@kl3m3n That was quick! Yes, your code which restarts the advertising in the onDisconnect routine is much better. I believe I tried putting it there first but I don't think it would compile ("not in scope" error). Then I checked out that Kolban demo and just did it his way.
You must be a pretty good programmer to be handling all aspects of this by yourself. Even programmers that do both MCU programming and either smartphone or PC applications, are often not good writers- i.e. their documentation is poor. Your's is excellent.
FYI. I have used an IOS app called TechBasic which is something like GUI-O in that it lets you communicate with MCUs via Bluetooth. It is, however, a Basic interpreter running on the IOS device. So, its a bit more versatile but you do the actual programming/development on the IOS device itself. That's not ideal. The TechBasic app itself starts up like a PC IDE for Basic programming, and you can compose/edit or select & run your Basic programs from there.. So, it's not really a stand-alone app that a non-programmer can use easily. The auto-connect feature of GUI-O is quite superior in this respect.
Also, as far as I know, IOS only works in the BLE mode- not the legacy Bluetooth SPP mode. I happen to like that the Android OS lets you use legacy Bluettoth/SPP.
So, I agree- you are right to be hesitant about an IOS app. There would be a lot of adaptation you would likely have to do.
Again- thanks for your attention and efforts on my forum posts.😊

Hie @kl3m3n
Thank you

I know, I've googled it.
The Autostart option I haven't found on my phones yet, but I'll keep looking because that could solve the issue.
Yesterday I tried to open Gui-O when the index was at 121, and I found that the App had frozen, but I was still getting the notifications from your script.
I'll turn on logcat and send it to you later, maybe you can see something that will help.

Best regards

@kl3m3n

Thank You.
I will look what for me is the best way. If need help with this, i give feedback

BR

@kl3m3n,

Have updated to 1.0.7.1 the Samsung Android 10 and it no changed the Application UUID
Good!

Don't know why my cellphone Android 12 have changed the UUID on update
Next version update i will look if it happens again

Regards

@kl3m3n ,

Thank You

Regards

Hi @kl3m3n,

Fantastic!
I already updated by Google Play the new version. When you have some example code, please send it, I can start testing on my microcontroller.

Thanks. Great feature from Gui-O

With best regards

Hi Kl3m3n,

This works, only the IP without the SCI and VIS

mqttClient.publish(&In[0], "@im8 IP:"https://i.imgur.com/vFexxxx.png"\r\n");

Solved
Thanks

Hi @kl3m3n,

I will leave it for later when I can experience a practical example.
If justified, I will return to the subject.

Thank you
Best regards

Hello @kl3m3n,

Tested, works well

Thanks
Best regards

Hello @kl3m3n,

I understand, thank you

Best regards

Hello @kl3m3n

This works and is simpler. You are the best!

String str = "@ni1 VAL:" + String(val) + "\n\r";
mqttClient.publish(&In[0], &str[0]);

Best regards

@kl3m3n

Thank you.

Best regards

Hello @kl3m3n,

Like you say, implementing a control for language selection from the GUI-O app side, which is then stored in EEPROM of the microcontroller, is a good choice.

Regards

@kl3m3n drop down box looks to be easier to use than the spinnable list.
grid of buttons also seems to work much faster than drawing each button individually. Just need to fine tune the size of each button and the colours, but I can set each button in the pattern initially, and also set individual buttons interactively.

I'll also have to see if I can load my settings from a CSV file, so that I think might be the last thing to test out, but looking very feasible at the moment to complete what I wanted to do.