Intelligent audio playing system and method based on original vehicle disc box interface

Abstract

The invention discloses an intelligent audio playing system and method based on an original vehicle disc box interface, and belongs to the technical field of automotive electronics. The intelligent audio playing system comprises a main control module, an audio processing module, a power supply module, a storage interface module, a Bluetooth module and an audio output module, the main control module is electrically connected with the audio processing module, the storage interface module, the Bluetooth module and the audio output module, the output end of the power module is electrically connected with the input end of the main control module, and the output end of the Bluetooth module is electrically connected with the input end of the audio processing module. The output end of the audio processing module is electrically connected with the input end of the audio output module. The system can be seamlessly integrated to an original vehicle sound system, a disc box interface and a control button of an original vehicle are reused, the capability of playing high-quality digital audio through a USB flash disk or Bluetooth is provided for a user, and low-cost and high-performance upgrading of sound functions of old vehicle types is achieved.

Description

Technical Field

[0001] This invention belongs to the field of automotive electronics technology, and in particular relates to an intelligent audio playback system and method based on the original car CD changer interface. Background Technology

[0002] Currently, many cars manufactured between 2007 and 2013 come equipped with original car audio head units (car stereos) that include CD playback functionality and a standard disc tray interface. As vehicles age (up to 10-20 years), the electronic equipment, especially mechanical components like the CD player, is prone to aging and wear, causing malfunctions and preventing owners from enjoying music through the original car audio system. While owners can replace the entire head unit to gain modern features like Bluetooth and USB, this method is expensive and may damage the original interior design and wiring.

[0003] There are some music players on the market that connect via FM transmitter or AUX interface, but these solutions have obvious drawbacks: FM transmitters have poor sound quality and are easily interfered with; AUX interfaces require manual switching of audio sources and cannot be controlled via the original car steering wheel or panel buttons, which is inconvenient to operate and affects driving safety. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that the original car steering wheel or panel buttons cannot be used for control, which is inconvenient to operate and affects driving safety. Therefore, this invention proposes an intelligent audio playback system and method based on the original car CD changer interface.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A smart audio playback system based on the original car CD changer interface includes a main control module, an audio processing module, a power supply module, a storage interface module, a Bluetooth module, and an audio output module. The main control module is electrically connected to the audio processing module, the storage interface module, the Bluetooth module, and the audio output module. The output terminal of the power supply module is electrically connected to the input terminal of the main control module. The output terminal of the Bluetooth module is electrically connected to the input terminal of the audio processing module. The output terminal of the audio processing module is electrically connected to the input terminal of the audio output module.

[0006] As a further description of the above technical solution: The main control module uses two 32-bit ARM Cortex-M series MCUs. MCU-1 is specifically responsible for simulating the communication protocol of the original car CD changer and exchanging data with the vehicle host, such as receiving IN and CLK signals and sending OUT data. MCU-2 is responsible for managing the system status, such as detecting USB flash drive insertion, controlling Bluetooth connection status, and parsing user commands. The two MCUs work together to improve the system's processing efficiency and reliability.

[0007] As a further description of the above technical solution: The audio output module uses a dedicated audio DSP chip (aDSP) from Cirrus Logic or TI.

[0008] As a further description of the above technical solution: The chip receives digital audio data from a USB flash drive or Bluetooth via the main control module through the I2S bus and decodes it. It supports full bitrate decoding of multiple formats such as MP3, WAV, FLAC, and APE.

[0009] As a further description of the above technical solution: The power module has an input voltage of DC 8V-14.6V, compatible with fluctuations in car battery voltage. Internally, it uses a DC-DC isolated power chip to convert and isolate the input 12V power into a clean power supply for both the digital and analog sections.

[0010] As a further description of the above technical solution: The storage interface module is a standard USB-A female connector that supports the FAT32 file system and can recognize USB flash drives up to 128GB.

[0011] As a further description of the above technical solution: The Bluetooth module uses a CSR8670 or similar Bluetooth 5.0 chip, supports protocols such as A2DP audio transmission, AVRCP remote control, and HFP hands-free calling, and communicates with the main control module via UART serial port.

[0012] As a further description of the above technical solution: The audio output module outputs analog audio signals for the left and right channels from the PCM data decoded by the audio DSP through a high-performance digital-to-analog converter and a high-quality operational amplifier circuit. The signals are then directly connected to the corresponding pins of the disc tray interface via low-impedance lines.

[0013] A method for an intelligent audio playback system based on the original car CD changer interface specifically includes the following steps: S1. The vehicle is powered on, and the system starts initialization. S2. The main control module sends a ready signal to the vehicle host through the disc tray interface to simulate the presence of a CD changer; S3. When the user presses the "CD" or "DISC" button on the vehicle's infotainment system, the system enters disc mode. S4. The main control module detects whether a USB flash drive is inserted. If yes, it enters S5 (USB flash drive mode); otherwise, it enters S7 (Bluetooth mode). S5. Read the audio file from the USB drive, start playing it, and light up the corresponding status indicator light, such as a slow flashing red light; S6. During playback, continuously monitor for Bluetooth connection requests or audio streams. If any are found, proceed to S7. S7. The Bluetooth module enters a discoverable and connectable state, waiting for mobile phones and other devices to pair and connect. S8: Bluetooth connection successful, and the system will play Bluetooth audio as soon as an audio stream is input; S9. Throughout the process, the system analyzes the control signals received from the disc tray interface in real time, such as knob rotation and button pressing, and performs corresponding operations according to the preset mapping table, such as changing songs, switching audio sources, and answering phone calls.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention can be seamlessly integrated into the original car audio system, reuse the original car's CD changer interface and control buttons, and provide users with the ability to play high-quality digital audio via USB flash drive or Bluetooth, achieving low-cost, high-performance upgrade of the audio functions of older car models.

[0015] 2. This invention directly utilizes the original vehicle's pre-reserved disc tray interface, without damaging any original vehicle wiring, achieving a "plug and play" non-destructive installation. It is perfectly compatible with all relevant control buttons in the original vehicle, such as steering wheel control buttons and head unit panel buttons, providing an operating experience consistent with the original equipment. Through the dual technical protection of "dedicated audio DSP hardware decoding" and "isolated power supply", it effectively reduces background noise and interference, has a wide frequency response, high signal-to-noise ratio, and can reproduce pure and delicate sound.

[0016] 3. This invention supports functions such as automatic audio source detection, automatic switching (e.g., automatically switching from USB flash drive to Bluetooth call when a call comes in), folder management, and breakpoint memory, which greatly improves the user's convenience and allows the audio system of old car models to be revitalized at a low cost, enjoying the same digital music convenience as modern new cars, and extending the service life of the original car audio system. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the system structure of an intelligent audio playback system and method based on the original car disc drive interface proposed in this invention; Figure 2 This is a circuit diagram of the main control module of an intelligent audio playback system and method based on the original car disc player interface proposed in this invention. Figure 3 This is a circuit diagram of the audio processing module of an intelligent audio playback system and method based on the original car disc player interface proposed in this invention. Figure 4This is a circuit diagram of the power module of an intelligent audio playback system and method based on the original car disc player interface proposed in this invention. Figure 5 This is a circuit diagram of the storage interface module of an intelligent audio playback system and method based on the original car disc drive interface proposed in this invention. Figure 6 This is a circuit diagram of the Bluetooth module of an intelligent audio playback system and method based on the original car CD changer interface proposed in this invention. Figure 7 This is a circuit diagram of the audio output module of an intelligent audio playback system and method based on the original car disc drive interface proposed in this invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Please see Figure 1-7 This invention provides a technical solution: an intelligent audio playback system based on the original car CD changer interface, including a main control module, an audio processing module, a power supply module, a storage interface module, a Bluetooth module, and an audio output module. The main control module is electrically connected to the audio processing module, the storage interface module, the Bluetooth module, and the audio output module. The output terminal of the power supply module is electrically connected to the input terminal of the main control module. The output terminal of the Bluetooth module is electrically connected to the input terminal of the audio processing module. The output terminal of the audio processing module is electrically connected to the input terminal of the audio output module.

[0020] The main control module uses two 32-bit ARM Cortex-M series MCUs. MCU-1 is specifically responsible for simulating the communication protocol of the original car CD changer and exchanging data with the vehicle host, such as receiving IN and CLK signals and sending OUT data. MCU-2 is responsible for managing the system status, such as detecting USB flash drive insertion, controlling Bluetooth connection status, and parsing user commands. The two MCUs work together to improve the system's processing efficiency and reliability.

[0021] The audio output module uses a dedicated audio DSP chip (aDSP) from Cirrus Logic or TI. This chip receives digital audio data from a USB flash drive or Bluetooth via the main control module through the I2S bus and decodes it. It supports full bitrate decoding of multiple formats such as MP3, WAV, FLAC, and APE, ensuring the authenticity of the audio reproduction.

[0022] The power module has an input voltage of DC 8V-14.6V, compatible with car battery voltage fluctuations. Internally, it employs a DC-DC isolated power chip to convert and isolate the input 12V power into clean power for both the digital and analog sections. Digital and analog grounds are strictly separated on the PCB layout, with a single-point connection only at the isolation power supply, fundamentally cutting off noise conduction paths.

[0023] The storage interface module is a standard USB-A female connector that supports the FAT32 file system and can recognize USB flash drives up to 128GB. The main control module scans the root directory of the USB flash drive, identifies folders starting with "01.", "02."... "99.", and plays them sequentially.

[0024] The Bluetooth module uses a CSR8670 or similar Bluetooth 5.0 chip, supports protocols such as A2DP audio transmission, AVRCP remote control, and HFP hands-free calling, and communicates with the main control module via UART serial port.

[0025] The audio output module outputs analog audio signals for the left and right channels from the PCM data decoded by the audio DSP through a high-performance digital-to-analog converter and a high-quality operational amplifier circuit. The signals are then directly connected to the corresponding pins of the disc tray interface via low-impedance lines.

[0026] A method for an intelligent audio playback system based on the original car CD changer interface specifically includes the following steps: S1. The vehicle is powered on, and the system starts initialization. S2. The main control module sends a ready signal to the vehicle host through the disc tray interface to simulate the presence of a CD changer; S3. When the user presses the "CD" or "DISC" button on the vehicle's infotainment system, the system enters disc mode. S4. The main control module detects whether a USB flash drive is inserted. If yes, it enters S5 (USB flash drive mode); otherwise, it enters S7 (Bluetooth mode). S5. Read the audio file from the USB drive, start playing it, and light up the corresponding status indicator light, such as a slow flashing red light; S6. During playback, continuously monitor for Bluetooth connection requests or audio streams. If any are found, proceed to S7. S7. The Bluetooth module enters a discoverable and connectable state, waiting for mobile phones and other devices to pair and connect. S8: Bluetooth connection successful, and the system will play Bluetooth audio as soon as an audio stream is input; S9. Throughout the process, the system analyzes the control signals received from the disc tray interface in real time, such as knob rotation and button pressing, and performs corresponding operations according to the preset mapping table, such as changing songs, switching audio sources, and answering phone calls.

[0027] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A smart audio playback system based on the original car CD changer interface, characterized in that, It includes a main control module, an audio processing module, a power supply module, a storage interface module, a Bluetooth module, and an audio output module. The main control module is electrically connected to the audio processing module, the storage interface module, the Bluetooth module, and the audio output module. The output terminal of the power supply module is electrically connected to the input terminal of the main control module. The output terminal of the Bluetooth module is electrically connected to the input terminal of the audio processing module. The output terminal of the audio processing module is electrically connected to the input terminal of the audio output module.

2. The intelligent audio playback system based on the original car CD changer interface according to claim 1, characterized in that, The main control module uses two 32-bit ARM Cortex-M series MCUs. MCU-1 is specifically responsible for simulating the communication protocol of the original car CD changer and exchanging data with the vehicle host, such as receiving IN and CLK signals and sending OUT data. MCU-2 is responsible for managing the system status, such as detecting USB flash drive insertion, controlling Bluetooth connection status, and parsing user commands. The two MCUs work together to improve the system's processing efficiency and reliability.

3. The intelligent audio playback system based on the original car CD changer interface according to claim 1, characterized in that, The audio output module uses a dedicated audio DSP chip from Cirrus Logic or TI.

4. The intelligent audio playback system based on the original car CD changer interface according to claim 3, characterized in that, The chip receives digital audio data from a USB flash drive or Bluetooth via the main control module through the I2S bus and decodes it. It supports full bitrate decoding of multiple formats such as MP3, WAV, FLAC, and APE.

5. The intelligent audio playback system based on the original car CD changer interface according to claim 1, characterized in that, The power module has an input voltage of DC 8V-14.6V, compatible with fluctuations in car battery voltage. Internally, it uses a DC-DC isolated power chip to convert and isolate the input 12V power into a clean power supply for both the digital and analog sections.

6. The intelligent audio playback system based on the original car CD changer interface according to claim 1, characterized in that, The storage interface module is a standard USB-A female connector that supports the FAT32 file system and can recognize USB flash drives up to 128GB.

7. The intelligent audio playback system based on the original car CD changer interface according to claim 1, characterized in that, The Bluetooth module uses a CSR8670 or similar Bluetooth 5.0 chip, supports protocols such as A2DP audio transmission, AVRCP remote control, and HFP hands-free calling, and communicates with the main control module via UART serial port.

8. The intelligent audio playback system based on the original car CD changer interface according to claim 1, characterized in that, The audio output module outputs analog audio signals for the left and right channels from the PCM data decoded by the audio DSP through a high-performance digital-to-analog converter and a high-quality operational amplifier circuit. The signals are then directly connected to the corresponding pins of the disc tray interface via low-impedance lines.

9. A method for an intelligent audio playback system based on the original car CD changer interface according to any one of claims 1-8, characterized in that, Specifically, the following steps are included: S1. The vehicle is powered on, and the system starts initialization. S2. The main control module sends a ready signal to the vehicle host through the disc tray interface to simulate the presence of a CD changer; S3. When the user presses the "CD" or "DISC" button on the vehicle's infotainment system, the system enters disc mode. S4. The main control module detects whether a USB flash drive is inserted. If yes, it enters S5 (USB flash drive mode); otherwise, it enters S7 (Bluetooth mode). S5. Read the audio file from the USB drive, start playing it, and light up the corresponding status indicator light, such as a slow flashing red light; S6. During playback, continuously monitor for Bluetooth connection requests or audio streams. If any are found, proceed to S7. S7. The Bluetooth module enters a discoverable and connectable state, waiting for mobile phones and other devices to pair and connect. S8: Bluetooth connection successful, and the system will play Bluetooth audio as soon as an audio stream is input; S9. Throughout the process, the system analyzes the control signals received from the disc tray interface in real time, such as knob rotation and button pressing, and performs corresponding operations according to the preset mapping table, such as changing songs, switching audio sources, and answering phone calls.

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