Can I expect WMI to be able to access functions of a device? RRS feed

  • Question

  • Hi,

    For some time now, I have been looking for a way to Turn on and Turn off the LED flash light on my Windows 8 tablet.

    I have not been able to succeed using the easy method (from a Windows Store App), because I am wrting a Desktop Application. I have asked for tips on this forum, but I haven´t received anything that I could work with. 

    So now I'm at a point in which I am looking a bit deeper. I have found the driver LM3554.SYS, and I found it in the Device Manager as 'Flash LM3554'.

    I read an article about WMI in which I saw that it was possible to interrogate devices and somtimes even to manipulate settings. I downloaded the WMI Code Generator and after some searchning I found the device.

    Before I spend a lot of time on this..... Is there anyone who can tell me if it should be feasible to manipulate the device to turn on/off the flash light (so not only enable and disabling the device)?

    Looking forward to your reply,


    • Moved by Mike Feng Monday, March 18, 2013 2:31 PM
    • Moved by Zoltán HorváthMVP Thursday, April 4, 2013 11:15 AM OP asked to move this thread
    Monday, March 11, 2013 8:13 AM

All replies

  • How is it turned on and off now? With software or hardware? If you're trying to use it as a strobe it may not be designed to do that.

    The LM3554 is a 2MHz fixed frequency, current mode synchronous boost converter.  The device is designed to operate as a dual    600mA (1.2A total) constant-current  driver for high-current white LEDs, or as a regulated 4.5V or 5V voltage source.    

    The dual high-side current sources allow for grounded cathode LED operation. An adaptive regulation method ensures the current    source for each LED remains in regulation and maximizes efficiency. 

    The main features include: an I    <super>2</super>C-compatible interface for controlling the LED current or the desired output voltage, a hardware Flash enable input for direct    triggering of the Flash pulse, and dual TX inputs which force the Flash pulse into a low-current Torch mode allowing for synchronization    to RF power amplifier events or other high-current conditions. Additionally, an active high hardware enable (HWEN) input provides    a hardware shutdown during system software failures.

    Five protection features are available within the LM3554 including a software selectable input voltage monitor, an internal    comparator for interfacing with an external temperature sensor, four selectable current limits to ensure the battery current    is kept below a predetermined peak level, an over-voltage protection feature to limit the output voltage during LED open circuits,    and an output short circuit protection which limits the output current during shorts to GND.   Additionally, the device provides     various fault indicators including: a thermal fault flag indicating the LED temperature has tripped the thermal threshold,    a flag indicating a TX event has occurred, a flag indicating the  flash timeout counter has expired, a flag indicating the    devices die temperature has reached the thermal shutdown threshold, and a flag indicating an open or short LED.


    You've taught me everything I know but not everything you know.

    Monday, March 11, 2013 12:26 PM
  • Hi,

    I'm tying to use the LED as a flash for the Camera that is right next to it. I am developing for Windows 8 desktop and (although it is available on Windows Store Apps like Youcam for HP) I have not been able to find a way to access it.

    When the driver is loaded the LED does not light up, so it is not triggered by loading or unloading of the driver.... that is why I mentioned the functions of the device.

    There is a windows 8 property called KSPROPERTY_CAMERACONTROL_FLASH_PROPERTY in Extended Camera Control Properties (Windows Drivers) but the only mention of this is on the MS website itself... I have not been able to find anyone who can tell me where I can find the Extende Camera Control Properties or how (or even if) I can use them in C# or VB.NET. I have the feeling that this is used by Youcam for HP (which is a different version to the normal one (which has no flash capability).

    I have read the attached document, there is also a tester program of some sort, but that fails due to a USB/Serial error... so no help from there.

    This is my attempt to think outside of the box, but it would be great to find a DLL or so that will provide the function that I require..... just to turn on and off the LED.


    Monday, March 11, 2013 1:07 PM
  • "that fails due to a USB/Serial error"

    What is the error and why does it fail?

    Monday, March 11, 2013 2:36 PM
  • Hi John,

    No idea why it fails, the GUI just shows the text: 'USB Initialisation error' as a label on the form just beneath the logo.... I have profiled (dependency walker) the application and it does not do anything after loading under Windows8 Desktop. So no joy from that application.


    Monday, March 11, 2013 7:52 PM
  • "Windows 8 tablet"

    If it's RT, post to the RT forum.

    Am I hacked or is MSDN hacked?  Someone hacked "Windows" and inserted a link as has been done with many other key words.

    Monday, March 11, 2013 8:11 PM
  • My tablet runs Windows 8 Professional. The application is running in Desktop mode, my questions are all about accessing the LED Flash light in Windows 8 Desktop.

    • Edited by John1969 Tuesday, March 12, 2013 7:32 AM
    Tuesday, March 12, 2013 7:30 AM
  • Hi John,

    I moved this thread to "where is the forum for ..." to look for an appropriate forum, since based on my understanding, it is less related to VB.

    Thank you for your understanding and support.

    Best regards,

    Mike Feng
    MSDN Community Support | Feedback to us
    Develop and promote your apps in Windows Store
    Please remember to mark the replies as answers if they help and unmark them if they provide no help.

    Tuesday, March 12, 2013 9:21 AM
  • Hi Mike,

    Sorry, I forgot to mention that I am using VB.NET.... To me, it seemed that the VB.NET forum was the correct one. I also feel that the "Where is the forum for..." is way to find the correct forum for a specific question......

    My question is regarding a specific technique from VB.NET but not a Windows Drivers question.

    Anyways, I'm getting nowhere with the solution.... it may be a dead-end after all.


    Tuesday, March 12, 2013 11:14 AM
  • I can move this back if you want. I'm sure someone knows the answer.


    Ed Price (a.k.a User Ed), SQL Server Customer Program Manager (Blog, Small Basic, Wiki Ninjas, Wiki)

    Answer an interesting question? Create a wiki article about it!

    Wednesday, March 27, 2013 4:11 PM
  • Another forum idea is the Connected Services Framework forum:

    Ed Price (a.k.a User Ed), SQL Server Customer Program Manager (Blog, Small Basic, Wiki Ninjas, Wiki)

    Answer an interesting question? Create a wiki article about it!

    Wednesday, March 27, 2013 9:58 PM
  • Hi Ed,

    Yes please, can you move it back?



    Thursday, April 4, 2013 10:30 AM
  • Hi John,

    I've moved it.



    Thursday, April 4, 2013 11:16 AM