array of Teensy solutions (e.g. for rackmount)?

b2020

Member
Trying to figure out some basics about cost, robustness, maintenance, repair in case of deploying hundreds of Teensy boards, to rack mounts.

There are two possible approaches:

a) make each node a separate Teensy + custom shield/breakout. 3d-print a box for each, or a rack mount box for many.

b) make a custom carrier PCB that has all the breakout connectors, possibly even power, for many Teensy boards (on headers)

In the second case - multiple Teensy share a single large "shield" - physical force from plug/unplug does not hit the individual Teensy boards, defective Teensy boards can be swapped on the headers, all the breakout connectors - RJ45, USB - can be multi-port jacks and, parts permitting, can even be screw-secured to a single custom faceplate instead of just soldered. Sounds like a win?

Has anybody done something like that, say for an LED installation?

The spoiler is the Teensy on-board micro-USB.
I have to use that port, and need access to it.
There are test pads, but there is really no way to route it to pins / to a header?

I could try something like plugging a micro USB male breakout into every Teensy, and then putting both Teensy and micro USB breakout as a unit into properly arranged headers, to route to faceplate sockets from there.

Or I'll just mount the Teensy boards side-by-side on the carrier PCB along the edge, micro-USB facing forward.
That makes it a PCB N Teensy wide and barely one Teensy-plus deep.
Or two Teensy-plus deep if I use the opposing edge as well, might be crap in a rackmount.

Any existing project references, parts suggestions, alternatives?
 
The USB test pads can be routed to a header. The Teensy 4.0 doesn't have those pads but it should work on the others. The T4.1 has components on the bottom so it won't sit flat on a board for castellated-type solder connections, so you're likely to need pogo pins or some other spring-loaded solution.

"Hundreds" sounds like a maintenance nightmare to update firmware. Make one change and spend 2 hours plugging a USB cable and hitting "upload"? That's where you really want to rout them to a USB hub and then you've got one cable to plug in for 8 or more Teensies.

Look into "eurocard" or other backplane type solutions. You could solder 4 or more Teensies onto a card that plugs into the backplane.
 
The USB test pads can be routed to a header. The Teensy 4.0 doesn't have those pads but it should work on the others. The T4.1 has components on the bottom so it won't sit flat on a board for castellated-type solder connections, so you're likely to need pogo pins or some other spring-loaded solution.

Yeah, I wasn't expecting castellated solder. Not cutting Teensy edges like some have tried?
I already accepted headers so that dead Teensy can be swapped.
https://forum.pjrc.com/threads/28847-Request-Castellated-Edges-on-Teensy-3-1-PCB

"Hundreds" sounds like a maintenance nightmare to update firmware. Make one change and spend 2 hours plugging a USB cable and hitting "upload"?

Indeed.

Each Teensy will be connected to a host as a USB HID device, so in theory I can try to port the bootloader CLI to the target OS, and have them upload the sketches from a single server source.
https://www.pjrc.com/teensy/loader_cli.html


My real problem is that that requires me to use the existing micro USB, because I take it I cannot make the Teensy look to a different serial:
https://forum.pjrc.com/threads/41751-Is-the-Teensy-boot-loader-source-available

I need a single Teensy to connect to two hosts, as two separate devices - one, as a Teensy VID/PID to PC host for development, the other pretending to be a (composite) USD HID device with a different VID/PID.

I had that garbled here with the need for Teensy being host to multiple devices, which can be solved with a DIY HUB
https://forum.pjrc.com/threads/60906-Teensy-4-1-how-many-USB-ports-w-o-hub

But I have yet to find a solution to get another USB HID device connection - UART-to-serial-USB, yes, but not HID/Raw HID.



Look into "eurocard" or other backplane type solutions. You could solder 4 or more Teensies onto a card that plugs into the backplane.

Thanks!
I can probably put a hub on a PCB for 4 or 8 Teensies as well. Once I have the problem of being two things to two hosts solved.....
 
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