maybe adding 12 groups of vias, even though there are 11 charlieplexed groups will make it easier to route around the hour LEDs? this PCB is starting to look like a @welshpixie mandala
All of the test Charliewatch boards fab'ed and assembled by Aisler work perfectly (other than things that I broke, like not noticing that this MSP430 requires load caps for the crystal). For the next rev I want to squeeze the LEDs closer together to shrink the watch face a bit, which might require violating the ERC.
@th cute!
@th Nice vias! Is that manual assembly?
@th I'm pretty impressed by them being able to place the small ones at any angle around the edge; a couple of the big ones a bit skewy.
@th it looks like you're only moments away from opening the wormhole
@th this is a beautiful pcb
@th I'm pretty sure Charles Stross has something to say about designing PCBs like this
@th you need to discover the seventh chevron for it to work :D
@th can you bribe someone to x-ray it for you?
@th in the last place I worked we used to have cameras with lenses that could look under big BGAs. No idea on where might have one but I know it was $$$$.
@hughsie since I don't have an x-ray or inspection camera, my plan is to reflow and reflux the CPU to see if I can coax the solder to the right place. the symptoms are different on different boards, so I think it is a manufacturing issue (possibly caused by bad component design in my layout).
@th is it the same on all the boards ?
@th I *hate* stuff like this, where it's so obviously going to trip people up and the relevant terms in the documentation are only things you can really search for if you already know what the problem/solution is.
@th their documentation and weird errata is the #1 reason that I'm completely done with TI microcontrollers/processors.
@th This happened to me recently too. The 4-line paragraph got split in half at the page break and basically blended into the datasheet’s header and footer. I spent DAYS trying to figure out what I was doing wrong before I noticed the “here’s the unlock/lock sequence you must do for accessing certain configuration registers”.
@th I thought the version you showed me and Shenzhen a few years ago was beautiful, but you’ve outdone yourself.
@th this is so cool, and now I'm imagining it with white LEDs and a tinted acrylic cover 🤔
@pixls I made a white version of the single-color design, but the problem is that the forward voltage on the LEDs is too high, so once the battery drops below 3V it stops working. This means a few weeks instead of a several months of runtime with the red/yellow LEDs that can go down to 1.9V.
@th oh wow, wild. that does look great tho
@federico3 @pixls many of my watches are 24-hour, although the observation was that nine charlieplexed IO lines could drive 9*(9-2) = 72 = 60 + 12 LEDs. For the bicolor ones 12 IO lines can drive 12*(12-1) = 132 = 60 + 60 + 12 LEDs. There weren't any values that provided nice 24-hour dial combinations.
@th Very neat :)
For everyday use I would prefer it to make special moves only on special occasions (like end of the workday), but I assume thats presentation mode :)
@th omfg this is gorgeous! 🤩✨
@th Looks really cool✨ congrats on an interesting project!
@th @codinghorror is there no top layer on the print?
@th WOW 😱
Bi-color Charliewatches are assembled and ready for testing.