Magic engraved version walnut shake

Mechanical structure from: Station B @ Clever Kason. 3D drawings have improved 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-way ten-bit bandpass filter spectrum lamp control circuit.

Video - Making tutorials: https://www.bilibili.com/video/BV1t24y1f77W

Supplement: 2023-02-21

Supplemental content: 3D drawings of cushion molds.

Corrected on: 2022-12-10

@StarrySky: The PMOS source drain of the power switch is reversed, and when there is 5V, it will be charged to the battery from the internal parasitic diode

Thanks to netizens for correcting, when the PMOS tube (Q2) is connected to an external voltage of 5V, it will indeed be poured back to the positive pole of the battery through the parasitic diode, and the actual adjustment will be reversed, and the source S and drain D of the PMOS tube element will be reversed, and the problem will be solved.

The schematic and PCB files have been modified, and the electronic data files have been re-uploaded.

Friends who have made plates before this time suggest that the PMOS tube components should be flipped over during the actual welding, and the positions of the No. 2 and No. 3 pins should be reversed for welding, and the problem can be solved.

We apologize for any inconvenience caused.

In terms of 3D drawings, the bearings were replaced with stainless steel optical shafts with a diameter of 2 mm, and the corresponding hole positions in the 3D drawings were also adjusted. The drive motor was replaced with an M10 planetary geared 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 (VBAT), the R5 pull-down resistor pulls the gate level of the PMOS tube low, the PMOS tube turns on, and the battery powers the system.

When the TYPE-C power supply (5V), the gate level of the PMOS tube is pulled up to 5V, the PMOS tube is cut off, and the battery stops supplying power to the system, and the 5V power supply supplies power to the system through the diode D1.

Because the VCC voltage is higher than the VBAT voltage, the battery power does not flow into the VCC through the parasitic diodes of the PMOS tube.

The PWM speed regulation function is generated by the oscillation of the NE555 time-base circuit. The frequency range can be set by setting the capacitance value of C16 and the resistance value of the adjustable resistor RP1.

The output duty cycle can be adjusted by adjusting the resistance of the adjustable resistor RP1, 1-2 and 2-3 terminals.

For music storage and playback functions, please refer to the accessory chip information.

Power amplifier circuit, Bluetooth audio module, wave sensor radar module, etc., refer to the relevant materials of the accessories.

It is recommended to refer to the following diagram for the circuit soldering sequence.

Bluetooth audio module ground (AGND1 pin), you need to fly a separate wire to the power amplifier ground (AGND pin), which can basically eliminate the current sound when Bluetooth music is played.

The spectrum lamp circuit adopts multiple feedback bandpass filtering and cooperates with the audio level indicator chip LM3915 to realize the 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 printing, recommended thickness 0.2mm)

3. Electronic data (including: related chip data, schematic diagrams, etc.)

4. BOM list.