TSNPeerBluetooth is a peer-to-peer networking over Bluetooth LE library for iOS.

I created TSNPeerBluetooth to serve as an example of how to use Apple's Core Bluetooth framework to define a custom Bluetooth LE service and set of service characteristics that allows nearby peers to exchange presence, location, and status updates. TSNPeerBluetooth acts as both a Bluetooth LE accessory itself and as a consumer of its own Bluetooth LE accessory, so it's pretty useful as an Bluetooth LE programming sample for iOS.

In order to make TSNPeerBluetooth a more useful example, I created an example application that uses it called Bubble Chat. Bubble Chat allows iOS devices that are within Bluetooth LE communications range to see one another on a map and exchange chat messages.

I've written a blog posting about BubbleChat and TSNPeerBluetooth which includes a video that shows BubbleChat in action.

Clone TSNPeerBluetooth and / or Bubble Chat and give them a go. Better yet, fork them and send some pull requests.

Using TSNPeerBluetooth

Add TSNPeerBluetooth to your podfile.

pod 'TSNPeerBluetooth'

And install it using:

pod install

How TSNPeerBluetooth Works

Allocate and initialize a new instance of the TSNPeerBluetooth class as shown below.

// Allocate and initialize the service type.
NSUUID * serviceType = [[NSUUID alloc] initWithUUIDString:@"FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF"];

// Static declarations.
static NSString * const PEER_IDENTIFIER_KEY = @"PeerIdentifierKey";

// Obtain user defaults and see if we have a serialized peer identifier. If we do,
// deserialize it. If not, make one and serialize it for later use.
NSUserDefaults * userDefaults = [NSUserDefaults standardUserDefaults];
NSData * peerIdentifierData = [userDefaults dataForKey:PEER_IDENTIFIER_KEY];
if (!peerIdentifierData)
{
    // Create a new peer identifier.
    UInt8 uuid[16];
    [[NSUUID UUID] getUUIDBytes:uuid];
    peerIdentifierData = [NSData dataWithBytes:uuid
                                        length:sizeof(uuid)];

    // Save the peer identifier in user defaults.
    [userDefaults setValue:peerIdentifierData
                    forKey:PEER_IDENTIFIER_KEY];
    [userDefaults synchronize];
}
NSUUID * peerIdentifier = [[NSUUID alloc] initWithUUIDBytes:[peerIdentifierData bytes]];

// Allocate and initialize the peer Bluetooth context.
_peerBluetooth = [[TSNPeerBluetooth alloc] initWithServiceType:serviceType
                                                peerIdentifier:peerIdentifier
                                                      peerName:[[UIDevice currentDevice] name]];
[_peerBluetooth setDelegate:(id<TSNPeerBluetoothDelegate>)self];

Use your own UUID in place of FFFFFFFF-FFFF-FFFF-FFFF-FFFFFFFFFFFF.

Once you have a TSNPeerBluetooth instance, use the start method to start your peer:

[_peerBluetooth start];

And the stop method to stop your peer:

[_peerBluetooth stop];

To update your peer's location, call the updateLocation method:

[_peerBluetooth updateLocation:location];

To update your peer's status, call the updateStatus method:

[_peerBluetooth updateStatus:@"My new status!"];

Implement the TSNPeerBluetoothDelegate to receive callbacks for TSNPeerBluetooth events.

peerBluetooth:didConnectPeerIdentifier:peerName:peerLocation: is called when a new peer is discovered and connected:

// Notifies the delegate that a peer was connected.
- (void)peerBluetooth:(TSNPeerBluetooth *)peerBluetooth
didConnectPeerIdentifier:(NSUUID *)peerIdentifier
             peerName:(NSString *)peerName
         peerLocation:(CLLocation *)peerLocation
{
...
}

peerBluetooth:didDisconnectPeerIdentifier: is called when a previously connected peer is disconnected:

// Notifies the delegate that a peer was disconnected.
- (void)peerBluetooth:(TSNPeerBluetooth *)peerBluetooth
didDisconnectPeerIdentifier:(NSUUID *)peerIdentifier
{
...
}

peerBluetooth:didReceivePeerLocation:fromPeerIdentifier: is called when a peer updates its location:

// Notifies the delegate that a peer location was received.
- (void)peerBluetooth:(TSNPeerBluetooth *)peerBluetooth
didReceivePeerLocation:(CLLocation *)peerLocation
   fromPeerIdentifier:(NSUUID *)peerIdentifier
{
...
}

peerBluetooth:didReceivePeerStatus:fromPeerIdentifier: is called when a peer updates its status:

// Notifies the delegate that a peer status was received.
- (void)peerBluetooth:(TSNPeerBluetooth *)peerBluetooth
 didReceivePeerStatus:(NSString *)peerStatus
   fromPeerIdentifier:(NSUUID *)peerIdentifier
{
...
}

(See Bubble Chat's TSNAppContext.m file for an example implementation TSNPeerBluetoothDelegate.)

License

TSNPeerBluetooth is released under an MIT license, meaning you're free to use it in both closed and open source projects. However, even in a closed source project, please include a publicly-accessible copy of TSNPeerBluetooth's copyright notice, which you can find in the LICENSE file.

Feedback

If you have any questions, suggestions, or contributions to TSNPeerBluetooth, please feel free to contact me.