04/22/2021 at 19:22 •
The boards arrived a couple of weeks ago from JLCPCB. I fired off an order to DigiKey for the dome buttons...had those a few days later. I stuck some buttons onto a board with some tape, and then tried dfu-programmer to see if I might get away with just plugging into a USB port to do the initial setup...no dice. Good thing I brought the ISP interface out to some pads on the bottom. The snag there was that just sticking some bits of header onto the business end of a USBasp was insufficient to make good contact. Looks like I'll need some sort of pogo-pin adapter to program the boards.
I found this 2x3 pogo-pin adapter that turns out to be perfect for the job. Orient it properly, push down for good contact, and fire up avrdude. With the software image, at least a minimal EEPROM image (twenty nulls), and the fuse bits set right, everything fired up. The serial configuration interface allowed me to paste in some passwords, which would then get sent on pressing the appropriate button.
I knocked together a case design in OpenSCAD and printed it out...good fit, but 1 mm thickness is probably not quite enough for durability, and I forgot to include a keychain loop. I've parameterized the case thickness so I can dial it in wherever I need it...will try 2 mm next, but first I need to replace the part-cooler blower on the AM8 in my office, as the one in there now has crapped out.
03/26/2021 at 14:56 •
10 mostly-assembled boards for $52, shipped. Used to be you'd spend more than that just on the boards.
("Mostly-assembled" because JLCPCB doesn't have the button domes the design uses. I could've reworked it for smaller ones that they do have, but since they only need to be held in place with some tape, it'll be just as easy to order the right parts from DigiKey and put them on the boards when they arrive.)
03/22/2021 at 06:27 •
...and this might be the first time I farm out assembly instead of getting some quality time with the rework station. It's not a particularly complex board by any stretch, but perhaps that's the type of board that's better for a first outside-assembly project. Sending a zipfile of gerbers is nothing new, but passing along the BOM and the parts-placement info for a pick-and-place machine will be something new.
Still need to panelize the gerbers, though, and the script I use for that is missing its dependencies because KiCad was last built against Python 3.8, not 3.9. It's rebuilding as I write this...already most of the way done, too. Throw a Ryzen 7 3800X and 64 GB of RAM at Gentoo and it'll rebuild code in a hurry. :)