10/2/2025 - Did a bit of brainstorming

For the past little while, I've been simply brainstorming how this watch is going to function, particularly with the microphone. Currently, the microphone is in a pretty unfortunate spot on the PCB, and I'm not sure how well it'll pick up sound. I've thought about moving it to a separate PCB that I mount sideways in the case, to get much closer to the user's mouth, but I'm not sure how feasible it'd be. I'd have to add testing pads for soldering wires to connect the two PCBs, which may be challenging to route.

Other than that, I did some research regarding how I'd receive and send texts on the watch, and found that I can do it, but only with Android. That's OK, still. I also looked at using the microphone on the watch during calls, but since ESP32s can't act as Bluetooth microphones or speakers, it's pretty much impossible.

12/19/2025 - Redid microphone, moved some components

I'm back from the Anicept Cel :D

Anyways today I got the microphone situation figured out. I moved it to its own lil island and added two JST SH connectors to connect it all together. I plan to dremel the microphone bit off, so that JLC can treat it as a single pcb hehehe

I did a little bit of moving the components around, grouping caps with their respective chips and allat.

Proud of how it's looking! I did go over the DRC a little bit in the time I had remaining, and fixed some parts that were too close to the edge.

2/23/2026 - Finalizing and editing the pcb

For the past week ago or so, I've been sort of going over the pcb and fixing stuff, mainly the battery charger. Because the TP4056 charger that I'm using doesn't have built-in power path, I had to make one myself:

It's not really all that complicated, it turns out! And so, I moved some stuff around to fit these components in:

Also, as you can tell, I've widened the power traces. All 5V is now 0.5mm thick, and all 3.7v and 3.3v is 0.4mm thick!

I also did some work on the USB. Originally, I had three individual TVS diodes for ESD protection. Now, I'm using the USBLC6-2SC6, since it's smaller and generally like way better apparently

this was a bit of a hassle to get to fit... but I got it eventually!

but maybe the biggest thing I did in this time was create a BOM on digikey, instead of jlcpcb. I've been having a lot of problems trying to figure out the best way to order this thing, and I think i've finally decided to get just the bare pcb from jlc, and get all the components from digikey (except for that stupid $15 shipping screen :sob:). Also, for some reason, they don't carry the TP4056, so I'm going to be buying one of those modules on aliexpress/ebay, and just desoldering the tp4056 from that. I'll buy myself a hot air station + solder paste on amazon or something, so I can solder all these teeny tiny components. Anyways, I've made a cart share link here: https://www.digikey.com/short/n9zp43zq

I'm not sure whether or not I'm gonna have budget room for a stencil yet. If not, I can 3d print it with a .2 nozzle, but I'd rather have a precise machined one instead.

The total cost is looking something like $25 for the screen, $55 for the parts (yikes), $8 for the battery, and like $10 for the pcb + shipping, for a total of $98. That's not too bad! It's cheaper than LCSC because only digikey has the specific screen connector I need, so instead of paying ~$15 lcsc shipping and $7 digikey shipping, I'm only spending the digikey shipping, which makes up for the price of the parts themselves.

As I was going through the BOM, I noticed a lot of small changes I had to make. Things like the wrong LED size, wrong resistor values, etc etc. I'm glad I had to go through this, cuz otherwise it may have fried itself lol

welp that seems to be about it

this thing is really coming along and I'm excited :)

3/2/2026 4 PM - Started the case finally

alr i've been postponing this wayyyy too long

yesterday i started on the case finally. all i did really is just import all the components and move em around to get this thing:

It looks pretty fat in fusion, but it's actually sorta slim:

Looking at about 22mm width and 50mm diameter when it's all said and done. Definitely not the tiniest watch, but not too shabby. I could look for a smaller battery, but idk how much it's worth it.

I also had to shift the display port over 0.75mm (which is big numbers in pcb design) because the display cable is actually offcenter just the teeniest bit. that was annoying.

3/2/2026 5 PM - case work

in the past 1.3 hrs or so i made this goofy lookin guy

the lil raised rectangle on the side is where the mic is, and you can see its hole there too. the two knobs things that are sticking out are the buttons... not exactly sure how to do those? I may just leave the buttons themselves exposed??? i honestly might edit it to have smaller tactile switches so that i have room to make big fat 3d printed buttons instead. future me problem ig

left this hole on the bottom to accomodate battery wiring at some point.

this thing doesn't really look like a watch ngl, so i'll do some aesthetic work soon

3/6/2026 - CAD work: slimmer + nicer

the past couple of days i've been focusing on making the watch look nice, and above all making it slimmer. I've got it down to 17.5mm thick now... by no means thin, but alright i guess. It's such a fat watch 😭

here's the cross section:

i worked a lot more on routing the display cable, and settled on it sticking out of the bottom like this

i'm going to hide it with the strap, which comes out here:

as you can see, i did quite a bit of work fixing the microphone area. I'm still gonna replace those big buttons with smd ones, just haven't gotten around to it yet.

the bottom now has a press-fit connection, and of course strapping it to my wrist will keep it securely in place even if the snap fit is loose:

oki doki that seems to be it :D

3/11/2026 - CAD work - straps!

For the past couple of days, I've been focusing on the straps and how I'd like them to look. I took heavy (VERY heavy) inspiration from this model, which caught my eye when looking for other people who've 3d printed watch bands. (Dw i fully redesigned it to fit my watch size)

as you can see, i've mounted the straps to be at 45 degree angles, so that they can bend more freely downwards than if they were sticking straight out, but can be laid flat on a table, impossible if they were sticking straight down.

I love how the hexagon style balances rigidity and strength, while making it flexible and able to wrap around a tight radius. Hexagons are the bestagons! All in all this strap is a very clever design, and huge props to Lars Printing Solutions for it.

Anyways, here's how the back one connects:

I realize as im writing this that it actually intersects with the battery and is also unable to be assembled, so there's something i have to do :sob:

Well here's the front one:

This shouldn't have any issues??? Well anyways that seems to be it! piece by piece this thing is coming along :)

3/25/2026 - Removed all vias-on-pads, light cad work

today i uploaded the tempus pcb to jlc, and found a startling occurance:

that's right, via covering for my vias-in-pads is way too high. so I went through the pcb design and painstakingly moved every single via-on-pad i had off the pads, so now it's cheap!! the only thing i'm unsure about are my thermal vias, that is, the ones on the heatsink pads of some chips. I've seen sources that say I don't need to fill them, but I'm not absolutely certain yet.

I also fixed the watch mounting shenanigans and made them the same width (one was like 1.5mm thick and the other was 2.4mm thick; now they're both 2.4mm thick)

I'm still not super happy that this is the size of a 5020 fan, but at least it should work... right?

i should be able to submit soon, after i find out how on earth to do software (with claude's help... I'm not a software guy...)

3/29/2026 - Finished! Ready to submit

First I decided to remove the buzzer in favor of a vibration motor! That actually didn't take super long, as it was simpler than I'd thought, and I had room in my cad. I made a cool logo thing (now the banner for this project!) and made sure that the cad was all printable. Then I finished making the BOM, which took way too long, since I kept finding things I forgot to add to the digikey cart 😭

anyways, I then made sure that this thing follows the bp submission guidelines, exporting my step and fusion files, editing the readme somewhat, and uploading all the production stuff. I came up with this wiring diagram:

and generally made the repo look nice

alr ima submit this bad boy now. wish me luck.