LOL! I just noticed that on the screenprint (cue sample of an English mad scientist from the 40s saying “What the devil?!”).
Regardless, it works beautifully with norns, even plugged in directly. Now I need a case, and a clue on how to make it do with Windows 
P.S. What kind of test(s) would I do to determine whether or not the breakout is necessary?
Turn all the leds on full brightness and see if they brown-out/glitch. I have been testing that from the test-grid maxpat
Probably installing serialosc
Sorry, should’ve been less flippant/more informative. I have the latest serialosc installed (never had one installed before); I have Bonjour installed (for other reasons), but I understand it’s not required any more? Regardless, I get absolutely not a peep from any Max patch, in Max or in Live. Running the serialosc-* manually from a terminal gets me nothing… There’s no lsusb or what have you on Windows, so I’m kind of lost as to how to proceed.
I have spent hours trying to get it working on windows 10. Serialosc hasn’t been updated in a while, maybe it isn’t working with the latest win10. My grid shows up as serial COM3, not as a USB device with a name.
Mine as well, when running the arduino IDE thingy, but it shows up as COM4 when seriaosc is running.
This persists after a reboot, without the arduino IDE running, and oddly, Windows Device Manager shows no COM3, but if I try to customize the Teensy port, Windows shows that COM3 is in use.
Either way, I’m pretty sure that it’s not going to show up as a USB device - that’s what serialoscd is for.
This help?
Nah, unfortunately. AFAICT, the latest Win serialosc fixes all of those issues.
Having said that, I do need to check what happens if I run serialoscd manually with the grid already connected.
@okyeron; What’s the difference between neotrellis-128-10-cut.ai and neotrellis-128-8.ai?
I may end up modding one of those and getting it fabbed by Ponoko, as it seems like the Teensy 4 doesn’t need the USB passthrough (and thus the extra space in the case).
Version 8 there would be better if you want to omit the usb passthru - but the under-pcb layer could prob use some changes to better support the teensy.
This one might be better for you for that under-pcb layer (except it does not have the hex standoff cutouts - so you could hybrid-ize between the two maybe?)
neotrellis-128-5.ai (315.2 KB)
Nice, thanks! Yeah, I’m pretty adept with Illustrator, so I can Frankenstein something together without too much trouble.
actually the one I have in the repo for ponoko might be kinda what you want. neotrellis-128-old-ponoko.eps
Also need to do some additional tweaks to make sure all my layers are lining up right - last one I cut seemed off a bit in a couple spots
There was some talk earlier in the thread regarding DIYing the Trellis boards, and I ran in to this article yesterday that might put that closer to an option:
And digging a little further I found this:
I have a handful of bare neotrellis boards so yeah - interesting. Would need to test if these fit on the same footprint
Hassle #2 with making your own is programming the samd09 seesaw chip. I need to make a jig for this if I do more
@okyeron; OK, now that I’m looking at this with my “3D Designer” hat on - I don’t see where #5 goes in the stack, or what its exact purpose is (I get that it’s a spacer, but…).
Derp. Presumably, it must be 3rd down from the top, to accommodate the thickness of the PCBs
EDIT (so I’m not the only one adding posts):
@okyeron; Well, I’ll be… https://make.ponoko.com/materials/black-eva-foam . Only availble in 2 and 6mm, but…
It goes around the pcb and buttons -same plane as the pcb (1.6mm) and button silicone (not sure what the specific thickness is, but around 1mm)
Sad panda.
Preliminary testing with @szymon_k’s node-serialoscd[1] indicates “yay, it works”, but also “all LEDs on” causes the device to disconnect - I’m guessing it’s a power droop (all of the LEDs dim at once).
This is doubly hard as there doesn’t seem to be a way to connect the Teensy 4’s micro USB port’s data lines to… anything, really.
So, short of using one cable for power, and one for data (which of course means trying to dig up a data-only USB cable… is there such a thing?)…
[1] monome’s serialoscd will not work on Windows 10 with this device for me 
Offworld power splitter to separate power and data. I made a few of these recently.
Or… you can do the same by using the usb breakout and just connecting 5v and GND on the breakout to the teensy - then cutting the teesny VUSB trace and using the teensy for data only.
Would this end up being two connectors on the device side?
Two separate cables?
With the offworld, you’d just have the one usb connector on device with 2 separate cables going to the offworld.
So with a breakout instead - yeah 2 separate cables.
Which pin have you connected from the teensy to the trellis for power? I ask because I’m using a teensy 3.6 and I haven’t run into power issues even with all the LEDs on. In my case I used the VUSB pin. On the teensy 3.5 and higher this pin is before the current limiting fuse, whereas on the older teensy’s it is after the fuse. If you used one of the 3.3v pins that might be your problem…