Hi, I have a question regarding this project. I am trying to adapt your code for Arduino to be used on an STM32 (STM32H750XB) board with MPU6050.

Will this driver work as long as the STM32 board is communicating through USB COM with a baud rate of 115200? As I am writing my own code to transmit the signal to the PC, what should be the output from the STM32 to the PC?

Hello and thanks for developing this driver!
Let me describe my problem.
I am using a homemade Arduino-based HMD device and I am faced with the problem of tracking head tilts to the right and left. The problem is incorrect display of head rotation during head rotation inside SteamVR Home (driver version 1.3 and SteamVR Version 1.24.7).
According to the results of the sketch, it looks good in symbolic form.

And translated into binary form

In SteamVR Home, while I'm standing in front of the screen, head tilts to the left and right are tracked correctly.

And the chin tilts also look correct

But if you turn your head to the right or left (yaw), and then tilt your head to the right (roll) looks like lowering your chin down (we have pitch instead of roll).

If you turn your head to the left, the same situation is observed. Tilting the head to the left becomes lowering the chin.

Turning the head back causes an inversion of the tilt of the head. For example, if the head is tilted to the right, the result is also a tilt, but only in the opposite direction.

It looks as if the coordinate system of head declaration does not rotate with HMD by yaw coordinate.
Please comment have you had any similar problems? And what could be the problem in your opinion?

Hello r57zone, I want to thank you for all the content you have about OpenVR, I am using your drivers to be able to use my modified viewer @ 135ºFOV, you can see the MOD from this website.

https://www.realovirtual.com/foro/topic/51245/mod-visor-vr-los-90o-fov-135o-fov-anonymous-vr

I had the challenge of rotating the screens in SteamVR, after doing the MOD my tilted screens projected the crossed images, "as if cross-eyed".

I have used its controller and with the "GetProjectionRaw" function, I have managed to modify the images of the screens independently for each eye.

The viewer that I am using has a 3DOF IMU per USB HID port, it sends up to 32 data in 8 bits with values ​​from 0 to 255.

I don't have enough knowledge to create a USB HID connection with your controller, maybe you can help me on this, you have programming experience.

I'm also thinking of using its COM_PORT connection to the Arduino and sending the data from the USB HID.

How are you sending the data from the Arduino through the COM_PORT?

Can you give me an example of the data and its order of sending to the driver? I understand that you send 3 data from the IMU, I have up to 32 to send, but really many are for the accelerometers, but if I have up to 10 different data that I can use for head movements, some data is in degrees and other data is raw, the IMU controller, it gives different data for the same movement.

Thanks for your attention.

I use DIY Arduino headtracker that produces the following data at 115200 BaudRate.

 float mypr[3] = {0, 0, 0}; //yaw, pitch, roll                 
            mypr[0] = ypr[0] * 180/M_PI;
            mypr[1] = ypr[1] * 180/M_PI;
            mypr[2] = ypr[2] * 180/M_PI;
           
            Serial.write((byte*) mypr, sizeof(mypr)); 

I've copied "arduinohmd" folder to SteamVR drivers folder, set COM port number in "arduinohmd" settings file. Then I've connected tracker via USB 2.0 and open SteamVR

SteamVR freezes and closes on startup every time.

The message from Windows Application log (I use OS Windows 10 ver. 20H2, OS build 19042.):

Faulting application name: vrstartup.exe, version: 1.18.7.0, time stamp: 0x60e61656
Faulting module name: ucrtbase.dll, version: 10.0.19041.789, time stamp: 0x82dc99a2
Exception code: 0xc0000409
Fault offset: 0x0009eddb
Faulting process id: 0x30a0
Faulting application start time: 0x01d783c1476f445d
Faulting application path: C:\Program Files (x86)\Steam\steamapps\common\SteamVR\bin\win32\vrstartup.exe
Faulting module path: C:\WINDOWS\System32\ucrtbase.dll
Report Id: 36913a40-0d5f-4d17-be45-d42ebb7f07fc
Faulting package full name:
Faulting package-relative application ID:

My steamvr.vrsettings file is

{
   "DesktopUI" : {
      "pairing" : "568,271,800,600,0",
      "settings_desktop" : "624,432,800,600,0"
   },
   "dashboard" : {
      "enableDashboard" : false
   },
   "steamvr" : {
      "activateMultipleDrivers" : true,
      "allowAsyncReprojection" : false,
      "directMode" : false,
      "enableHomeApp" : false,
      "installID" : "13246197459664423944",
      "lastVersionNotice" : "1.18.7",
      "lastVersionNoticeDate" : "1626220647",
      "showMirrorView" : false,
      "startMonitorFromAppLaunch" : false
   }
}

Without connecting Arduino, SteamVR starts normally

SteamVR version:

Built Jul 8, 2021 at 07:05
Version 1.18.7 (1625702712)

I am trying to use your controller, when I use the "DistanceBetweenEyes" function from the default.vrsettings file, I get a cropped image with black sides.

Also the right image is inside the left image, you can get to see it from the right viewfinder lens.

How can we fix this problem, thanks

Headset Window is no longer showing after the update SteamVR
ValveSoftware/openvr#1780

As a temporary solution, you can use an old version of SteamVR.

1. Uninstall the current SteamVR.
2. Unzip this file to C:\Program Files\SteamVR.
3. Run "vrstartup.exe".

First of all thank you for this cool project, it looks very promising!

I already have the working headtracker with the Razor firmware and modified Output.ino file (as per your tutorial), but sadly I do not have any MIPI display yet.

SteamVR won't let setup and run the VR scene without an HMD attached, so I tried to use the null driver and "allowMultipleDrivers" in steamvr.vrsettings to launch the scene without a physical HMD, but looks like your driver is not being loaded if there is no physical display active (i.e. Arduino LEDs are not flashing as when COM port connection establishes, as well as I can connect to this COM port with another program, meaning it is not actively used).

Any other settings (like setting the COM port etc) are done per tutorial as well, so should be good to go.

Did you have any experience with settings this up without a real HMD? A friend of mine says he can borrow me a real helmet to test this, but I guess it will just use it's internal headtracker and drivers which will not work either. The null driver solution looks promising, but strangely the driver is not activated (though I can see it's being loaded in log files and debug console).