I'm sure sending an HTTP request every time the slider moves will be just fine…

gistfile1.m

-(IBAction)sliderValueChanged:(id)sender {
    UISlider *currentSlider = (UISlider*)sender;
    
    NSString *initalJSONRequest = [NSString stringWithFormat:@"{\"on\":\"true\""];
    NSString *jsonRequest;
    
    if (currentSlider == self.brightnessSlider) {
        self.brightnessValueLabel.text = [NSString stringWithFormat:@"%f", currentSlider.value];
        jsonRequest = [initalJSONRequest stringByAppendingFormat:@",\"bri\":%.0f}", currentSlider.value];
    }
    else if (currentSlider == self.hueSlider) {
        self.hueValueLabel.text = [NSString stringWithFormat:@"%f", currentSlider.value];
        jsonRequest = [initalJSONRequest stringByAppendingFormat:@",\"hue\":%.0f}", currentSlider.value];
    }
    else if (currentSlider == self.saturationSlider) {
        self.saturationValueLabel.text = [NSString stringWithFormat:@"%f", currentSlider.value];
        jsonRequest = [initalJSONRequest stringByAppendingFormat:@",\"sat\":%.0f}", currentSlider.value];
    }
    else if (currentSlider == self.xSlider || currentSlider == self.ySlider) {
        self.xValueLabel.text = [NSString stringWithFormat:@"%f", currentSlider.value];
        jsonRequest = [initalJSONRequest stringByAppendingFormat:@",\"hue\":%.0f}", currentSlider.value];
    }
    else if (currentSlider == self.ctSlider) {
        self.ctValueLabel.text = [NSString stringWithFormat:@"%f", currentSlider.value];
        jsonRequest = [initalJSONRequest stringByAppendingFormat:@",\"ct\":%.0f}", currentSlider.value];
    }
    
    NSURL *url = [[self urlForLightbulb:self.lightbulbSelectionControl.selectedSegmentIndex+1] URLByAppendingPathComponent:@"state"];
    NSLog(@"%@", url);
    
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:url];
    NSData *requestData = [NSData dataWithBytes:[jsonRequest UTF8String] length:[jsonRequest length]];
    NSLog(@"%@", jsonRequest);
    
    [request setHTTPMethod:@"PUT"];
    [request setHTTPBody: requestData];
    
    [NSURLConnection connectionWithRequest:request delegate:self];
    
}