How to pass a variable between UIViewControllers

Question

I have a Detail View Controller which contains data passed from a Table View:

#import "BRProjectsDetailViewController.h"

@interface BRProjectsDetailViewController ()

@end

@implementation BRProjectsDetailViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (IBAction)unwindBackToProjectsDetailViewController:(UIStoryboardSegue *)seque;
{
    NSLog(@"unwindBackToHomeViewController!");
}

///used to feed data from homeview into detail view
-(void) viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    NSLog(@"viewWillAppear");
    NSString *name = self.projects[@"name"];
    self.title = name;
    NSString *description = self.projects[@"description"];
    self.descriptionView.text = description;
}

I want to take the variable string labelled 'name' above and pass the contents of this to a collection view controller, currently coded below. At the moment, before doing conditioning I'm just trying to get a response from my NSLog. Currently it just returns null: . This is just an excerpt from the code: Can anyone help please?

#import "BRCollectionViewController.h"
#import "BRCollectionViewCell.h"
#import "BRProjectsDetailViewController.h"

@interface BRCollectionViewController ()
{
    ///add arrays for photos - to update once photos known
    NSArray *imagesOne;
    NSArray *imagesTwo;
}
@end


@implementation BRCollectionViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad {
    //added this
    NSString *name;
    NSLog(@"%@", name);
    //
}

@end