Battery level of WH-1000XM4 headphones and other series models, based on the WMI wrapper for Plug-and-Play devices.

The primary goal of the project is to get battery level of WH-1000XM4 headphones. Perhaps Xm4Battery might also works with similar models of headphones such as WH-1000XM4, WF-1000XM4 or WH-1000XM3-5-6-etc.

• Desktop Application
  • User interface
  • Tray icon mods
• Xm4Poller
  • Start and stop device polling
  • Xm4State
• Xm4Entity
  • Create XM4 instance
  • Is connected or not?
  • What was the last connected time?
  • Headphones battery level
  • Re/Connect already paired
• PnpEntity
  • How To find PNP-device?
  • Get and update a specific property of a device
  • Enumerate all properties of device
  • Enable or disable device
• Device specific properties
• XM4 related properties
• Windows Radio
• References

This Windows Forms application runs as a tray icon with no main window.
The ready-to-run version is available in the Latest Release section.

System requirements: Windows 10 x64, .NET Desktop Runtime 10.0 LTS

• F - 100% fully charged
• 4..9 - 40..90%
• 3 yellow - 30%
• 2 orange - 20%
• ! red - 10%
• X - headphones disconnected.
• % - headphones disconnected, the last known battery level was low (30% or lower).

When the headphones are disconnected, a tooltip displays their last known battery level and the date and time of their most recent connection.

🐭 Right Mouse Button opens a context menu:

• Connect - tries connect already paired headphones. ⚠
• Disconnect - tries disconnect headphones (not unpair, just disconnect). ⚠
• Launch at Startup - toggles whether the application automatically starts when Windows boots up. When ✅enabled, the application will launch automatically upon system startup.
• About - leads to this page.
• Quit - closes and unloads application at all.

The real icon size is 20x20 pixels. It is automatically scaled by system depend on display scaling factor.

Icon text color and background are defined in the Program.TrayIcon.cs → CreateXmIcon method:

// icon background color
var iconBackgroundBrush =
    uiBatteryLevel switch {
        <= DisconnectedLevel => Brushes.Transparent,
        <= CriticalPowerLevel => Brushes.Red,
        <= LowPowerLevel => Brushes.Orange,
        <= WarningPowerLevel => Brushes.Yellow,
        _ => Brushes.White // 40..100(F)
    };

// icon text color
var iconTextBrush =
    uiBatteryLevel switch {
        <= DisconnectedLevel => Brushes.WhiteSmoke,
        <= CriticalPowerLevel => Brushes.White,
        //<= LowPowerLevel => Brushes.Magenta,
        //<= WarningLevel => Brushes.Cyan,
        _ => Brushes.Black
    };

Font of the notification icon text (battery level or headphones status):

static readonly Font _notifyIconFont =
    new( "Segoe UI", 12.5f, FontStyle.Regular );

Automatically updates status of headphones.

var xm4result = Xm4Entity.Create();
if ( xm4result.IsFailed ) return 1;

Xm4Entity xm4 = xm4result.Value;

var statePoller = new Xm4Poller ( 
    xm4,
    ( previousState, newState ) => {
        // this handler is called when xm4 state changed:
        // connection status or/and battery charge level.
        // previousState <> newState - always unequal!
        UpdateUi_ForExample(newState);
    } );

statePoller.Start();

// starts main loop of window-less WinForms app
Application.Run();

// application was closed, quit
statePoller.Stop();

namespace WmiPnp.Xm4;

public record Xm4State
{
    public bool Connected   // true if connected, false - otherwise.
    public int BatteryLevel // battery charge level

var xm4result = Xm4Entity.CreateDefault();
if ( xm4result.IsFailed ) return; // headphones did not found at all

Xm4Entity _xm4 = xm4result.Value;

...
bool connected = _xm4.IsConnected;

We cannot determine the last connection time while the headphones are online and already connected. This property is only valid when the headphones are DISconnected.

Result<DateTime> dt = _xm4.LastConnectedTime;

bool disconnected = !_xm4.IsConnected;
if ( disconnected )
    Console.WriteLine( $"Last connected time: {_xm4.LastConnectedTime.Value}.\n" );
else
    var it_is_true = _xm4.LastConnectedTime.IsFailed; // can not get the last connected time

It retrieves the current battery level when the headphones are connected; otherwise, when they are disconnected, it returns the last known level.

int level = _xm4.BatteryLevel;

When headphones are used with multiple devices - such as a laptop, PC, or smartphone - you may need to reconnect them periodically. In this scenario, the headphones are already paired but currently disconnected.

For such cases, the WmiPnp module includes experimental methods: Xm4Entity.TryConnect() and the highly unstable Xm4Entity.TryDisconnect(). Both require the application to run with administrator privileges; otherwise, they are silently ignored.

If you're curious about completely turning off Bluetooth, see the section on Windows Radio.

First, we need to know either the name or the device id of the target device - or at least a partial match of its name.

• ByFriendlyName - exact a friendly name.
• ByDeviceId - exact a device id, like {GUID} pid.
• FindByFriendlyName - a part of a friendly name. Returns a list of founded devices IEnumerable<PnpEntity> or empty list otherwise.
• FindByNameForExactClass - same as FindByFriendlyName but with exact class name equality.
• EntityOrNone - a where part of WQL request to retrieve exact a single device only.
• EntitiesOrNone - a where part of WQL request to retrieve zero, one or several devices at once.

All of these methods return either an instance of PnpEntity or a Result.Fail if the specified device is not found.

Result<PnpEntity> result =
    PnpEntity.ByFriendlyName( "The Bluetooth Device #42" );

if ( result.IsSuccess ) { // device found
    PnpEntity btDevice = result.Value;
    ...
}

...
PnpEntity btDevice = result.Value;

while ( !Console.KeyAvailable ) {
    Result<DeviceProperty> propertyResult =
        btDevice.GetDeviceProperty(
            Xm4Entity.DeviceProperty_IsConnected );

    if ( propertyResult.IsSuccess ) {
        DeviceProperty dp = propertyResult.Value;
        bool connected = (bool)(dp.Data ?? false);

        Console.WriteLine(
            $"{btDevice.Name} is {(connected ? "connected" : "disconnected")}" );
    }

    // wait a little before the next attempt
    Thread.Sleep( TimeSpan.FromSeconds( 1 ) );
}

...
PnpEntity btDevice = result.Value;

IEnumerable<DeviceProperty> properties = btDevice.GetProperties();

foreach( var p in properties ) {
    Console.WriteLine( $"{p.KeyName}: {p.Data}" );
    ...
}

Some devices can be enabled or disabled.

...
PnpEntity btDevice = result.Value;

btDevice.Disable();
btDevice.Enable();

Key = {GUID} pid

• Key = {104EA319-6EE2-4701-BD47-8DDBF425BBE5} 2
• Type = 3 (Byte)

Data is in percents

• Key = {83DA6326-97A6-4088-9453-A1923F573B29} 15
• Type = 17 (Boolean)

Data = False → device is disconnected

• Key = {83DA6326-97A6-4088-9453-A1923F573B29} 102
• KeyName = DEVPKEY_Device_LastArrivalDate
• Type = 16 (FileTime)

Data = 20230131090906.098359+180 → 2023 Jan 31, 9:09:06 GMT+3

Key = {83da6326-97a6-4088-9453-a1923f573b29} 103

• WH-1000XM4 Hands-Free AG - exact name for PnpEntity to get a BATTERY LEVEL only.
• WH-1000XM4 - exact name for PnpEntity to get a STATE of the xm4.

• Key = {4340A6C5-93FA-4706-972C-7B648008A5A7} 2

• KeyName = DEVPKEY_Device_DevNodeStatus

• Type = 7 (Uint32)

• Connected = 25190410 (fall bit#25): value & 0x20000 == 0

• Disconnected = 58744842 (set bit#25): value & 0x20000 == 0x20000

This is the only property that provides the last connection date and time of the headphones, and it is available only when the headphones are DISconnected.

• Key = {2BD67D8B-8BEB-48D5-87E0-6CDA3428040A} 11
• KeyName = DEVPKEY_Bluetooth_LastConnectedTime
• Type = 16 (FileTime)

For ex.: Data = 20230131090906.098359+180 → 2023 Jan 31, 9:09:06, GMT+3

Contains the same data as the DEVPKEY_Bluetooth_LastConnectedTime property and behaves identically.

• Key = {2BD67D8B-8BEB-48D5-87E0-6CDA3428040A} 5
• Type = 16 (FileTime)

It is possible to use UWP APIs from a desktop application by setting the TargetFramework in your YourProject.csproj file to a Windows-specific .NET version, such as netX.x-windows10.0.xxxxx.x.

For example:

<PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net6.0-windows10.0.17763.0</TargetFramework>
    ...

With this setup, we can now use the Windows.Devices.Radios namespace:

using Windows.Devices.Radios;

public static async Task OsEnableBluetooth() =>
    InternalBluetoothState( enable: true );

public static async Task OsDisableBluetooth() =>
    InternalBluetoothState( enable: false );

private async Task InternalBluetoothState( bool enable )
{
    var result = await Radio.RequestAccessAsync();
    if (result != RadioAccessStatus.Allowed) return;

    var bluetooth =
        (await Radio.GetRadiosAsync())
        .FirstOrDefault(
            radio => radio.Kind == RadioKind.Bluetooth );

    await bluetooth?.SetStateAsync(
        enable ? RadioState.On
        : RadioState.Off );
}

• Sony Headphones Client public archive. This project features a PC alternative for the mobile-only Sony Headphones app. C++ Windows Linux macOS
• Enumerating windows device. Enumerating the device using the SetupDi* API provided with WinXP. CodeProject // 17 Jun 2006
• How to get the details for each enumerated device? MSDN, Archived Forums 421-440. Visual Basic
• Query battery level for WH-1000XM4 wireless headphones. GitHub gist. PowerShell
• Enable/disable already paired bluetooth devices. StackOverflow. How to connect to a paired audio Bluetooth device using Windows UWP API? PowerShell
• Talking to robots (or other devices) using Bluetooth from a Windows Runtime app. Windows.Devices.Bluetooth.Rfcomm namespace // May 7, 2014
• My Bluetooth headset can now be switched on and off from the command line. PowerShell