- (IBAction)buttonTapped:(id)sender {

    if (sender == self.startDetailTime) {
        self.startNow = [[NSDate alloc] init];
        self.presetTimer.timer= [NSTimer timerWithTimeInterval:1/60.0 target:self selector:@selector(timerFired:) userInfo:nil repeats:YES];

        [[NSRunLoop currentRunLoop] addTimer:self.presetTimer.timer forMode: NSRunLoopCommonModes];

    }
    if (sender == self.pauseDetailTime) {

        self.totalTime =  self.totalTime - self.totalSessonTime;
        [self.presetTimer.timer invalidate];

    }

}