Solder to D+/- test points in commercial product?

D

Dazzer1234567

Member
Hi folks,

Despite being a total noob with electronics / coding / Teensy etc, I'm planning to turn my first Teensy project into a commercial product.

I'm making a DAW controller (mated to a custom, bespoke DAW), that will need to be connected via a USB cable to a computer, and which will also need to be slightly portable, in the sense that people should be able to move it around a desk or whatever.

So for this application, the onboard micro USB connector on the Teensy 4.1 just isn't going to cut it, because in my experience it's not a reliable connector, mechanically speaking.

So I'm looking to place a connector on the side of the case. At the moment i'm thinking about a 4 pin XLR (tying the shield & ground together), although I'm open to suggestions for something else.

And then internally, i have the choice to either use the micro USB connector on the Teensy, or to solder my connector to the D+/- test points (and solder 5v and ground to the pins).

Which brings me to my question: is it wise, in a commercial product, to use these test points.for the D+/- USB connection? The alternative (using the onboard USB connector) also seems less than ideal, considering the possibility of intermittent connection or it working loose during tranport.

Any guidance or words of wisdom or advice would be appreciated!
 
As a user, I don't think I'd like powering a commercial product via XLR. Plugging in the wrong cable over the wrong port could potentially cause some damage, I think?

I built a MIDI controller a few years ago and I used micro USB to USB C panel mount adapter which has held up well. From the outside it looks like a normal USB C port and the Teensy doesn't move around inside so the weaker micro USB connection remains secure.

Btw, it should be possible to use both a standard power jack as well as USB if you're careful. There's some info on how to do it at: https://www.pjrc.com/store/teensy41.html#power. My understanding is that if you go this route then you'll want to use some diodes to protect your circuit.
 
That's worth thinking about. Maybe i can find a more exotic connector to mitigate that risk. Maybe I'll take a look at GX16-4.

Isn't this a little bit of a weak point of the Teensy? I mean, it lacks a really robust way to connect to your computer. Micro USB sucks, and the little pads aren't the greatest for soldering to.
 
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One of the test pads has delaminatated, so indeed that seems like a bad idea.

I'm going to make a cable restraint and try to just use a short micro USB connector to a breakout plug on the case.

But I still contend that this is a shortcoming of the Teensy 4.1, and i would like to see a more rugged variant that thinks about people using them tethered to a PC in more challenging environments.
 
For what it's worth my plan for my current build is to use a panel mount USB C:
www.adafruit.com

USB Type C Screw Panel Mount to 6 pin JST PH Cable

This panel mount cable is great for making USB Type C connections with a panel-mount setup. On the small panel-mount side you get a USB C connector, the other end has power, ground, D+ / D-, ...
www.adafruit.com www.adafruit.com

and wire it up to this micro usb plug internally:
www.adafruit.com

USB DIY Slim Connector Shell - MicroB Plug

Make your own USB connections without slicing apart a USB cable and soldering those thin wires inside. This is the 'slim' version of the DIY MicroB Male connector. It's a little ...
www.adafruit.com www.adafruit.com

That way I can make the connection wire as short as possible. I don't expect a lot of shuffling around inside the enclosure so it should be secure(ish).
 
Did you considered to switch to the micromod form-factor? You just route the d+/d- from there and place whatever usb type connector you like cleanly
 
One solution we have used is to hack the libraries and configure the USB host port to instead be a second USB device. That then made for an easy connection to a nice solid PCB mounted socket. This had the added advantage (for us, maybe not for your application) of not exposing the Teensy upload port to the outside world.
 
AndyA said:
One solution we have used is to hack the libraries and configure the USB host port to instead be a second USB device. That then made for an easy connection to a nice solid PCB mounted socket. This had the added advantage (for us, maybe not for your application) of not exposing the Teensy upload port to the outside world.
Click to expand...
Ah-ha, pray tell more, Claude Code told me that wasn't possible! Do you have any pointers how to achieve that?
 
It certainly got interesting but from a hardware perspective on the processor the two ports are identical so it is possible. It's mainly a case of working around the assumptions in the teensy libraries.

The final implimentation is mixed in with our product code which I can't share but I know I did a stand alone proof of concept first, I'll have a dig around and see if I can find something.
 
AndyA said:
It certainly got interesting but from a hardware perspective on the processor the two ports are identical so it is possible. It's mainly a case of working around the assumptions in the teensy libraries.

The final implimentation is mixed in with our product code which I can't share but I know I did a stand alone proof of concept first, I'll have a dig around and see if I can find something.
Click to expand...
no worries, if you could give me some general pointers, i'm sure i can work out the rest!
 
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