Implementing a strobe function - ios

Question

So I am trying to create a LED strobe light and I have managed to make a on/off switch for the light. Here is my code:
#implementation ViewController
- (void) setTorchOn:(BOOL)isOn
{
AVCaptureDevice* device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
[device lockForConfiguration:nil];
[device setTorchMode:isOn ? AVCaptureTorchModeOn : AVCaptureTorchModeOff];
[device unlockForConfiguration];
}
-(IBAction)changedSate:(id)sender {
UISwitch *switchValue = (UISwitch*)sender;
[self setTorchOn:[switchValue isOn]];
I was wondering if anyone could help me with this part.

Answer 1

Just make a loop that continuously turns the torch on and off. The type of loops depends on how you wish this to be implemented.

Answer 2

I think you should use the NSTimer class to repeatedly toggle the torch. There are other ways, but just do not loop with a sleep() call.
// Have an NSTimer* timer and BOOL torchOn and volatile BOOL stopStrobe property in your class...
- (void) startFlashing{
self.timer = [[NSTimer alloc] initWithFireDate:[NSDate timeInvervalSinceNow: 0] interval:0.1 target:self selector:#selector(toggleTorch) userInfo:nil repeats:YES];
}
- (void) toggleTorch{
if (stopStrobe){
[self.timer invalidate];
}
torchOn = !torchOn
[self setTorchOn:torchOn];
}
// Set stopStrobe to YES elsewhere in your program when you want it to stop.
is probably what you're looking for.
UPDATE: I know this isn't what you originally asked, but I know it's often best to learn by example, so here is the full example of using this (untested):
#interface ViewController()
#property(nonatomic) BOOL torchOn;
#property(atomic) BOOL stopStrobe;
#end
#implementation ViewController
- (id) init{
self = [super init];
if (self){
self.torchOn = NO;
self.stopStrobe = NO;
}
}
- (void) setTorchOn:(BOOL)isOn
{
AVCaptureDevice* device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
[device lockForConfiguration:nil];
[device setTorchMode:isOn ? AVCaptureTorchModeOn : AVCaptureTorchModeOff];
[device unlockForConfiguration];
}
- (void) toggleTorch{
if (stopStrobe){
[self.timer invalidate];
}
self.torchOn = !self.torchOn
[self setTorchOn:self.torchOn];
}
- (void) startFlashing{
self.timer = [[NSTimer alloc] initWithFireDate:[NSDate timeInvervalSinceNow: 0] interval:0.1 target:self selector:#selector(toggleTorch) userInfo:nil repeats:YES];
}
-(IBAction)changedSate:(id)sender {
UISwitch *switchValue = (UISwitch*)sender;
if ([switchValue isOn]{
self.stopStrobe = NO;
[self startFlashing];
}
else{
[self.stopStrobe = YES];
}
}
This will start the flashing whenever you turn the switch on and stop it once you turn the switch off.