#The 7th Lichuang Electric Competition#The Mountaintop Light Ferris Wheel

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* 1. Project function introduction
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    There is a legend about the Ferris wheel. Lovers who ride the Ferris wheel together will eventually break up, but when the Ferris wheel reaches the highest point, if you kiss your lover, you will go on forever. Legend has it that every box of the Ferris wheel is filled with happiness.
    When you look up at the Ferris wheel, you are looking up at happiness. The higher the happiness is, the higher the Ferris wheel is. When you are eager to get happiness but happiness has not arrived yet, try to sit on the Ferris wheel and wait for it to rise slowly until it reaches the top, looking down at everything you see. In fact, the happiness you want is very simple.
    This is this year, that is, May 3, 2022. I remember this day very clearly. It was the first time I went on the Ferris wheel with my wife. When I saw it, the first feeling was that the lights were very cool and it was rotating slowly at the same time. The people sitting inside must be very happy. As an engineering student, I was thinking whether I could imitate the function and structure of this Ferris wheel and give it to her, because she often complained that I had never taken her to ride the Ferris wheel. It would definitely be very happy to put it at home. The picture below shows the Ferris wheel in Chongqing Entertainment Town. The photo may look ordinary, but the effect on site is absolutely shocking.
    Next is the mountaintop light Ferris wheel designed by myself. Through SolidWorks drawing, mechanical design, 3D printing, circuit diagram drawing, PCB board making, hardware circuit welding, stm32 bottom development, Android program development, it took about 3 months. Of course, I took time to do it. Finally, the design was completed, as shown in the figure below.
 
 
 
 
 
 
 
    The function of the mountaintop light Ferris wheel is realized through single-chip microcomputer, 3D printing and mobile phone mobile terminal control to realize the power control system and lighting control system of the Ferris wheel, including but not limited to text, animation, pictures and real-time time display.
    It can be used indoors, outdoors at night and in shopping malls to increase the sense of happiness in family and life, and can be used for the expression and transmission of love between lovers. At the same time, the project adopts modular design, and primary school students can also assemble it easily, and cooperate with mobile software to realize the magical and attractive Ferris wheel function, so it is also suitable for the current primary school students' science and innovation courses, and can also be used as a training kit for college students, such as single-chip computer training courses, for modern teaching. All functions are shown in the mind map, as shown in the figure below.
Figure 5 Mind map of the function of the Ferris wheel of the light of the mountain
 
Note: The theme is not limited, it can be a solution to a problem in life/work, a solution designed for a certain group of people/scenes, a graduation project/course design/DIY project/purely cool project, etc. Mainly talk about what means you have solved what problem.
 
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Original work, not published
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Note: Altruism is self-interest, please read the following content carefully.
Embrace open source and give the project unlimited value. It is recommended that more than 80% of the core functions of the project be open source;
if a part of the functions is irreplaceable and the project cannot solve the corresponding problem after deleting it, then the functions implemented by this part are the core functions of the project; for example, if an electronic load is designed and a host computer software is designed to monitor power changes, the electronic load is the core function and the host computer software is an auxiliary function; for example, an isolated 485 module is used in the electronic load to communicate with the host computer, then the communication function implemented by this 485 module is an auxiliary function;
the project should choose an open source protocol that suits it. If the project quotes other open source projects, the source should be indicated and the original author's open source protocol regulations should be followed; original projects are recommended to use the GPL3.0 open source protocol;
functions implemented by directly quoting the original circuit or original code of the open source project cannot be used as the core functions of your own project, and functions directly implemented using general modules on the market cannot be used as the core functions of your own project.
 
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4.1 Ferris wheel core board
Figure 6 Ferris wheel core board circuit diagram
1. stm32f103c8t6
    The core control board of the entire Ferris wheel, including motor drive, ws2812b color light drive, data communication and other functions.
2. DRV8833PWPR motor driver chip
    drives 5V motor, supports PWM speed regulation, motor forward and reverse rotation. The motor used for the Ferris wheel power drive is N20 reduction motor, 6V10 rpm, 1::1000, torque 2.2kg.
Figure 7 N20 reduction motor
3. ds3231 high-precision clock chip
    is used to realize the function of obtaining the current real-time time of the hardware device. The module device contains a battery input terminal, which can still maintain accurate timing when the main power is disconnected. The integrated micro-electromechanical system (MEMS) improves the long-term accuracy of the device and reduces the number of components in the production line.
4. USR-C216 WiFi module of Youren Technology
Figure 8 USR-C216 WiFi module of Youren Technology
    is used for data communication between mobile APP and underlying hardware board, and supports NTP time function. After connecting to the network, it can automatically obtain network time.
5. Supports four-way ws2812b color light control interface
    Ferris wheel PCB core board circuit diagram and 3d view, as shown below.
Figure 9 Ferris wheel core board pcb board
Figure 10 Ferris wheel core board 3D view
  The Ferris wheel PCB core board is shown below.
 
4.2 Ferris wheel RGB quarter pattern disc
    Why should the 360-degree pattern disc be split into a quarter of a small arc? Here is a little trick for the design of this project. This design can save costs very well. If it is made as a whole, it will be expensive. By patchwork, 4 pieces of the same PCB can form a large ring, which not only saves costs, but also achieves the control function of each lamp bead. All these are the design features of the PCB of this project for reference by other designers.
Figure 11 RGB disc 8x8 lamp beads connection
   A quarter RGB disc uses 8*8=64 ws2812b lamp beads, and the 360-degree disc is evenly divided into 4 parts, so the entire matrix disc will use 8*8*4=256 lamp beads.
Figure 12 RGB disc arc lamp bead connection
    From Figure 12, it can be seen that the control signal line of the arc lamp here is controlled separately from the 8*8 matrix control signal line, which is convenient for the subsequent display of various animations. There are 10 ws2812b lamp beads, and a total of 4*10=40 lamp beads will be used.
    Therefore, the entire top light Ferris wheel will use 8*8*4+4*10=296 lamp beads, and they can all be controlled independently.
    The Ferris wheel disc pcb circuit diagram and 3d view are shown in the figure below.
Figure 13 Disc pcb circuit diagram
Figure 14 Disc pcb 3d view
4.3 Ferris wheel SolidWorks mechanical design
 
Figure 15 Side view of the light on the top of the mountain
Figure 16 Right view of the light on the top of the mountain
Figure 17 Front view of the light on the top of the mountain
Figure 18 Left view of the light on the top of the mountain
    The mechanical design structure is also one of the difficulties of this project, because it involves the problem of twisted wires. To solve the problem of twisted wires, it is necessary to analyze the transmission structure of the Ferris wheel in detail. The power lines of the Ferris wheel disc lamp beads and the Ferris wheel cabin lamp beads, as well as the control signal lines, need to be connected to the stm32 core control board, but the Ferris wheel disc is always rotating. If this problem is not handled properly, the pattern display and lighting control of the Ferris wheel will not be realized.
    Simply put, add a conductive ring, a deep groove ball bearing, and a conductive ring fixing cover on the shaft. The three work together to prevent twisted wires. For the specific structure, please refer to the video demonstration below.
Figure 19 Shaft + deep groove ball bearing + conductive ring fixed cover structure
 
Figure 20 Conductive ring and deep groove ball bearing connection structure
4.4 Ferris wheel 3D printing file drawings
Figure 21 Base 1
Figure 22 Base 2
Figure 23 Upper cabin box
 
Figure 24 Ferris wheel disc
Figure 25 Shaft
Figure 26 Cockpit
 
Note: It is recommended to use Jiali Chuang EDA. If you choose other EDA tools, please upload the schematic diagram in PDF format, PCB drawings in PDF format, and PCB files in Gerber format in the attachment. Here you can explain in detail the implementation principle and mechanism of your project, precautions, debugging methods, testing methods, etc. It is recommended to introduce your ideas to others in the form of pictures and texts.
 
*5.
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5.1 Ferris wheel core board program
1.ws2812 control schematic
diagram 27 ws2812b lamp bead timing waveform diagram
Figure 28 ws2812b data transmission method
    The above is mentioned in the data manual. The WS2812 driver uses a single-line return-to-zero code communication method. Square waves with different duty cycles represent 1 code or 0 code. Here, different duty cycles are 0 code or 1 code high level time/square wave cycle time. For this routine, we change the duty cycle of PWM to achieve the transmission of 0 code or 1 code.
    Here, PWM+DMA is used to drive the WS2812 lamp beads. It can realize pulses with controllable quantity and duty cycle. The specific implementation principle is that when DMA is turned on, the timer will automatically use the data transmitted by DMA as the new round of comparison value after each count. If the data transmitted by DMA is different each time, the duty cycle of the square wave will be different each time. In this routine, we store the data in an array and transmit the contents of the array through DMA. According to the number of data in the array and the size of each data, PWM with controllable quantity and duty cycle can be realized.
5.2 Mobile terminal program design
    The mobile terminal program is developed using Android Studio software. After the mobile phone is connected to the WiFi module, the Ferris wheel can be controlled locally or remotely through the APP software, combining entertainment and life. The functions include color control, lighting control, clock control, graphic display and scenario mode. Due to the tight time, the mobile terminal functions are still being improved and updated. The functional interface is shown in the figure below.
Figure 29 Software User Center
 
 
Figure 30 Color Control
 
 
Figure 31 Lighting Control
 
 
Figure 32 Clock Control
 
 
Figure 33 Graphic Display
 
 
Figure 34 Scenario Mode
Note: If your project involves software development, please upload the corresponding project source code in the attachment. Here you can explain in detail your software flow chart, functional module block diagram, explanation or popular science of related algorithms, source code structure, compilation environment construction and configuration, source code compilation method, program burning method, etc. It is recommended to introduce your ideas to others in the form of pictures and texts.
 
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Ferris wheel core board BOM table
Peak Light Ferris wheel quarter disk BOM table
Note: The BOM list involved in the project. Please upload a screenshot of the BOM in this position. Please upload the list details in PDF format to the attachment. It is recommended to include model, brand, name, package, procurement channel, purpose and other content. The specific content and form should be based on the clear expression of the project composition.
 
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please upload a project picture containing the competition logo. The logo is printed on the PCB in silk screen form.
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* 8. Demonstrate your project and record it into a video. Upload
 
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video title: LiChuang Electric Race: {Project Name}-{Video Module Name}; such as LiChuang Electric Race: "Autonomous Driving"-Team Introduction.
 
More details: https://diy.szlcsc.com/posts/d76d9cb41705430e9a54e7a5feed07a5