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Better USB->TTL?

Aisling Lightworks
 

Hey everyone. I've been running the stm32 version for a while using the wifi connection. I'd like to start using the serial connection to see if my guiding improves a bit (latency) but this micro USB connection is just awful. They jiggle and lose connectivity. I've never been a fan of them. Can you recommend an equivalent part that has a usb-C port or just a better way to do it in general?

Khalid Baheyeldin
 

On Fri, Jan 10, 2020 at 07:32 PM, Aisling Lightworks wrote:
Hey everyone. I've been running the stm32 version for a while using the wifi connection. I'd like to start using the serial connection to see if my guiding improves a bit (latency) but this micro USB connection is just awful. They jiggle and lose connectivity. I've never been a fan of them. Can you recommend an equivalent part that has a usb-C port or just a better way to do it in general?
The connection over USB should be more stable than WiFi.
I don't know if they will improve latency or not though.

As for wiggling, I have never experienced this, on two boards.
I soldered them directly to the PCB (no female headers), all the pins, not just the needed ones, and never had any issue that way.
Are you sure it is not the USB cable connector itself that is at fault here? Try another and see if it is different.

Aisling Lightworks
 

Yeah the USB cable wiggles in the USB socket. They wear out quickly. Especially out in the elements. I've got to replace this one because it's worn out and I'd rather just switch to a much better usb-c or some other solution altogether to get rid of the micro-usb

Khalid Baheyeldin
 

On Fri, Jan 10, 2020 at 07:39 PM, Aisling Lightworks wrote:
Yeah the USB cable wiggles in the USB socket. They wear out quickly. Especially out in the elements.
Not my experience.
I have been using my controller since September 2018, and never had any issue with it.
Also, my test controller is used regularly, maybe more than the one on the mount, and no issues with USB.

There are also 260 or so STM32 users out there. If half of them use USB, then we did not here about any complaints about it.

I've got to replace this one because it's worn out and I'd rather just switch to a much better usb-c or some other solution altogether to get rid of the micro-usb
There are many styles of USB to TTL adapters on eBay.

For example this mini-USB one by FTDI.
Or this USB male one.

Get one that you like and just solder the correct pins, and you are good.

Don't see USB-C ones. Too new for the Chinese low cost manufacturer, I guess.

Aisling Lightworks
 

Okay, so any usb-ttl adapter and then just hook up the RX,tx, and ground?

Aisling Lightworks
 

And yeah, I've tried a brand new cable in it and it's still loose, maybe I just have a bad socket or maybe it got bent, for whatever reason it's no good anymore. I've always had terrible luck with micro USB, from PS3 controllers to phone chargers, they just never seem to make it longer than a year or two

Khalid Baheyeldin
 

On Fri, Jan 10, 2020 at 07:54 PM, Aisling Lightworks wrote:
Okay, so any usb-ttl adapter and then just hook up the RX,tx, and ground?
That is basically the idea. No connection for 5V or 3.3V, otherwise bad things happen.

Be careful when you desolder, since the copper may peel from the PCB, and it is then ruined.

Howard Dutton
 

On Fri, Jan 10, 2020 at 05:05 PM, Aisling Lightworks wrote:
I've always had terrible luck with micro USB, from PS3 controllers to phone chargers, they just never seem to make it longer than a year or two
My early designs used full size USB but I too moved away from it.  If I was worried about this kind of thing I'd 3D print a socket on the panel where the micro usb plug slides into it to provide strain relief.

Aisling Lightworks
 

Yeah I'm not sure exactly what I'm going to do yet. I just acquired a 3d printer and am designing some brackets for the board and motors to make a more polished install. Just trying to think of a more durable connection. 

Khalid Baheyeldin
 

If the connection is bad due to metal on metal, then I doubt 3D printed parts will help.

Maybe some soldering can help.
Check if it is wiggling where it is soldered to the module itself. Sometimes a couple of dabs of solder will do the trick.
The Blue Pill suffered from such issue, and it was always recommended that extra solder is used (see Known Issue in this link). We don't use its USB connector though, so this is a non-issue for OnStep.

If the connector on the inside is loose, I am not sure it can be salvaged.

Kevin Dorsey-Tyler <kevindt@...>
 

I have two of the STM32 kit boards, plus I built a Max2PCB, and I have used all of them almost entirely via USB connections from Raspberry Pi-based boxes.  My experience with the STM32 kits is that these little cheap USB-TTL boards work fine if reserved for occasional re-programing etc. on the workbench.  However, the micro-USB connectors fail easily if used for repeated use either where there is slight flexure from mount movement or where there is a mildly damp environment.  Both of the STM32 kits have had micro-USB connector failures in use.  The connector on the Teensy seems to be significantly less prone to failure.

I originally tried replacing the USB board, 3D-printing a strain relief and gluing it to my case to support the USB plug and zip-tying the plug onto the strain relief.  It works but isn't pretty, and they still corrode easily.  

What did work much better was to remove the USB-TTL board and replace it with another Molex connector soldered in its place.  I reworked my 3D-printed cases to allow for a DB9 serial connector to be added and connected to that header, and then I used a USB-TTL cable with DB9 output.  Those connectors are designed for repeated connection under less than ideal conditions, unlike the micro-USB.

George Cushing
 

I've look for something that would be pin compatible in vain. These are available from Alibaba.


However, the pinouts for TXD and RXD are reversed so some kind of daughter board would be needed. 

Khalid Baheyeldin
 

On Sat, Jan 11, 2020 at 10:17 AM, George Cushing wrote:
I've look for something that would be pin compatible in vain. These are available from Alibaba.

However, the pinouts for TXD and RXD are reversed so some kind of daughter board would be needed. 
I was thinking along those lines: ignore the pin order. Just solder pin headers instead of the CP2102, then
use Dupont female-female from there to the replacement module of choice. Then affix the new module
to the mount somewhere convenient, and you are done.