Magic engraved version of walnut shake

The mechanical structure comes from: Station B@witty Kason. 3D drawings improve upon it.
Circuit functions include: lithium battery protection circuit, charging circuit, power display circuit, PWM speed regulation function, Class D power amplifier, Bluetooth audio module, voice playback circuit, wave sensor radar module, 4-channel ten-digit bandpass filter spectrum light control circuit.
 
Video - Production tutorial: https://www.bilibili.com/video/BV1t24y1f77W
 
Supplementary time: 2023-02-21   
Supplementary content: 3D drawings of cushion mold
 
Correction time: 2022-12-10
@StarrySky: PMOS for power switching The source and drain terminals are reversed. When there is 5V, power will be poured from the internal parasitic diode to the battery.
Thanks to netizens for correcting me. When the PMOS tube (Q2) is connected to an external voltage of 5V, it will indeed be fed back to the positive terminal of the battery through the parasitic diode. Actual adjustment will The source S and drain D of the PMOS tube component are reversed and the problem is solved.
The schematic diagram and PCB file have been modified, and the electronic data file has been re-uploaded.
Friends who have made the board before, it is recommended to turn the PMOS tube component over during actual welding, and then weld after the positions of pins 2 and 3 are reversed. Question Can be solved.
We apologize for the inconvenience this has caused you!
 
In terms of 3D drawings, the bearings were replaced with 2mm diameter stainless steel optical shafts, and the corresponding hole positions in the 3D drawings were also adjusted. The drive motor was replaced with an M10 planetary reduction motor.
 
Power supply part: including lithium battery protection circuit, lithium battery charging circuit, lithium battery power display circuit, and power supply line switching circuit.
When using battery power supply (VBAT), the R5 pull-down resistor pulls the gate level of the PMOS tube low, the PMOS tube is turned on, and the battery supplies power to the system.
When TYPE-C is powered (5V), the PMOS tube gate level is pulled up to 5V, the PMOS tube is turned off, the battery stops supplying power to the system, and the 5V power supply supplies power to the system through diode D1.
Because the VCC voltage is higher than the VBAT voltage, the battery power will not flow into VCC through the parasitic diode of the PMOS tube.
 
The PWM speed regulation function is generated by the oscillation of the NE555 time base circuit. By setting the capacitance value of C16 and the resistance value of the adjustable resistor RP1, the frequency range setting can be achieved.
The output duty cycle can be adjusted by changing the resistance of the adjustable resistor RP1, terminals 1-2 and 2-3.
For music storage and playback functions, please refer to the attached chip information.
For power amplifier circuit, Bluetooth audio module, wave sensor radar module, etc., please refer to the relevant information in the attachment.
 
It is recommended to refer to the following figure for the circuit welding sequence.
The Bluetooth audio module ground (AGND1 pin) needs to be connected to the power amplifier ground (AGND pin) separately. This can basically eliminate the current sound when playing Bluetooth music.
 
 
The spectrum light circuit uses multiple feedback bandpass filtering and cooperates with the audio level indicator chip LM3915 to achieve visual display of a specific spectrum range.
 
Open source materials include:
1. 3D model drawings
2. Flat printing drawings (can be printed on ordinary photo paper or PVC plastic sheet, recommended thickness 0.2mm)
3. Electronic data (including: related chip data, schematics, etc.)
4. BOM Checklist