Cannot find BLE peripheral when scanning for specific services

26 Jun 2012

      When I use:

	CBUUID * uuid = [CBUUID UUIDWithString:@"1800"]; // GAP
        DEBUG_LOG(@"CBUUID: %@",uuid); // CBUUID: Generic Access Profile
        _centralMan = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
        [_centralMan scanForPeripheralsWithServices:[NSArray arrayWithObject:uuid]
                                            options:nil];

I cannot find my peripheral, but when I use:

	_centralMan = [[CBCentralManager alloc] initWithDelegate:self queue:nil];
        [_centralMan scanForPeripheralsWithServices:nil
                                            options:nil];

…it shows up immediately.

When I connect, I am able to discover/read/write to all the services I am expecting. My understanding is that GAP makes this possible. I have also tried CBUUID's for other services that I know are running (specifically "1804", TX power service), to no avail; the scan never discovers anything.

Even though the services are running (I can communicate w/ them upon connecting), when I scan passing the service UUID array as `nil` and this delegate method is called...

-(void)centralManager:(CBCentralManager *)central didDiscoverPeripheral:(CBPeripheral *)peripheral advertisementData:(NSDictionary *)advertisementData RSSI:(NSNumber *)RSSI {
	DEBUG_LOG(@"Found peripheral w/ UUID: %@ RSSI: %@ \n AdvData: %@",peripheral.UUID,RSSI,advertisementData);
	DEBUG_LOG(@"Services found: %d",peripheral.services.count);
	for (CBService * service in peripheral.services) {
		DEBUG_LOG(@"Found service: %@ w/ UUID %@",service, service.UUID);
	}
}

…it always reports "Services found: 0". Should I expect the `services` array to be populated w/ services found during the scan? (I assume this is at least partially possible, based on `scanForPeripheralsWithServices:[NSArray arrayWithObject:uuid]
                                            options:nil`.)

Could this be a problem w/ my peripheral's service advertisements? Am I using the API incorrectly? Any guidance is much appreciated! :-)

--Ben Mosher

PS: I'm pretty green w/ Bluetooth.

PPS: I control the source to the peripheral (it's a CC2540DK). So I'd be as likely to believe the problem is there as it is here.
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Cannot find BLE peripheral when scanning for specific services

Mosher, Ben