Physical display

Project Description

This project mainly originated from the foreign open source project SmartKnob, on the basis of the original version, in order to be as thin as possible to adapt to my later projects, but also in order to be able to use the domestic buy motor, here redesigned the structure, hardware, and software also added a few of their favorite functions.

Demo video

I made a magic knob! FOC haptic feedback knob_Bilibili_bilibili

Project-related features

It supports all the functions of SmartKnob original, including music box, astronaut, computer volume controller, computer load monitor, SurfaceDial function, and dual-machine linkage function.

Design Principles

1. The main control selects ESP32S3, supports wireless communication, and is compatible with FOC, LVGL, etc.

2. The audio part CX800 voice chip, the main control is controlled through the serial port.

3. THE USB TYPE-C INTERFACE IS REVERSIBLE AND CORRESPONDS TO TWO FUNCTIONS, ONE IS THE DOWNLOAD CIRCUIT CH340, THE OTHER IS THE FILE SYSTEM OF CX800.

4. The motor drive is TMC6300, and it supports 1S lithium battery low-voltage platform, no need to boost the voltage.

5. The magnetic code uses AS5047P to communicate with the master through SPI.

6. The host computer and the knob are connected through the USB serial port, which supports volume control and computer load monitor.

7. Pressing haptic feedback is to use the HX711 chip with 4 strain gauges to sense pressure, and the drive motor simulates vibration after reaching the set value.

Hardware description

PCB Requirements:

1. Main control board: FR-4 plate, thickness 1.0mm, 4 layers of board, manual welding is recommended for gold immersion treatment on the surface of the pad.

2. Download audio board: plate FR-4, plate thickness 1.0mm, double-layer board.

3. Screen adapter board: plate FR-4, plate thickness 1.0mm, double-layer board.

PCB Bill of Materials:

See the attached BOM, do not refer to the schematic or PCB, be sure to refer to the BOM.

Software Description

Use vscode+platfromio development environment, including lvgl, SimpleFOC, etc.

Reference items

SmartKnob original address: https://github.com/scottbez1/smartknob

FOC Explanation Fragment: https://blog.csdn.net/K_O_R_K/article/details/123546950

Haptic principle reference: https://zhuanlan.zhihu.com/p/397682247

Open source materials

1. 3D drawings of structural design (Knob_3D.rar).

2. Hardware design schematic diagram, PCB file.

3. Adapt to the original SmartKnob source code (SmartKnob_firmware.rar) of this knob.

4. After the source code of the new function, the music box, astronaut, computer volume controller, computer load monitor (lx_knob_firmware.rar), and SurfaceDial function (lx_Surfacedial_firmware.rar) are to be updated.

5. Complete BOM, including structural parts and electronic materials (Knob_BOM.xlsx).

6. Precautions for production (knob production instructions .pdf).