine button functions according to the vehicle system type or usage requirements. The main control module 200 receives input signals from the physical buttons, generates corresponding control commands based on a preset mapping relationship, and sends them to the vehicle bus, such as a CAN bus or LIN bus, via the communication interface module 300. The wireless communication module 400 can establish a connection with a mobile terminal, allowing users to configure and update button functions through a terminal application, such as redefining a button originally used for volume adjustment as a navigation shortcut. The power management module provides independent power to different functional modules through multi-stage voltage regulation circuits; for example, 5V is used to drive the communication chip, and 3.3V is used for the main control chip. The indicator light module uses RGB LED color changes to reflect the current button configuration status; for example, blue indicates the default function mode, and green indicates the user-defined mode.

[0111] Compared to existing technologies, traditional steering wheel button functions are fixed to a single vehicle system, and the hardware circuitry and communication protocols cannot be expanded. This application, however, uses a modular design to make a universal steering wheel compatible with multiple vehicle systems. Existing solutions require rewiring or ECU program modification when replacing the central control unit, while this solution utilizes a wireless communication module 400 to redefine functions at the software level, avoiding hardware modifications. Furthermore, existing steering wheels lack a status visualization feedback mechanism; this solution provides real-time operation status prompts through programmable indicator lights.

[0112] Through the above technical solutions, this application enables universal steering wheels to be adapted to different brand in-vehicle systems. Users can customize button functions via mobile terminals without hardware modifications, such as binding steering wheel buttons to frequently used operations of third-party in-vehicle applications. The multi-stage voltage regulation design of the power management module avoids communication interruptions caused by vehicle power fluctuations, ensuring stable operation of the main control module even during engine start-up. The indicator light module significantly reduces the learning curve for users through color coding; for example, flashing red indicates a button configuration conflict, while solid yellow indicates that wireless data transmission is in progress.

[0113] The above description is only used to illustrate the technical solution of this utility model and is not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of this utility model, as long as they do not depart from the spirit and scope of the technical solution of this utility model, should be covered within the scope of the claims of this utility model.

Claims

1. A custom key control device for a steering wheel of an automobile, comprising a plurality of keys mounted on the steering wheel, characterized in that, Also includes: The main control module is used to receive input signals from multiple buttons and convert the button inputs into corresponding control output signals according to a preset mapping relationship. The communication interface module is electrically connected to the main control module and is used to send the control output signal to the vehicle system through the vehicle bus; The wireless communication module is used to establish a communication connection between the main control module and an external mobile terminal, so that the user can customize the function of each button or update it remotely through the mobile terminal. The power management module is used to receive the vehicle power supply and provide a stable operating voltage for the main control module, communication interface module and wireless communication module; The OBD data acquisition module is used to acquire vehicle power information or vehicle speed information.

2. A self-defined key control device for automobile steering wheel according to claim 1, characterized in that, The communication interface module includes a CAN communication circuit and a LIN communication circuit.

3. A self-defined key control device for automobile steering wheel according to claim 2, characterized in that, The CAN communication circuit includes a CAN communication chip U6, capacitors C11, C12, and C13, and a resistor R11, wherein: The power supply pin of the CAN communication chip U6 is connected to the stable voltage provided by the power management module, and the ground pin is connected to the system ground line to provide the operating voltage for the chip. The capacitor C11 is connected between the ground pin of the chip and ground, and is used to perform high-frequency decoupling filtering on the communication chip; The capacitors C12 and C13 are connected between pin CANH and ground, and pin CANL and ground, respectively, to suppress common-mode interference and filter high-frequency noise at both ends of the CAN bus. The resistor R11 is connected between pin CANH and pin CANL and is used as a bus termination matching resistor to improve signal integrity and prevent signal reflection. The TXD and RXD pins of the CAN communication chip U6 are connected to the communication port of the main control module, respectively, to realize the data transmission and reception functions of the CAN protocol.

4. The self-defined key control device for the steering wheel of an automobile according to claim 2, characterized in that, The LIN communication circuit includes multiple LIN communication units with identical structures. Each LIN communication unit includes a LIN communication chip U4, resistor R2, resistor R3, diode D2, and capacitor C6, wherein: The transmit and receive pins of the LIN communication chip are connected to the serial communication port of the main control module, respectively, to realize the message reception and response function of the LIN bus. The VBAT pin of the LIN communication chip is connected to the vehicle's 12V power supply via connector J1 and connected in series via diode D2. The resistor R2 is connected between the VBAT pin of the LIN communication chip and the LIN bus to maintain a stable high-level state of the LIN bus. The resistor R3 is a pull-up resistor for the main control module's communication pin, used to improve the stability of the RX pin signal; The capacitor C6 is connected in parallel between the LIN bus and ground to suppress spike pulses and interference signals on the LIN line. The ground pin of the LIN communication chip is connected to system ground.

5. The self-defined key control device for the steering wheel of an automobile according to claim 1, characterized in that, The wireless communication module includes a Bluetooth communication unit and a 2.4GHz radio frequency communication unit, wherein: The Bluetooth communication unit is used to communicate with the mobile terminal and perform display mode setting, running status query and parameter configuration through the application pre-installed on the mobile terminal; The radio frequency communication unit is used to realize data exchange between the main control module and the OBD data acquisition module.

6. The self-defined key control device for the steering wheel of an automobile according to claim 1, characterized in that, The power management module includes a low-dropout linear regulator circuit for powering the wireless Bluetooth communication module. The low-dropout linear regulator circuit includes a voltage conversion chip U5, a resistor R27, and capacitors C14, C15, C16, and C17, wherein: The first terminal of the voltage conversion chip U5 is connected to a 5V power supply, one end of the resistor R27 and one end of the capacitor C16. The other end of the resistor R27 is connected to the second terminal of the voltage conversion chip U5. The other end of the capacitor C16 is connected to the third terminal of the voltage conversion chip U5, one end of the capacitor C14, one end of the capacitor C15, one end of the capacitor C17 and the ground terminal. The other ends of the capacitor C14, C15 and C17 are connected to the sixth terminal of the voltage conversion chip U5 and the power supply terminal.

7. A self-defined key control device for automobile steering wheel according to claim 6, characterized in that, The power management module includes a buck regulator circuit for powering the OBD data acquisition module. The buck regulator circuit includes a buck converter chip U3, resistors R22, R23, R24, and R25, an inductor L1, capacitors C1, C6, C7, C8, and C9, a diode D4, and a transient voltage suppressor D5. One end of resistor R22 is connected to the input power supply VIN, and the other end is connected to the positive terminal of diode D4. The negative terminal of diode D4 is connected to one end of transient voltage suppressor D5, the input terminal of buck converter chip U3, one end of resistor R23, and one end of capacitors C9 and C7. The other ends of transient voltage suppressor D5, capacitors C9 and C7 are all connected to ground. The other end of resistor R23 is connected to the enable terminal of buck converter chip U3. Pin 2 of buck converter chip U3 is connected to ground, and pin 6 of buck converter chip U3 is connected to the boost pin. Through capacitor C6, it is connected to an inductor L1 in parallel with resistor R24. The other end of inductor L1 is connected to the output terminal. Pin 1 of buck converter chip U3 is connected to the node between resistor R25 and resistor R24 ​​for feedback control. The output terminal of buck converter chip U3 is connected to output capacitors C1 and C8, and outputs a stable 5V voltage for use by the OBD data acquisition module.

8. The self-defined key control device for the steering wheel of an automobile according to claim 7, characterized in that, The power management module further includes a multi-stage voltage regulator circuit, which includes a first voltage regulator chip U1, a second voltage regulator chip U3, a current-limiting resistor R1, a rectifier diode D1, a transient voltage suppressor D2, and first filter capacitors C1, C2, C3, C4, and C5, wherein: One end of the current-limiting resistor R1 is connected to the external input power supply VCC, and the other end is connected to the anode of the rectifier diode D1. The cathode of the rectifier diode D1 is connected to the input terminal of the first voltage regulator chip U1, the anode of the transient voltage suppressor D2, and one end of the first filter capacitor C1; The cathode of the transient voltage suppressor D2 is connected to ground, and the other end of the first filter capacitor C1 is connected to ground; The first voltage regulator chip U1 is a three-terminal linear regulator, and its output terminal is connected to the second filter capacitor C2, the third filter capacitor C3 and the input terminal of the second voltage regulator chip U3; The second voltage regulator chip U3 is a linear voltage regulator chip with an output of 3.3V, and its output terminal is connected to the fourth filter capacitor C4 and the fifth filter capacitor C5; The first voltage regulator chip U1 outputs a 5V DC voltage, and the second voltage regulator chip U3 outputs a 3.3V DC voltage.

9. The self-defined key control device for the steering wheel of an automobile according to claim 1, characterized in that, It also includes an indicator light module, which receives preset control signals from the main control module and indicates the power information and / or vehicle speed information in the form of a screen, a running light, or a color-changing light. The indicator light module includes multiple programmable RGB LEDs, an embedded driver chip U7, a constant current driver chip, a cascaded communication circuit, and a control port connected to the main control module, wherein: Each RGB LED unit is connected to a single-bus input terminal via an embedded driver chip U7. Multiple RGB LEDs are connected in a preset order to form a serial cascade structure, with the data output pin of the previous LED connected to the data input pin of the next LED. The bus control signal is output by the main control module and injected into the data input terminal of the first-stage LED after being current-limited by a resistor; Each LED bead is connected to a 5V constant voltage output power supply, and a decoupling capacitor is connected in parallel at the power supply end to suppress power supply ripple. The RGB LEDs are used to indicate the working status, operating mode, or current configuration of the steering wheel function keys.

10. A universal steering wheel, characterized by Includes the custom button control device for an automobile steering wheel as described in any one of claims 1-9.

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