A starting point for an NSTimer that has a weak reference to its target. ARC only.

NSWeakTimer.m

//
//  NSWeakTimer.m


#import "NSWeakTimer.h"

@interface NSWeakTimerTarget : NSObject
@property (assign) id target;
@property (assign) SEL selector;
@property (assign) NSTimer* timer;
@end



@implementation NSWeakTimerTarget

- (void) fire
{
    if(self.target)
    {
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warc-performSelector-leaks"
        [self.target performSelector:self.selector withObject:nil];
#pragma clang diagnostic pop
    }
    else
    {
        [self.timer invalidate];
    }
}

@end


@implementation NSWeakTimer

+ (NSTimer *) scheduledTimerWithTimeInterval:(NSTimeInterval)ti target:(id)aTarget selector:(SEL)aSelector userInfo:(id)userInfo repeats:(BOOL)yesOrNo
{
    NSWeakTimerTarget* timerTarget = [[NSWeakTimerTarget alloc] init];
    timerTarget.target = aTarget;
    timerTarget.selector = aSelector;
    timerTarget.timer = [NSTimer scheduledTimerWithTimeInterval:ti target:timerTarget selector:@selector(fire) userInfo:userInfo repeats:yesOrNo];
    return timerTarget.timer;
}

@end