I'm looking for a way to determine the ambient light level for a program
simulating an electronic circuit involving a solar cell (photovoltaic cell),
where the output voltage will be set based on the measured ambient light level.
It looks like recent iMac and MacBook Pro models have a way to brighten/dim the
backlighting based on the ambient light level. The questions:
1) Is there a dedicated sensor for this, or is it using the front-facing
FaceTime camera?
2) If there is a dedicated sensor (such as a CdS cell or photo-transistor), is
there a way to get it's current measurement?
3) If not, how can I do the following
a) make a thread that
i) Captures a frame from the FaceTime camera
ii) Applies a grayscale filter (I'm guessing CoreImage probably already has
this, if you have an NSImage)
iii) Averages all the pixels to come up with a (rough) gauge of ambient
light level (as an unsigned byte) - preferably by using the graphics
coprocessor to unload the task from the main CPU!
iv) Communicates this back to the main thread.
b) Grab the info from the above thread without violating the "non-main
threads may not manipulate the UI" rule.
c) determine how long it takes the steps (a) above, so I can determine how
often to execute step (b) for my simulation.
Anyway, TIA. BTW, this is for MacOS X 10.8 or later, not iOS. :)
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