How can I know if my laptop is plugged into AC power via Matlab?

Hello,

is there a way to know through Matlab if the laptop is currently plugged in AC power or running on battery?

Thanks,

Mark

Answer 1

[Les Beckham]

That error message (''pmset' is not recognized as an internal or external command, operable program or batch file) is a Windows error message.

Based on this blog post you can determine this in Windows using an undocumented/unsupported class in Powershell:

https://devblogs.microsoft.com/scripting/using-windows-powershell-to-determine-if-a-laptop-is-on-battery-power/

Put this Powershell script wherever you wish (like in your "Documents" folder, for instance):

Function Test-IsOnBattery
{
Param(
[string]$computer
)
if ([BOOL](Get-WmiObject -Class BatteryStatus -Namespace root\wmi -ComputerName $computer).PowerOnLine)
    {Write-Output "On AC Power"}
else
    {Write-Output "On Battery"}
} #end function test-IsOnBattery
Test-IsOnBattery -computer <YourComputerName>

Name the file Test-IsOnBattery.ps1.

Then call it from Matlab like this:

[status, output] = system("powershell C:/Users/<YourUserName>/Documents/Test-IsOnBattery");

Then you can test the result like this:

if strfind(output, "AC")
    disp('AC')
else
    disp('Battery')
end

I hope this helps.

[Walter Roberson]

I am sure that if the original poster were using Microsoft Windows they would have said so, and would not have tried the solution that I posted that was clearly marked as being for MacOS. We must continue to assume that they are using a a Mac laptop, but it is not clear whether they are using a mid-2012 MacBook Pro or something newer, or a MacBook Air. All we can rule out is Mac Mini (not a laptop form factor) or Mac Pro (tower, not laptop) or iMac (desktop not laptop)

If they happen to be using Windows under Parallels or VMware then these are also relevant:

https://answers.microsoft.com/en-us/windows/forum/windows_7-security/detecting-if-running-on-battery-and-running-a/23316a1e-1876-4918-b526-187839de675a

https://devblogs.microsoft.com/scripting/how-can-i-tell-whether-a-laptop-computer-is-running-off-batteries/

There are also posts available showing the Microsoft api calls but I do not know if it is possible to invoke those without some mex. Maybe through the .NET interface??

[Les Beckham]

Walter,

I think you may have made a huge assumption about the platform that the OP is using based on the very brief original question. What part of that question led you to assume MacOS?

Also, while the link you provided as an answer may have ended in the characters "osx", I hardly think that would qualify as "clearly marked as being for MacOS".

The fact that the OP tried your suggestion, which is likely a good one if the assumption of the platform were correct, does not neccessarily confirm that assumption.

I'm not trying to start an argument. I'm mainly confused about why you assumed the Mac platform and responded to my post with one that implied that I missed something obvious in the original post that made my response irrelevant ("We must continue to assume that they are using a Mac laptop").

Best regards and thank you for all of the help that you have provided to me and all of the Matlab Answers community.

Les

[Walter Roberson]

Quoting the stackoverflow post:

Exactly as the title says -- I'm looking for a way, in OSX, to tell me if my laptop is currently plugged in so that I can start/pause CPU intensive tasks as necessary.

I just checked now and was surprised to see that Microsoft does still make one variety of laptop (Surface Pro 3); I thought they had moved entirely to tablets.

[Les Beckham]

Still confused about why you are responding as if you disagree with my answer and subsequent comments.

The stackoverflow reference which refers to OSX is almost 6 years old and is referenced in your answer, not in the original question (from today), which mentioned nothing about any operating system or host platform whatsoever.

The original question was unclear about the OS, but the comment response to your initial answer cited an error message which clearly showed (though not mentioned by the OP) that the OP was using a Windows system.

Have a good night.

[Walter Roberson]

Unfortunately, more than two weeks later, the original poster still has not indicated anything further about operating system, so we still don't know. :(

[Les Beckham]

Yes. Quite unfortunate, as I found this question quite interesting to investigate and experiment with. Happy holidays to you and yours, Walter.

[Mark Golberg]

OS - windows 10.

Les Beckham solution worked as a charm.

THANK YOU!

Answer 2

[Walter Roberson]

https://stackoverflow.com/questions/21249419/how-do-i-programatically-detect-if-my-laptop-is-plugged-in-or-not-osx

You can adapt that in MATLAB by using system() of the pmset piped to head, and receive the result as the second output of system, and do the string testing in MATLAB.

[Mark Golberg]

I don't follow...

can you please write the exact matlab code I should enter?

[Walter Roberson]

 [status, msg] = system('pmset -g ps|head -1');
  if strfind(msg, 'AC Power')
    It is plugged in
   else 
     It is not plugged in 
    end

[Mark Golberg]

I receive the follwoing :

msg =

''pmset' is not recognized as an internal or external command,

operable program or batch file.

'

Am I missing something?

[Walter Roberson]

That is very odd. The only way I can think of that that could happen is is if you installed something like Parallels in compatibility mode and then accidentally linked /bin/bash to /Applications/Parallels13.02.app/contents/bin/command.exe -- but if you had done that I would tend to doubt that you would have been able to boot all the way.

Hmmm... No, even if you were using R2012a with OS 10.15 that error message does not make any sense, too many other things would have to have gone wrong.

Is your laptop "Late 2012" or would it happen to be "Mid 2012" or earlier? MATLAB does happen to be compatible with selected Mid 2012 models but not Early 2012 models (not if you are using R2019b and OS 10.15); I ask because we just might need to guide you through using the Recovery Partition to fix /bin/bash but the mid 2012 models did not yet have Recovery Partition and have to be recovered from DVD.