Not able to recognize the beacon using CBPeripheral in iOS

Question

Edited: Removed iBeacon code. Since there is not issue with iBeacon code.

-> Once we recognize our beacons, we have to communicate with the first beacon using BLE. We are using Bleno framework on Respberry PI.

//Passing my service UUID

[bluetoothManager scanForPeripheralsWithServices:@[@"87fa7df2-748c-4093-8e73-b93ee73543b4"] options:scanOptions];

Issue is, If we pass my service UUID (validated with Light Blue App), I am not getting any results. Instead, If we pass "nil", I am at least able to recognize my device.

So, Is there any generic way to recognize our Bluetooth device from iOS Code. Since CBPeripheral is returning limited properties.

<CBPeripheral: 0x1700ff700, identifier = 7915DCF8-AF2E-4AF2-B5FC-A5EEA10D3812, name = raspberrypi, state = connected>

I tried to change my bluetooth device name using below command using BLENO framework.

sudo BLENO_DEVICE_NAME="SOME_NAME_86" node iBeacon.js

Sometimes, I am able to read the name. But not all the times. So I am looking for alternative solution.

Here is my code:

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.    
    _centralManager = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
    _data = [[NSMutableData alloc] init];
}


- (void)centralManagerDidUpdateState:(CBCentralManager *)central {    
    switch (central.state) {            
        case CBManagerStatePoweredOn:
[_centralManager scanForPeripheralsWithServices:@[[CBUUID 
UUIDWithString:@"87FA7DF2-748C-4093-8E73-B93EE73543B4"]] options:@{CBCentralManagerScanOptionAllowDuplicatesKey : @YES}];                break;            
        default:            break;
    }
}


- (void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI {

    if (_discoveredPeripheral != peripheral) {
        _discoveredPeripheral = peripheral;
        [_centralManager connectPeripheral:peripheral options:nil];
        [_centralManager stopScan];
    }
}

- (void)centralManager:(CBCentralManager *)central didFailToConnectPeripheral:(CBPeripheral *)peripheral error:(NSError *)error {
    NSLog(@"Failed to connect");
    [self cleanup];
}

- (void)cleanup {

    // See if we are subscribed to a characteristic on the peripheral
    if (_discoveredPeripheral.services != nil) {
        for (CBService *service in _discoveredPeripheral.services) {
            if (service.characteristics != nil) {
                for (CBCharacteristic *characteristic in service.characteristics) {
                    if ([characteristic.UUID isEqual:[CBUUID UUIDWithString:TRANSFER_CHARACTERISTIC_UUID]]) {
                        if (characteristic.isNotifying) {
                            [_discoveredPeripheral setNotifyValue:NO forCharacteristic:characteristic];
                            return;
                        }
                    }
                }
            }
        }
    }

    [_centralManager cancelPeripheralConnection:_discoveredPeripheral];
}


- (void)centralManager:(CBCentralManager *)central didConnectPeripheral:(CBPeripheral *)peripheral {
    NSLog(@"Connected");

    [_centralManager stopScan];
    NSLog(@"Scanning stopped");

    [_data setLength:0];

    peripheral.delegate = self;    
    [peripheral discoverServices:@[[CBUUID UUIDWithString:@"87FA7DF2-748C-4093-8E73-B93EE73543B4"]]];
}


- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error {
    if (error) {
        [self cleanup];
        return;
    }

    for (CBService *service in peripheral.services) {
        [peripheral discoverCharacteristics:@[[CBUUID UUIDWithString:TRANSFER_CHARACTERISTIC_UUID]] forService:service];
    }
    // Discover other characteristics
}

- (void)peripheral:(CBPeripheral *)peripheral didUpdateValueForCharacteristic:(CBCharacteristic *)characteristic error:(NSError *)error {
    if (error) {
        NSLog(@"Error");
        return;
    }

    NSString *stringFromData = [[NSString alloc] initWithData:characteristic.value encoding:NSUTF8StringEncoding];

    if ([stringFromData isEqualToString:@"EOM"]) {        
        [peripheral setNotifyValue:NO forCharacteristic:characteristic];        
        [_centralManager cancelPeripheralConnection:peripheral];
    }

    [_data appendData:characteristic.value];
}

@end

Problem is, I have two Bluetooth devices side by side, advertising same service ID. Based on scenario, I should connect to only one device & read their characteristics.

Answer 1

If you are trying to detect and communicate with an iBeacon from iOS, you most likely want to use Core Location, not Core Bluetooth...

Take a look here: https://developer.apple.com/reference/corelocation?language=objc

Edit: I haven't run this code, but after a quick browse of the code, it looks like a decent example of scanning for and detecting iBeacons: https://github.com/ThomasJay/Locate

Answer 2

The array you send to scanForPeripheralsWithServices is an array of CBUUID objects, not an array of strings. You need:

[_centralManager scanForPeripheralsWithServices:@[[CBUUID UUIDWithString:@"87FA7DF2-748C-4093-8E73-B93EE73543B4"]] options:nil];

Answer 3

Stumbled this by accident and this seems stale, but since I was in similar situation (and spent a day or so figuring this out) decided I will answer this for anyone reading this in the future. Most likely you have services running, but you are not broadcasting their availability. That way, your services are only visible after pairing to the device.

To test that, scan with nil value for services and print the contents of the advData array available in centralManager:didDiscoverPeripheral:advertisementData:RSSI:. If your service UUID is not available in that dictionary (under key CBAdvertisementDataServiceUUIDsKey), there's no way for iOS device to know that service is available without pairing.