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A project log for μ3D: RatRig V-Core 3 EVA wiring over RJ45

A daughter board that mounts on a 3D printer hotend assembly to enable all wiring over RJ45

Alexander WilliamsAlexander Williams 10/24/2021 at 13:400 Comments

In the previous log entry, I mentioned extending the board from 80mm to 96mm. To be honest, I hated that idea because it's just too long and didn't look very nice.

After some messing around in KiCad, I decided to bring the width back down to the original 80mm.

I moved two JST-VH connectors back up top and moved the RJ-45 connectors towards the edges of the PCB. I also removed two of the M3 mounting holes because they weren't really necessary.

This design tucks the smaller JST-XH connectors between the larger JST-VH connectors, but there should be enough spacing for them to still be accessible once cables are connected.

The one unfortunate downside of this design is I had to reroute all the existing traces. Now the RJ45 pin assignments are completely different for every connector, however it might only be necessary to re-do the wiring assembly for the ADXL: it's the only connector whose pairs don't lineup like the v.1 PCB (comparing v1 and v2 boards will make that very clear). The other connector/wiring assemblies should work just fine without changes, unless you're doing something esoteric then it's probably best to follow the new pin assignments.

Anyways, I'm quite satisfied with this design so far. All the issues from the previous v.2 batch are fixed without altering the dimensions of the board.

This week I'll perform some thermal tests on the 3mm traces for the latest PCBs. Depending on those results, I hope to ship this v.2 board to production by mid-week.

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