[Training Camp] ESP32-based multimedia knob +600422A

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Name: ESP32-based multimedia knob

Implementation function:

1. Control functions via encoder knob
2. Turn the encoder left to decrease the volume, and turn the encoder right to increase the volume.
3. One click on the encoder controls the switch, and two clicks enable music switching.
4. Turn the encoder left to turn the page up, and turn it right to turn the encoder down.
5. Connect to the computer via Bluetooth and recognize the device as a keyboard input device.

Functional circuit:

1. The minimum system to control ESP32 only requires simple power supply

2. Automatic download circuit

3. Encoder connection

4.Vibration motor

A MOS tube is used to control the vibration motor to achieve feedback when turning the knob to improve the experience.

5. Voltage stabilizing circuit

Using BL9195 chip, the voltage drop of this chip is only 300ma. When the device is powered by a 3.7V lithium battery, no additional boost circuit is required.

6.Battery charging circuit

Using TP4056 chip with charging indicator light.

7.Power supply switching circuit

A Schottky diode D2 is connected in parallel. The forward voltage drop of the Schottky diode D1 is about 0.3V, which is smaller than the body diode of the MOS tube. Before the MOS tube is fully turned on, VBAT supplies power to VOUT through Schottky diode D1, which can alleviate the problem of excessive VOUT voltage drop.

8.Power supply connection

The design separates the download interface and power supply and connects them through copper pillars, which is more beautiful and separates the power supply. When connecting to the computer for program burning, it can avoid problems such as burning the computer due to short circuit due to welding problems. It is suitable for novice welders to avoid unnecessary loss.