How do I read input from an Xbox One Bluetooth Controller?

Hello,

I am writing a script that should control a Turtlebot 3 Burger via Bluetooth Controller through Matlab.

I have configured matlab and the turtlebots to communicate with one another, and I can send commands to the turtlebot to move around, read data, ect. The next part I have to figure out is how to read specific inputs from my blueooth controller.

I have connected my controller to my PC successfully, and can even recognize it in matlab using:

instrhwinfo('Bluetooth');

My question now is, I want to read inputs from the different joysticks, buttons, triggers, ect.

I want to use these inputs to create IF STATEMENTS to move the robot around.

What I have in mind is something like this:

tic
while toc<60
    
    %Use Left joystick to move bot forward
    if (leftJoystick.POS >= 1)
    velocity_msg.Linear.X = 0.100;
    send(velocity_pub, velocity_msg);
    end
    
    %Use Right joystick to turn bot
    if (rightJoystick.POS >= 1)
    velocity_msg.Angular.Z = 0.100;
    send(velocity_pub, velocity_msg);
    end
    
    %Use Left Joystick and Right Trigger to increase forward velocity
    if (leftJoystick.POS >= 1 && trigger.Right == true)
    velocity_msg.Linear.X = velocity_msg.Linear.X + 0.005;
    send(velocity_pub, velocity_msg);
    end
    
    %Use Right Joystick and Right Trigger to increase forward velocity
    if (rightJoystick.POS >= 1 && trigger.Right == true)
    velocity_msg.Angular.Z = velocity_msg.Angular.Z + 0.005;
    send(velocity_pub, velocity_msg);
    end
    
    %Use Button A to stop robot.
    if (button.A == true)               
    velocity_msg.Angular.Z = 0.0;
    velocity_msg.Linear.X = 0.0;
    send(velocity_pub, velocity_msg);
    end
    
end

I'm definitely using the wrong variables, but its just the idea of how I want to structure my code to control the turtlebot.

Does anyone have any experience with this? I'm guessing someone has implemented this before, however, everywhere I look online, I only see things using USB connections. I want to control this using bluetooth so I can follow the robot around!

UPDATE: I did some reading here: https://www.mathworks.com/help/instrument/bluetooth.html

But when I use

fopen(b)

I get this error.

Error using icinterface/fopen (line 83)
Unsuccessful open: Cannot connect to the device. Possible reasons are another application 
is connected or the device is not available.

Error in testing2 (line 4)
fopen(myDevice);

[Walter Roberson]

https://core-electronics.com.au/tutorials/using-usb-and-bluetooth-controllers-with-python.html gives some information about how Bluetooth controller messages are structured and how they can be decoded in Python.

[Previn Savaya]

Thanks for this, I'll give it a good read because it looks like some information I may be able to use down the road, for now, however, I still need this to work on Matlab.

[Walter Roberson]

delete(instrfind('Bluetooth'))

might help, possibly... but not if some other process is using the device.

[Previn Savaya]

delete(instrfind('Bluetooth'))
Error using instrfind (line 57)
Invalid param-value pairs specified.

[Walter Roberson]

https://www.mathworks.com/help/instrument/troubleshooting-bluetooth-interface.html

[Previn Savaya]

I already followed these steps.

At the step where I use

fopen(bt)

I do get an error.

The link you provided even says:

"If you do not get an error, the connection was made successfully. If you do get an error, follow the steps in the error message and/or check the previous steps listed here."

I'm assuming this error is a common one. There are no steps to follow in the error message, and I did re-check the steps provided. Very strange!

[Walter Roberson]

http://www.imatest.com/2017/01/how-to-determine-what-processes-are-using-a-device/

[Previn Savaya]

I did everything it said to do and it shows that 0 processes are using the device.

[Walter Roberson]

Then the device is not available.

You might want to use a more specific call, indicating exactly which device you want to connect to, in case it is selecting a different device.