Light Level

light.m

/** 
 * LightSensor
 *
 * Extracted from http://stackoverflow.com/questions/10061028/isight-ambient-sensor 
**/

#include <stdio.h>
#include <IOKit/IOKitLib.h>

#import <Foundation/Foundation.h>

int getLightLevel() 
{
    
    uint32_t outputs = 2;
    uint64_t values[outputs];
	
    io_connect_t port = 0;
	
    // Get the light sensor service
    io_service_t lightSensor = IOServiceGetMatchingService(kIOMasterPortDefault,
                                                           IOServiceMatching("AppleLMUController"));
	
    // Connect the service at the given port
    IOServiceOpen(lightSensor, mach_task_self(), 0, &port);
	
    // Access it, assigning the levels the sensors measure to `values`
    IOConnectCallMethod(port, 0, nil, 0, nil, 0, values, &outputs, nil, 0);
	
    // Disconnects our service 
    IOConnectRelease(lightSensor);

    // Return the first value (I believe this is the iSight camera)
    return (int)values[0];
			
}

int main (int argc, char *argv[]) 
{
    fprintf(stdout, "%i", getLightLevel() );
    return 0;
}

Makefile

all:
	gcc light.m -std=c99 -framework Foundation -framework IOKit -o light  

clean:
	rm -f light