Sending realtime data EMG to my Android via BluetoothLE

[ChrisWard]

Hi Muhammad

The reasons why we want Forum First:

Please do not private message the Power Users directly unless invited to.
1) We are a small team collectively supporting thousands of Users
2) The person messaged could be unavailable for days or weeks and the message left unread.
3) By keeping the discussion on the forum, there are many people from all around the World (different time zones) who can potentially help you, not just the first responder, who may be unavailable. Plus, there is often something that many forum members can learn by reading the posts.

I can make an exception to the rule but I'm not available until this evening (UK time) at the earliest.......

[Muhammad_Zulkifli]

I'm so sorry sir, I didn't think that far
And because I have sent a message also to Mr. Juan Antonio, so I'll be waiting for a reply from him to be able to open a new forum or not
Once again I'm so sorry sir, if I open the forum I hope for your help again. Have a nice evening

[ChrisWard]

Hi Muhammad

What is the purpose of the data? What happens (or should happen) at the receiving end?

[Muhammad_Zulkifli]

@ChrisWard

What is the purpose of the data

There is no purpose at all sir, in my project the EMG graph is only for monitoring.

[ChrisWard]

Just a note on-the-fly: best practice is to not hide/show components like buttons - imagine if that happened on your car dashboard - totally confusing!

SCREEN1, SCREEN2 and CONTROL are buttons and should be identified as such.

So, the data for the graph should be from the Arduino Nano? The Sketch LED_COBAK6a.ino does not send anything, it only receives.

I might add at this point that there is a recent beta update of the BLE Extension to work with Android 12:

Beta version of BLE extension for Android 12 permission changes

Hello everyone, We have a beta version of the BLE extension that incorporates the new Bluetooth permissions introduced in Android 12. Please make a backup of your projects before upgrading the extension. Because this is a work in progress, there may be issues that still need to be addressed. If you try it out, please leave feedback in this thread. edu.mit.appinventor.ble-20230223-beta.aix (200.0 KB) Regards, Evan W. Patton, Ph.D. Lead Software Engineer, MIT App Inventor

I think your Clock1 timer Block is an attempt to receive data (x,y?) from the Nano?

The values should be sent together in sequence from the Nano, using one UUID Characteristic. A clock timer is not required for real-time streaming, the BLE extension has a block for that, you just have to register it first.

For example: (note, I'm not familiar with Juan's Extension)

[Muhammad_Zulkifli]

@ChrisWard

I might add at this point that there is a recent beta update of the BLE Extension to work with Android 12:

I have read about it sir, in my opinion there is no change in android 12 as said:

@Anke

I checked it on an Android 13 device. It seems that the Location sensor must be enabled (also on Android 12+) to get BLE devices (BLE.DeviceList) - Companion & APK.

@ChrisWard

For example: (note, I'm not familiar with Juan's Extension)

Honestly, me too sir. I don't understand about his post

Well, let me try my best sir

[Muhammad_Zulkifli]

I have tried sir, but on my Android display the graphics don't appear

And this is my blocks

[ChrisWard]

I think you will need Juan's advice on how to populate the graph. App Inventor has a built-in Chart component now, you might like to give that a go.

I see your values are now correctly produced in the .ino - are they being correctly sent to the App? Test by sending the values to a label in the App.

I suggest this should now become a Forum Topic.

[Muhammad_Zulkifli]

@ChrisWard

I suggest this should now become a Forum Topic.

I hope so sir, but I have asked for permission

[ChrisWard]

I have just changed the Topic status.

[Muhammad_Zulkifli]

ok sir, I hope to get a solution soon

[ChrisWard]

Couple of important things Muhammad:

1. We can't read your blocks to the right of the image and they are the ones we need to see.
   EDIT: It might help if you first used 'Clean up Blocks' to arrange them in a single column.

2. We need to see your modified .ino file

[Juan_Antonio]

@Muhammad_Zulkifli

I hope to get a solution soon

Your Arduino BLE must send a String every second, example:
245,767
282,789
...

Your App must receive that String in a Label, example:
245,767
282,789

[Muhammad_Zulkifli]

@Juan_Antonio

Your App must receive that String in a Label, example:

Do I have to activate the clock first, sir?

[ChrisWard]

You don't need a Clock in the App, just ensure that your Sketch (Loop) sends the values every second. Use elapsed milliseconds like this:

//ArduinoToApp.ino  02/03/2021 02:38:48

//Fake data stream to demo elapased milliseconds timing


//vars
unsigned long lgUpdateTime;

void setup()
{
               Serial.begin(9600);
               lgUpdateTime = millis();
}

void loop()
{
	           if(millis() - lgUpdateTime > 1000)           //Loop approx every 1 second
               {
                         lgUpdateTime = millis();

                         //Bluetooth to App
                         Serial.print("Hello");
                         Serial.print("|");      //Value delimiter
                         Serial.print("World");
                         Serial.print("|");
                         Serial.println();        //This empty last line tells App "End of Data" = Ascii LineFeed Char Number 10
               }
}

Your content is entirely different, this just shows how to use elapsed milliseconds.

[Muhammad_Zulkifli]

ACTUATOR_COBAK6a.ino (8.3 KB)
How about this one, sir?

[Muhammad_Zulkifli]

I just type println, is that not enough, sir?

[Muhammad_Zulkifli]

@Juan_Antonio

Your App must receive that String in a Label, example:

I have tried sir, but an error appears like that
and this is my blocks

[Juan_Antonio]

Don't draw, just present the data in a Label
234,765