Using a phone as a terminal via USB

[Schild0r]

Hey there,
As the title says I am looking for a way to use an android phone, which doubles as the DWC screen for my printer, as a terminal via USB.
This would be usefull if
a) the wifi module somehow shuts itself down and needs to be reset (had that happen once on my Duet3 mini in my tiny printer and only way to regain access was to wait til the print finished and then power cycle)
b) I take the printer to a new spot and want to quickly connect it to a new wifi without hooking the printer up to a PC

First of all is this possible? I mean the phone's got a USB port and the Duet has got one... So hardwarewise is it as simple as that?
If so maybe someone can give me a suggestion for an app that is a suitable terminal to communicate with the duet via USB.

[rjenkinsgb]

Try a USB on-the-go adapter to give the phone a USB A socket, and a cable to the Duet?

There are serial terminal apps for Android, eg.
https://play.google.com/store/apps/details?id=de.kai_morich.serial_usb_terminal&hl=en_GB&gl=US

[Schild0r]

@rjenkinsgb I got an OTG Adapter now and connected it to the Duet3 mini and connected my phone to the OTG adapter via USB C cable.
I tried it with your suggested app but under the USB devices it says "no devices" and I don't get a popup about a USB connection on my phone either when hooking up the USB. I made sure that both cables are able to transfer data and are not just for charging.
So I think there is something else that has to be configured. Any ideas?

[rjenkinsgb]

That could be the OTG adapter is not compatible with that exact phone, or the phone does not include drivers for the particular USB<>Serial interface in the Duet.

You could try other "slave" type devices plugged in to the OTG adapter and see if any work, to test that?

I've only ever seen ones with a normal USB "A" socket, that you could test with such as a memory stick.

[Schild0r]

@rjenkinsgb I think there was some confusion:
I have a phone (1+8Pro) with an USB C port
A standard USB A male to USB C male cable - with that I can charge my phone and transfer data
The USB OTG Adapter which is USB Micro B male to USB A female - I tested that one with another Phone (1+1) and an USB stick and that worked.

So I plugged the USB OTG Adapter with the Micro B male into the Micro B female on the duet (not into the phone but that should not matter right since it is a passive cable right?) because of space constraints.
I then plugged the USB C male into my phone and the other end of the type C cable (=USB A male) into the OTG Adapter (USB A female).

I also tried the same with the other phone (1+1) with an USB A male to USB Micro B male cable and that did not show any connected devices either.

I just read through the [dozuki] https://duet3d.dozuki.com/Guide/1.)+Getting+Connected+to+your+Duet/7?lang=en again and noticed that on a PC you have to install a driver before connecting via YAT I think that may be the culprit.
I don't think there is an android driver available...
so unless there is another idea on how to use a phone as serial terminal via USB in case the Wifi module shuts itself off (it happened again yesterday) I am out of luck because I don't have a laptop and I don't plan on putting the printer next to my PC to have a terminal from which I can restart the Wifi module.

[rjenkinsgb]

@schild0r said in Using a phone as a terminal via USB:

So I plugged the USB OTG Adapter with the Micro B male into the Micro B female on the duet (not into the phone but that should not matter right since it is a passive cable right?) because of space constraints.

That's the (or a) problem - an OTG adapter contains connections, electronics or some means of telling the phone it's now a USB master device rather than slave device. A normal cable leaves in in slave mode, like the duet.

It must be the correct adapter for the phone & connected directly to the phone for it to work.

[Schild0r]

@rjenkinsgb ah I did not know that. I thought a OTG adapter would be something like a crossover ethernet cable. And with that one it doesn't matter which device sits on either end as long as there is a crossover (and even this isn't always necessary nowadays).

I will try it then with the otg Adapter on the phone and a standard micro b cable in the duet and report back.

EDIT: works

Now I only need to find wiring that fits my space constraints