Powershell Auto Mute, when headphones are accidently unplugged.

INTRODUCTION:

Do you know mobile phones have an inbuilt feature to Auto mute a playing song/music,  if by mistake you plug out your earphones from the jack, that prevents your phone to keep playing the music on speakers, which could be quite embarrassing in some surroundings and situations, but unfortunately we don’t have such a feature available on our desktops/laptops 😦

And I was victim of such an embarrassing situation a few days back, when I was listening to some music on my developer workstation in my office with my headphones on and tried to rest my head on the chair’s backrest in relaxing position, due to tension the cable got unplugged from headphone jack and allowed the music to be played for a while from my laptop speakers and it took me few seconds to realize that I screwed it and everybody in the office is  looking at me 😀 . Somehow in hurry I managed to mute my PC. Phew!

It was embarrassing but the good part was I was at least not listening to Taylor Swift 😛 , So I thought why not to look for a solution available to fix this for me? Really I didn’t care much about finding one but was more interested in making one with Powershell! 🙂

THE IDEA:

1. Run a background PowerShell script (Hidden preferred) always when your machine is up
2. That monitors a device plug – IN/OUT events
3. If a Device Plug OFF event is triggered, make sure to MUTE your machine
4. Or, in the case of Plug-IN event is generated UNMUTE the machine.

MAKING IT WORK:

• Running the script in background:  We can create a basic Task in Windows task scheduler to run a PowerShell script whenever machine whenever computer starts to run a PowerShell scriptThis will make sure our script is always running in the background, waiting for a device to be plugged In/out
• Capture Device Plug-In/Out Events:  After some googling and research I found a WMI class Win32_DeviceChangeEvent that represents device change/modification events on a windows machine. Here  is the link to MSDN Documentation of the WMI class.It clearly mentions that, Event Type 3 generated under this class is Device Removed and Event Type 2 is Device arrival (plugged in).

  After knowing this I  believe, now it’s easier to register a WMI event using Powershell cmdlet

  Register-WMIEvent

  and wait for any of the above events (Event Type 2 or 3) to occur using cmdlet

  Wait-Event

  

• Handling the events: In the case  Event type 3 is triggered, which as per Microsoft’s documentation means – A device plugged off (Removal) event, then we should MUTE our Machine, and when the device is plugged in (Arrival) event is generated we need to UNMUTE the machine..
• NOTE: We need to access Audio API on our Windows machine, for which we’ve to add some C# code in our script. * Source

SCRIPT:

Wrapping up everything in a PowerShell script looks something like this

	[cmdletbinding()]
	Param()
	#Adding definitions for accessing the Audio API
	Add-Type -TypeDefinition @'
	using System.Runtime.InteropServices;
	[Guid("5CDF2C82-841E-4546-9722-0CF74078229A"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
	interface IAudioEndpointVolume {
	// f(), g(), ... are unused COM method slots. Define these if you care
	int f(); int g(); int h(); int i();
	int SetMasterVolumeLevelScalar(float fLevel, System.Guid pguidEventContext);
	int j();
	int GetMasterVolumeLevelScalar(out float pfLevel);
	int k(); int l(); int m(); int n();
	int SetMute([MarshalAs(UnmanagedType.Bool)] bool bMute, System.Guid pguidEventContext);
	int GetMute(out bool pbMute);
	}
	[Guid("D666063F-1587-4E43-81F1-B948E807363F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
	interface IMMDevice {
	int Activate(ref System.Guid id, int clsCtx, int activationParams, out IAudioEndpointVolume aev);
	}
	[Guid("A95664D2-9614-4F35-A746-DE8DB63617E6"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
	interface IMMDeviceEnumerator {
	int f(); // Unused
	int GetDefaultAudioEndpoint(int dataFlow, int role, out IMMDevice endpoint);
	}
	[ComImport, Guid("BCDE0395-E52F-467C-8E3D-C4579291692E")] class MMDeviceEnumeratorComObject { }
	public class Audio {
	static IAudioEndpointVolume Vol() {
	var enumerator = new MMDeviceEnumeratorComObject() as IMMDeviceEnumerator;
	IMMDevice dev = null;
	Marshal.ThrowExceptionForHR(enumerator.GetDefaultAudioEndpoint(/*eRender*/ 0, /*eMultimedia*/ 1, out dev));
	IAudioEndpointVolume epv = null;
	var epvid = typeof(IAudioEndpointVolume).GUID;
	Marshal.ThrowExceptionForHR(dev.Activate(ref epvid, /*CLSCTX_ALL*/ 23, 0, out epv));
	return epv;
	}
	public static float Volume {
	get {float v = -1; Marshal.ThrowExceptionForHR(Vol().GetMasterVolumeLevelScalar(out v)); return v;}
	set {Marshal.ThrowExceptionForHR(Vol().SetMasterVolumeLevelScalar(value, System.Guid.Empty));}
	}
	public static bool Mute {
	get { bool mute; Marshal.ThrowExceptionForHR(Vol().GetMute(out mute)); return mute; }
	set { Marshal.ThrowExceptionForHR(Vol().SetMute(value, System.Guid.Empty)); }
	}
	}
	'@ -Verbose
	While($true)
	{
	#Clean all events in the current session since its in a infinite loop, to make a fresh start when loop begins
	Get-Event | Remove-Event -ErrorAction SilentlyContinue
	#Registering the Event and Waiting for event to be triggered
	Register-WmiEvent -Class Win32_DeviceChangeEvent
	Wait-Event -OutVariable Event |Out-Null
	$EventType = $Event.sourceargs.newevent | `
	Sort-Object TIME_CREATED -Descending | `
	Select-Object EventType -ExpandProperty EventType -First 1
	#Conditional logic to handle, When to Mute/unMute the machine using Audio API
	If($EventType -eq 3)
	{
	[Audio]::Mute = $true
	Write-Verbose "Muted [$((Get-Date).tostring())]"
	}
	elseif($EventType -eq 2 -and [Audio]::Mute -eq $true)
	{
	[Audio]::Mute = $false
	Write-Verbose "UnMuted [$((Get-Date).tostring())]"
	}
	}

view raw PSAutoMute.ps1 hosted with ❤ by GitHub

You can also fork my Github repo of the script here and feel free to contribute 🙂

HOW TO RUN:

You can run the script on demand like in the below animation or you can create a task in task scheduler to make it run (Hidden) always when your machine starts.

Hope you’ll find the script useful or at least gain some knowledge. Thanks for reading, Cheers! 🙂

Follow @SinghPrateik