Torch code for iOS6

gistfile1.m

@property (nonatomic,strong)AVCaptureSession *captureSession;
@property (nonatomic,strong)AVCaptureDevice *device;
@property (weak, nonatomic) IBOutlet UISlider *torchLevelSlider;

- (void)setupTorch
{
    NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    for (AVCaptureDevice *d in devices)
        if (d.hasTorch && [d isTorchModeSupported:AVCaptureTorchModeOn]) {
            self.device = d;
            break;
        }

    if (self.device) {
        self.captureSession = [[AVCaptureSession alloc] init];
        AVCaptureDeviceInput *videoIn = [[AVCaptureDeviceInput alloc] initWithDevice:_device error:nil];
        if ([_captureSession canAddInput:videoIn])
            [_captureSession addInput:videoIn];
    }

    [self torchLevelChanged:self.torchLevelSlider];
}

- (IBAction)torchLevelChanged:(UISlider *)sender {
    float value = sender.value;
    NSError *error;
    [_device lockForConfiguration:&error];
    if (value == 0.0f) {
        _device.torchMode = AVCaptureTorchModeOff;
    } else {
        if (value == 1.0f)
            value = AVCaptureMaxAvailableTorchLevel;
        [_device setTorchModeOnWithLevel:value error:&error];
    }
    [_device unlockForConfiguration];
}