Just one line, and one pixel's red channel died, but these colors 😍
PCB came out golden on the first try 🤩
Had some issues with the via drills (firstly didn't drill deep enough, then broke a drill on the press fixing it) but everything worked out.
After figuring out the issue yesterday, finally managed to mill out a keyboard shell exactly as planned today :)
I also recorded the whole thing, this time without battery issues, so hopefully I'll get an actual video out about this eventually!
V2 on the way :)
There is a 12V that has a side output, and the fake battery for the camera has 8.2V on a barrel jack. That's enough to run this fan at a decent speed, so I whipped up this CAD model, should be done printing in about 20 minutes... Let's see how many of the measurements I got right 😉
Me and my instructor glossed over the issue multiple times: It may look like this fixture fully constrains the part, but it can actually slide along one of the hexagonal parts axis. When I put the part in it was always so tight that it didn't occur to me that it might be misaligned!
I've been chasing this CNC "bug" for over a week where all the operations on the back of the keyboard were offset a little way and I couldn't figure out why. I double, triple, quadruple-checked everything in software, checked the CNC files did the right thing in a dry-run, all perfect.
Here's a picture of the part and the fixture that holds it while I'm milling the back side, can you spot the problem?
Here's a comparison between the factory-fabbed board with wrong FFC connector pitcth (my bad, top), the laser-cutter-exposed chemically etched board (bottom) and the CNC-milled breakout (right). The breakout board is as close as I could get with a V-bit and it might actually work, but its so questionable that I don't want to try it with my only OLED display.
I didn't think to drill out the via-holes in this same step, which was a mistake, so I had to do that by hand on the drill press.
Next, these little copper rivets (0.8mm outer diameter) can be inserted and punched flat on the other side. I'm using a single-sided PCB, so I'll just solder jumpers where a double-sided PCB would have traces on the other side here.
Now I still needed to route out the slot for the FFC cable to pass through. I drilled out the two screw-holes marked by etching on the drill press, and had the CNC mill pilot-drill two holes with the same spacing in a sacrifical piece of wood.
This way I could screw the PCB into place exactly with respect to the CNC's coordinate system and mill out the slot and contour (5x speed also):
Now the PCB can be rinsed with water (in another container, since the Acid remains can't just be flushed) and then the remaining paint can be taken off with a solvent.
Success! The tricky parts at 0.6mm pitch came out perfect, and there is just two little bridges that were easily fixed with a scalpel blade.
tinkering between hard- and software, research and development, audio- and visual...
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