I have created two iOS apps; one a Bluetooth LE peripheral that advertises a service, and one a Bluetooth LE central that scans for the advertised service. The peripheral is running on my iPhone5s, and the central is running on my iPad Mini. I initially set the central up to scan for the specific advertised service, but later changed it to listen to any service. In either case, the iPad Mini app acting as a central never detects any advertised service. I am uncertain whether its a problem with the way I setup the peripheral manager to advertise, or if its a problem with the way I setup the central manager to scan, or a device configuration problem. Please offer suggestions or tests I can perform to get this working.
The following is the relevant code for the iPhone5s app acting as a peripheral:
CBPeripheralManager *peripheralManager = [[CBPeripheralManager alloc] initWithDelegate:self queue:nil options:nil];
CBUUID *immediateAlertServiceUUID = [CBUUID UUIDWithString: IMMEDIATE_ALERT_SERVICE_UUID];
CBUUID *alertLevelCharacteristicUUID = [CBUUID UUIDWithString: ALERT_LEVEL_CHARACTERISTIC_UUID];
CBUUID *myCustomCharacteristicUUID = [CBUUID UUIDWithString: MY_CUSTOM_CHARACTERISTIC_UUID];
alertLevelCharacteristic =
[[CBMutableCharacteristic alloc] initWithType:alertLevelCharacteristicUUID
properties:CBCharacteristicPropertyRead
value: nil permissions:CBAttributePermissionsReadable];
myCustomCharacteristic =
[[CBMutableCharacteristic alloc] initWithType:myCustomCharacteristicUUID
properties:CBCharacteristicPropertyRead
value: nil permissions:CBAttributePermissionsReadable];
NSArray *myCharacteristics = @[alertLevelCharacteristic, myCustomCharacteristic];
// Now setup the service
myService = [[CBMutableService alloc] initWithType:immediateAlertServiceUUID primary:YES];
// Finally, associate the characteristic with the service. This is an array of characteristics
myService.characteristics = myCharacteristics;
[peripheralManager addService:myService];
... wait for user to push button to start advertising ...
// Start Advertising
[peripheralManager startAdvertising:@{ CBAdvertisementDataLocalNameKey : @"My Service",
CBAdvertisementDataServiceUUIDsKey : @[myService.UUID] }];
And here are the necessary delegate methods. NOTE: delegate method peripheralManagerDidUpdateState fires and indicates that "CoreBluetooth BLE hardware is powered on and ready" (same is true on the central side). Delegate method peripheralManager:didAddService:error fires without error (see output below). And delegate method peripheralManagerDidStartAdvertising:error fires without an error). Here is the service info printed from didAddService:
<CBMutableService: 0x17008efb0 Primary = YES, UUID = 1802, Included Services = (null), Characteristics = (
"<CBMutableCharacteristic: 0x1702c1500 UUID = 2A06, Value = (null), Properties = 0x2, Permissions = 0x1, Descriptors = (null), SubscribedCentrals = (\n)>",
"<CBMutableCharacteristic: 0x1702c15e0 UUID = 66E613B5-7225-42C6-A9C2-11FADAE62899, Value = (null), Properties = 0x2, Permissions = 0x1, Descriptors = (null), SubscribedCentrals = (\n)>")>
CBPeripheralManager Delegate Methods (sorry for all the code, just trying to be complete.):
- (void)peripheralManagerDidUpdateState:(CBPeripheralManager *)peripheral {
// Determine the state of the peripheral
if ([peripheral state] == CBPeripheralManagerStatePoweredOff) {
NSLog(@"CoreBluetooth BLE hardware is powered off");
}
else if ([peripheral state] == CBPeripheralManagerStatePoweredOn) {
NSLog(@"CoreBluetooth BLE hardware is powered on and ready");
}
else if ([peripheral state] == CBPeripheralManagerStateUnauthorized) {
NSLog(@"CoreBluetooth BLE state is unauthorized");
}
else if ([peripheral state] == CBPeripheralManagerStateUnknown) {
NSLog(@"CoreBluetooth BLE state is unknown");
}
else if ([peripheral state] == CBPeripheralManagerStateUnsupported) {
NSLog(@"CoreBluetooth BLE hardware is unsupported on this platform");
}
}
- (void)peripheralManager:(CBPeripheralManager *)peripheral
didAddService:(CBService *)service
error:(NSError *)error {
if (error) {
NSLog(@"Error publishing service: %@", [error localizedDescription]);
return;
}
else {
NSLog(@"Hurray! Your Service has been successfully published as: %@", service);
}
}
- (void)peripheralManagerDidStartAdvertising:(CBPeripheralManager *)peripheral
error:(NSError *)error {
if (error == nil) {
NSLog(@"Your service is now advertising");
}
else {
NSLog(@"In peripheralManagerDidStartAdvertising: Your service advertising failed with error: %@", error);
}
}
And here is the relevant central code that runs on the iPad Mini:
// Scan for all available CoreBluetooth LE devices
NSArray *services = @[[CBUUID UUIDWithString:IMMEDIATE_ALERT_SERVICE_UUID]];
CBCentralManager *centralManager = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
//[centralManager scanForPeripheralsWithServices:services options:nil];
[centralManager scanForPeripheralsWithServices:nil options:nil];
self.centralManager = centralManager;
And here is one of the Central delegate methods. Except for centralManagerDidUpdateState:, none of the delegate methods fire.
// CBPeripheralDelegate - Invoked when you discover the peripheral's available services.
- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error
{
NSLog(@"Did Discover Services");
for (CBService *service in peripheral.services) {
[peripheral discoverCharacteristics:nil forService:service];
}
}
// CBCentralManagerDelegate - This is called with the CBPeripheral class as its main input parameter. This contains most of the information there is to know about a BLE peripheral.
- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI
{
NSLog(@"Did Discover Peripheral");
NSString *localName = [advertisementData objectForKey:CBAdvertisementDataLocalNameKey];
if (![localName isEqual:@"My Service"]) {
// We found the Device
[self.centralManager stopScan];
self.myPeripheral = peripheral;
peripheral.delegate = self;
[self.centralManager connectPeripheral:peripheral options:nil];
}
}
As a final note, I question whether BLE even works on my devices. I loaded a couple different iBeacon apps on the iPhone and iPad Mini to see if I can get the two devices to recognize iBeacons (one transmits, one receives), but they did not discover iBeacons either. I also tried with two iPhones. I also turned Bluetooth off then on. I also tried powering the devices off/on. Both devices are running in the foreground. Still no luck. Please help.
