Liao Yinghui, Zhao Dongmei, Liang Yunyan: Small music player
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This post was last edited by 18371403691 on 2018-9-1 19:49 Small Music Player Abstract Music player is a multimedia player software used to play music files, that is, the visual operation interface of the audio decoder. Its essence is a decoder for various audio decoding formats. Its humanization and extensibility are its characteristics. This group of works is divided into three modules: single-chip control module, power module, and power amplifier module. The single-chip module uses the STC89C52 chip as the control core and acts as the sound source; the power module is a 5V regulated DC power supply, which is composed of light-emitting diodes, power transformers, etc., to provide stable power supply for the player; the power amplifier module uses the LM386 chip as the core, which plays the role of amplifying sound, and the sound is stable and less noise. This group of works has stable performance and can play the specified song after amplification. Keywords:MCU module; power amplifier; power supply ABSTRACT The music player is a multimedia playback software for playing music files, that is, the visual interface of the audio decoder, which is the essence of the decoder for all kinds of audio decoding formats, and its humanization and extensibility are its features. There are three modules in this group: SCM control module, power module and power module. The MCU module uses STC89C52 chip as the control core and serves as the sound source; the power module is composed of 5V stable voltage DC power supply, which is composed of light emitting diode and power transformer to provide a stable power supply for the player; the amplifier module takes the LM386 chip as the core, amplifies the sound, and the sound is stable and the noise is less. The performance of this group is stable, and it can play the specified songs after enlargement. [align] =left]Key words: Single chip module; power amplifier; power supply Contents [a lign=left]3.1.1 Shell 4[ url=#_Toc8901_WPSOffice_Level2]3.3 Power Module 4[/url] 1. Introduction Music players are popular among the general public for their beautiful interface and simple operation. However, the good products of this type on the market are not cheap, so we thought of making a small music player by ourselves, converting a piece of music notation into hexadecimal music that can be recognized by the microcontroller, inputting it into the chip of the C51 microcontroller, and then using a self-made power amplifier to amplify the sound and play it out, so as to achieve the purpose of playing the specified track. The self-made music player has low cost and is very convenient to use. Our group mainly focuses on the welding of the power amplifier, constantly looking for materials with more suitable specifications to make the sound clearer and without noise, so as to maximize the reproduction of the original sound. 2. Comparison and demonstration of solutions 2.1 Comparison of solutions This section mainly discusses the selection and demonstration of the power amplifier module. Solution 1: DTA7294. The chip adopts a 15-pin dual-row asymmetric plug-in package, the differential input stage is composed of bipolar transistors, and the driving stage and power output stage adopt DMOS field effect tube semiconductor technology. This hybrid semiconductor manufacturing process allows DTA7294 to take into account the advantages of bipolar signal processing circuits and MOS power tubes, and the playback sound is very friendly, and it is known as the "tube-flavored power amplifier"; the built-in silent standby function, short-circuit current and overheating protection functions make its performance more perfect. It can be used in HiFi home audio, active audio, high-performance TV sets and other fields. Scheme 2: LM386 is an audio integrated amplifier with the advantages of low power consumption, adjustable internal chain gain, wide power supply voltage range, few external components and total harmonic distortion. It is widely used in recorders and radios. 2.2 Scheme Selection TDA7294 has a soft and natural sound, high fidelity, very simple and soft, but the bass strength is a little poor. LM386 has a soft and beautiful sound, good bass strength, full and thick, which is better than TDA7294, and is more suitable for driving small-caliber bookshelf boxes. In general, the sound of LM386 is thick, but a little faint; TDA7294 is clearer, but the strength seems not enough. Comprehensive consideration, LM386 is more in line with the requirements of this group of works. 2.3 Scheme Demonstration This work is controlled by a combination of a single-chip control module, a power supply module and an amplifier module. 3. System Hardware Design 3.1 System Mechanical Production 3.1 ... 373226 373227 373228 373229 3.2.1 Minimum system board 3.3 Power supply module 5V DC regulated power supply 4.System software design 4.1 System control diagram file:///C:\Users\lenovo\AppData\Local\Temp\ksohtml\wpsE8B7.tmp.jpg file:///C:\Users\lenovo\AppData\Local\Temp\ksohtml\wpsE8C7.tmp.jpg file:///C:\Users\lenovo\AppData\Local\Temp\ks ohtml\wpsE8C8.tmp.jpg file:///C:\Users\lenovo\AppData\Local\Temp\ksohtml\wpsE8C9.tmp.jpg 5. Test plan and test results 5.1 Test instrument Multimeter,51 single-chip microcomputer 5.2 Test method Use a multimeter to test whether there is any cold soldering on the components on the breadboard, and use51 single-chip microcomputer to detect whether the program is correct through the buzzer. 5.3 Test results There is no cold soldering phenomenon in each component, and the program runs normally. 6. Test analysis and summary 6.1 Test analysis 1. The power amplifier module can play sound after welding, but due to the specification of the selected materials, there is a lot of noise. After replacing the components with more suitable specifications, the sound is clearer and the expected effect is better achieved. 2. The single-chip control module is the sound source. In the early stage of program writing, there was a problem with the loop, which caused the music to play disorderly. After the improvement, both songs can be played normally. 6.2 Summary The amplifier can play the selected songs clearly, and the written program runs well, so both songs can be played well. References Guo Tianxiang. "New Concept 51 Single-Chip Microcomputer C Language Tutorial", Electronic Industry Press, December 2012 Appendix file:///C:\Users\lenovo\AppData\Loca l\Temp\ksohtml\wpsE8DA.tmp.pngAppendix 1: Mechanical installation diagram of the devicefile:///C:\Users\lenovo\AppData\Local\Temp\ksohtml\wpsE8DB.tmp.pngfile:///C:\Users\lenovo\AppData\Local\Temp\ksohtml\wpsE8EC.tmp.png Figure 1 Overall structure diagram Appendix 2: List of main components Name | | | | | | | | | | Four-legged vertical induction cooker touch switch | | | | | | | | | | | | [align =left]33pF | [align=right ] 2 | Bread PCB circuit board[/align ] | | | | | | | | | | [ align=left]Male to female/female to female [/td][td =131][/td ][/tr] | | | |
[/font ] 8mm 100g[/td][td=131][/td][/tr] [tr][td=175][/td][td=178]Male to Female/Female to Female 3.5mm male to male [ /align][/td][td=131] [/td][/tr] [/table] 8mm 100g Male to Female/Female to Female 3.5mm male to male [ /align][/td][td=131] [/td][/tr] [/table]
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