[Verified] 3.5mm audio switcher-4 inputs and 1 output

-------------------------------------------------- -------------------------------------------------- --------------------------
2023/03/20 Updated
and updated the physical demonstration video
to add newly discovered problem
titles and note corrections
-------------------------------------------------- -------------------------------------------------- -------------------------------
 
0. Introduction
There are more and more audio output devices at home (computers, ps4, ns and beyond). equipment), the original 2-in and 1-out audio switcher (bought from TaoX) can no longer meet the needs, so it is necessary to buy another one to find a solution.
Unfortunately, the price of a 4-in and 1-out switch is unacceptable.
Based on the original 2-in-1-out switcher, the design idea is drawn: no common ground, 4 gears, switching 3 circuits at the same time, physical switching, twisting or breaking to switch, fixing with a board, twisting smoothly(?). Finally, the materials were purchased and the first generation audio switcher was completed.
The above is the first version of the switcher to verify the idea, using RS26-3-4 band switch, pj313 audio socket, perforated board and electronic wire. Although it is simple, there is no broken sound and no obvious interference, which proves that this idea has no problems and is feasible.
The need has been met and that should be the end of it. So why not go a step further and make it even more perfect? You can completely draw a small PCB, ask someone to produce it, and then assemble it yourself!
Thanks to Jialichuang EDA and free board making, I drew the first PCB in my life, as well as this open source project - 3.5mm audio switcher.
 
1. Introduction
This is a simple and economical 3.5mm audio switch. The materials used are RS26 switch (3 blades and 4 levels) and matching aluminum alloy knob (a set of 3.2 yuan in total), pj-313 audio socket (5 for 2 yuan).
Adopt non-common ground design, physical switching, each channel is independent. Aluminum alloy knob, simple and easy to use. The traces are divided into two layers, the line width is 1mm, there are no vias, and the traces have been separated as much as possible.
Everything was normal in the initial sample test, and no obvious noise or interference was found during use.
 
2. Note:
"rs26-3-4" in the schematic diagram cannot be used directly. If you need to use it for other purposes, please refer to the PCB and extract it yourself.
When installing, it must correspond to the letters on the back of the switch and the silk screen on the PCB. Select "4" for the stuck point.
 
3. There is a known problem that
the speaker has a popping sound at the moment of switching: it cannot be solved. It is guessed that it is caused by the physical switch switching. Please bear with it for the sake of price.
During the switching process, the video output of the HDMI switch flashes: the reason is unknown, it may be interference caused by physical switching.
The length of the interface and switch traces should be unified: the author is not good enough, and Eda learned it by watching it. I really don’t understand how to wire it, and no problems such as interference were found during use, which may be solved in the future. It's a 5X5 board, and I don't want to use holes, so it's difficult for me to wire it.
PCB should be paved with copper: I don’t understand the role of copper paving, and the 2-in/1-out switch I purchased did not have copper paving inside, so Xiao Guicao followed suit. Anyway, there is no problem in using it. You can lay copper by yourself if needed.
4.
There is nothing to change in Zhanwang. Maybe we can build an acrylic or even aluminum alloy shell based on this board.