蓝牙外围设备不应答

Question

I am in big trouble with my exams. I have to write an iOS app that uses an external sensor made by Texas Instruments, it's called TI Sensortag . TI's documentation, in my humble opinion, is really poor and complicated to understand for an entry level programmer. I tried to ask in the E2E forum but they weren't able to help me, their answer was something like "Um, well, we don't know, go away and ask someone else", ...

I added the CoreBluetooth framework to my project an created a CentralManager. I am able to find my device, connect and get his name and (sometimes) his RSSI. Now what I'm trying to do is to ask my CBPeripheral object if it has some services for me or something like that. I've found the Complete Attribute Table but I have no idea how to use it... I know I have to activate some services or something like that but I really don't now ho to do it, I googled a lot but I've not found something helpful...

I'm trying to enable my sensor with this method, but I'm doing something wrong.

-(void) configureSensorTag
{

    uint8_t myData = 0x01;

    NSData *data = [[NSData alloc] initWithBytes:&myData length:1];

    [BLEUtility writeCharacteristic:myPer sUUID:@"F000AA00-0451-4000-B000-000000000000" cUUID:@"F000AA02-0451-4000-B000-000000000000" data:data];

    [BLEUtility setNotificationForCharacteristic:myPer sUUID:@"F000AA00-0451-4000-B000-000000000000" cUUID:@"F000AA01-0451-4000-B000-000000000000" enable:YES];


    NSLog(@"Configured TI SensorTag IR Termometer Service profile");

}

Moreover I'm trying to retrive Sensortag's services with this method

[peripheral discoverServices:nil];

and his delegate

- (void)peripheral:(CBPeripheral *)peripheral didDiscoverServices:(NSError *)error
{
    NSLog(@"Found service");
    if (error) {
        NSLog(@"Error: %@", error);
    }

}

but it is never called.

Has someone any idea?

Thank you very much!

Answer 1

Unfortunately I can't help you with the details of the iOS, but I can help you with understanding the sensor tag. If you look at that attribute PDF you linked you'll find entries marked "GATT_CLIENT_CHAR_CFG_UUID". It's 16 bits of flags where only the 2 least significant bits are used. It even says in there 'Write "01:00" to enable notifications, "00:00" to disable'. (That's the least significant bit because it's encoded in little-endian format)

So, you're sending a 0x01 to turn on the IR temperature sensor, but you haven't turned on the notifications. Turning it on will then cause the device to stream notifications back to the client. The accelerometer doesn't require turning on, so maybe you should try that first.

I have no idea what that second chunk of code is supposed to be doing... sorry.

Answer 2

Ok ok I got it, there were any software problem, I mean, not by iOS side. Sensortag has a wrong firmware and so it did'n work.

I've changed Sensortag and now everything works fine.

Thank you anyway!