Hi,
the simple way to increase/decrease monitor "brightness" is to P/Invoke the Gamma-Value with
SetDeviceGammaRamp
function in GDI32.dll.
The reason why brightness is quoted is it's not really setting the real monitor brightness when changing gamma value, but it really looks like.
The disadvantage is compability to graphic cards, some graphic cards doesn't seem to allow this because of their architecture.
Function at Pinvoke.net
http://www.pinvoke.net/default.aspx/gdi32.setdevicegammaramp[
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CP
Setting Screen Brightness in C#[
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The safe way would be sending DDC(Display Data Channels)/CI-Commands (for VGA/DVI). But this is not a weekend task, so with a commercial library it could be done very quick ;) Both cases are overdriven for your pruposes (except you really want to spend money for this).
http://www.nicomsoft.com/products/i2c/[
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Kinect SDK provides interfaces for audio, acoustic noise and echo cancellation.
Or do you want to control Windows Volume?
For XP, you could also P/Invoke winmm.dll
waveoutsetvalue
.
http://www.pinvoke.net/default.aspx/winmm.waveoutsetvolume[
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Since Win7 audio api changed, in a few words, you should start with Windows Multimedia Device (MMDevice) API and search for audio endpoint devices.
http://msdn.microsoft.com/en-us/library/windows/desktop/dd316556%28v=vs.85%29.aspx[
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Naudio is a great easy-to-use library for this:
http://naudio.codeplex.com/[
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Best Regards