USB 2.0 HUB based on SL2.1A

PDF_USB-Hub_SL2.1A.zip

Altium_USB-Hub_SL2.1A.zip

PADS_USB-Hub_SL2.1A.zip

BOM_USB-Hub_SL2.1A.xlsx

94831

Desktop Screen V3

The PCB for this project is based on the desktop small screen PCB of the open course on the Internet by senior student Xiaozhi. The software is fully adapted, the mechanical shell remains unchanged, and the size of the board remains unchanged.

I. Project Introduction:
This project was inspired by the open-source project released by "Xiao Zhi Xue Chang" on various platforms. The main control chip and its internal software are the same as Xiao Zhi Xue Chang's. (Bilibili link: DS2-Learning Suggestions & Tool Preparation_Bilibili_bilibili).
To obtain the software, simply visit the provided Bilibili link. The project's casing, screen, and battery are identical to the original. I found compatible casings and batteries for Xiao Zhi Xue Chang's small screen by searching for "desktop small screen" on Taobao.
Note that an internet connection is required after burning the code for real-time time and weather updates. There are tutorials on this on Bilibili. It's important to note that a router or mobile hotspot is required for connection. If using a mobile hotspot, you'll need two phones: one connected to the small screen's Wi-Fi, and the other connected to the small screen's Wi-Fi.
II. Actual Usage of this PCB :
I originally planned to build this a year and a half ago, but various reasons delayed it. I didn't have time to compile the code slowly; I simply used burning software to burn the bin file provided by "Xiao Zhi Xue Chang" to run it.
The hardware PCB has been running smoothly in my hands so far without any failures. The only drawback is that the corners and USB port area don't quite fit the small screen casing, possibly requiring some trimming of the casing or PCB.
 
III. Hardware Circuit Changes
First, let's discuss the reasons for the changes. The main reason is that these are the only chips available, and I wanted to minimize expenses, especially since these chips are relatively inexpensive.
1. Voltage Regulator Chip: Changed to ME6111. Similar performance parameters to the original chip, but with a smaller package.
2. Serial Port Chip: Changed to CH304X, with a smaller package
. 3. USB: Changed to Micro USB for wider compatibility, with a larger package than the original. In fact, this larger USB port caused a misalignment between the PCB and the screen casing size at the USB port. My first version forgot to consider this, resulting in a gap in the casing at the USB port. However, in this open-source version, I've tried to make the USB port fit the casing size as closely as possible; it might only require trimming a small corner with pliers.
4. Freewheeling/Zen Regulator Diode: Replaced with MBR0540, with similar parameters and a similar package size to the original diode. It has been tested and works.
5. Other modifications:
      a. Reverse current protection for the serial port chip's RX and TX pins and the ESP32 main control chip's RX and TX pins was removed (the original design may have been for stability considerations, but I don't think it's necessary for personal use).
     b. The large pad connecting to the power chip's power interface was removed, leaving only the 1.25mm pitch terminals and their pads.
     c. The NPN transistor was replaced with a transistor commonly used in JLCPCB's library.
     d. The ground pads of the two terminal interfaces of the e-ink screen were enlarged for easier soldering and fixing.
 
VIII. Physical Display
 

PDF_Desktop Screen V3.zip

Altium Desktop Screen V3.zip

PADS_Desktop Screen V3.zip

BOM_Desktop Screen V3.xlsx

94832

electronic