World's Greatest Headphones

This log is something I don’t do usually, which is a recovery log. My very first devpost, I ran into the issue on lookout where my video timelapse would save on lookout, but not add to hackatime, since the original recording link got closed. I was very dissapointed with this, as I’d lost my very first work session, which too was four and half hours.

Looking through the slack, it seems other people have had the same issue, and some people indicated that they solved it by playing out the screen capture on slow motion, for lookout. I implemented this, throughout this session, except for an hour of this session, the video was paused, hence the extra time. I hope this isn’t a huge issue; it wasn’t intentional.

To summaraize what the session was actually about, basically, I recreating my original component diagram, within a new project. This was because, the original, I felt, had many flaws, like for example the lack of net classes that were organized. Also, I was reconsidering the layout work of the original pcb. Mostly the work was transitioning my pcb into a new project folder.

Anyways, that is all folks…

This work session I added test points. This was something I noticed on many designs, especially for prototype boards, and I decided to implement them as well. This was tricky however, as my board is already incredibly dense, and test pads can take up considerable space.

After adding the pads, and re-updating my pcb from schematic, I noticed that all the 3d models were gone again. And worse, the custom footprint I designed for my bluetooth chip was also gone. The footprint for the bluetooth chip was especially tedious to make, as I added a bunch of zone rules like no copper fills and components, and such based on the application circuit.

This was and is frustrating, but I think the reason, was because my edits were saved to the pcb rather than to the footprint library, which meant refreshing the pcb page, lead to the changes being lost. I plan to fix this, by getting more familiar with the footprint editor, so my work doesn’t get lost.

Speaking of which, the next journal will actually be a recovery journal, as early on this project, I lost a four hour session due to a lookout recording bug. So, I plan to play out the screen recoding of the 4 hours, which has to be fair game, given how this is the SECOND time, I’ve lost a 4 hour session.

Anyways, that’s all for now folks…

In trying to redesign, this board, I’ve encountered several helpful suggestions in terms of routing and component choice. This session was spent fulfilling them.

First, for the SWD programming interface, I had initially exposed female socket headers, which were layed horizontal, and thus occupied tons of room. Instead someone suggested I use a tc2030 connector, which is significantly smaller footprint-wise, and looks pretty cool.

I also deliberated whether to use a 2 layer or 4 layer board, and after some thought, for this design I’ll be using a 4 layer board. Though a 2 layer board is easier to setup, it is harder to execute well, and certainly suffers from more pitfalls in terms of signal integrity.

Specifically, within the 4 layer stackup, I opted for signal-ground-ground-power stackup (same as last time), because I can dedicate a ground to analog and another to digital, as is common in audio applications.

Finally, I added 3d models that were missing (somehow again) for the footprints, leaving me with board setup for next work session.

That’s all for now folks….

Alrighty, this will be a pretty dense devlog, but it’s because I’ve been procastinating a lot of the work ;).

For context, the goal of this project is to develop an affordable bluetooth dac, that can also act as a standalone dac, and a bluetooth microphone. A dac or digital analog convertor is a device capable of converting digital signals to analog, which in my case is converting USB-C music to “audio jack” music. A common example is Apple’s dongle.

The point of this device is enable anyone with wired headphones to use them wirelessly. But, most people prefer wired headphones because you don’t need to charge them. So I thought why not allow them to be wireless when I need to(running, activity, etc), and turn them back to wired, when I’m sedentary, thus also charging them during wired use.

I began working on the schematic, and sourcing parts, and planning out the overall circuit around 3 weeks ago. And at this point I’ve probably spent over a hundred hours undocumented. But, better late than never, so here I am trying to catch up.

This work session was spent importing my schematic’s components into the pcb editor, where I noticed a few annoying things. Firstly, a lot of the componenets were footprints imported from EasyEDA’s library, which for some reason didn’t include access to the 3d files. I spent a good amount of time back and forth refreshing KiCad and importing the files, until they appeared adn I was able to import all of them.

Next, I was setting up the parameters of the board before I begin routing; things like layer stackup, differntial pairs, constraints, net classes. Here I found that I kept running into a problem where design rules checker complains about solder mask bridging between pads. After a bunch of research and troubleshooting, I realized I made a stupid mistake. The footprints I used for my resistors were 0201, where I meant to use 0603, wwhich meant they were all way smaller than they needed to be.

So I’ve fixed that, and now I’m deliberating a few things for the next work session. Mainly, I’m split between whether I want to use a 4 layer or 2 layer pcb for my design. A 4 layer design would simplifiy routing, and improve signal quality(and my ealier iteration was 4 layers too), but the main goal of this project from the start was affordablility, so in that regard a 2 layer board is significantly better option.

Anyways, that’s all for this log, future logs hopefully won’t be as dense. Thank you for reading :)

IMPORTANT SECTION BELOW(***for stardance admin):
Earlier today, I spent a 4 hour session(pictured below), redesigning my circuit schematic before I begin another pcb layout. I guess, there is some kind of glitch where lookout sessions aren’t connected to my project if the stardance tab is closed, while the session occurs. If any admin sees this, please comment a fix, because I’d like to claim the hours.