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The PCB Goes In

A project log for Global View

Persistence of vision is awesome

JarrettJarrett 11/18/2018 at 02:460 Comments

Oh yes. Exciting.

Notice that the batteries work fine, too! I was genuinely worried that they wouldn't be able to handle the current.

Only one side, the blue side (also the Best side) has been assembled on the PCB. There's going to be one more revision for sure, so this is totally fine for testing without putting more work in than necessary.

Here is the last log (from almost a year ago!) that shows the mechanical design. Nothing has changed on that front, and I haven't implemented the changes I discussed.

Those black acrylic pieces that couple the PCB to the shafts needed to be laser cut again, because of the slight difference in thickness between the acrylic mock-up and the real PCB.

So I did that, and there was a problem that I kinda foresaw, but decided to cross it when I got to it. When the circles are full length, they can't make it past those surfacemount LEDs. This time, I just sliced off a corner, but that might not be a great idea when I have LEDs on both sides. It'll be a very weak coupler. Maybe metal or even wood might be viable, anything is stronger than acrylic. Alternatively, I could add a circular cutout in the next PCB to allow inserting the couplers sideways, then rotating in situ.

Either way, this works, just barely.

The microcontroller is mounted suuuuper close to where the coupler has to come across. I don't remember if I intentionally considered that in my design when I originally did the PCB, but it still makes me uncomfortable! Also, the spare GPIO are covered up, although my initial debugging stage is done, probably.

You can see where I soldered some copper braid around the edge of the PCB for battery contacts. I'm actually not too unhappy with that. On the other side, I soldered a spring intended for battery holders. The force on the spring is too high at the moment, though. While trying to load batteries into the holder for the first time, I let go and one of them shot across the building at (pretty sure) mach 1, never to be found again.

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