I have been exploring CoreBluetooth and BLE connections between OS X and iOS, where I've discovered an interesting problem. I have the Mac implementing CoreBluetooth central and iOS implementing CoreBluetooth peripheral. Since iOS no longer broadcasts a constant, consistent MAC address or other identifier, there is no reliable way (that I can find) to allow the Mac to connect to the iOS peripheral whenever it is in range, including when the iOS app is running in the background.
By storing the last connected peripheral, I can get OS X to constantly search for the iOS device like shown:
[central connectPeripheral:self.lastPeripheral options:nil];
Which works if self.lastPeripheral was previously connected to the OS X client. This initial connection can only be created if the iOS app is open at the time; it will not work if it is backgrounded. This in itself is not a horrible issue, but every single time the OS X app quits, this connection must be reinstated by opening the iOS app.
Is there any way to connect and reconnect (when the device moves back into range) via BLE to an iOS device when the iOS application is backgrounded, especially to persist between app launches?
BluetoothLE is still a energy consuming technology. And Apple goes into great lengths to limit its "active" usage on iOS, in situation they don't deem as correct (e.g. background). That said, there are no guaranties on for how long a iOS device in peripheral mode continues to advertise (pre-requirement for reconnection).
Did you think about switching the roles. Making the OS X machine the peripheral, and the iOS device the central? I know from experience that iOS behaves much nicer when acting as a central.
Related
I'm trying to discover a bluetooth device from an iOS app I developed. The device is an industrial sensor which send a measure every x ms.
I dont understand why I can see and connect to the device from my MacBook but not from my iPhone. The device is not visible in iPhone bluetooth settings. I dont find it through CoreBluetooth too (by using 'scanForPeripheral' method). Is there particular specifications on iOS?
I'm allowed to setup every data I want on the BT device (profil, CoD, UUID, etc.)
The iOS app is basic and simple. I'm using CoreBluetooth framework.
I have an iOS and macOS app that make heavy use of Core Bluetooth. The core functionality of the app involves having a central device (CBCentralManager) connect to a peripheral device (CBPeripheralManager), retrieve some data, then disconnect. Either device, whether macOS or iOS can act as either a central or peripheral depending on who needs the data.
At first I thought there was an issue with my code, but after testing the app with two iOS devices, one is able to connect and extract data from the peripheral device even when the peripheral device is locked and the app is in the background. Now according to the docs concerning background advertising on iOS under "The bluetooth-peripheral Background Execution Mode" this is kind of expected:
...they can be discovered only by an iOS device that is explicitly scanning for them.
Is there any way to have a macOS app discover peripherals even when they're backgrounded? I'm sure the code I've written is correct because it's the same across iOS and macOS.
Update 1
I believe that this might be possible just unsure how to approach the issue. Using Apple's Bluetooth Explorer on macOS, I am able to find the desired device AND I'm able to see and read data for my custom service.
This finding is validated from logs from my iOS device about the read requests which are from my peripheralManager(CBPeripheralManager, didReceiveRead: CBATTRequest).
I'm developing an application on iOS and OS X Yosemite which is using CoreBluetooth on iOS and IOBluetooth on Mac.
The iOS app plays the "central" role while the Mac app is playing the "peripheral" role.
Basically, the iOS app (the central) starts a scan to find peripherals and when it finds a Mac advertising peripherals data, the central connects to it and can discover its services and characteristics.
My problem is that sometimes, I don't know why, the iOS app starts a scan to find a Mac advertising and when it finds it (this step work all the time), it tries to connect to it but never succeed.
To make it able to connect successfully to the peripheral again, I need to turn off and then turn on the Bluetooth from the iOS button.
Another strange thing is : imagine the central is in the same situation (trying to connect with no success). On OS X if I click on the Network icon (with the Wifi symbol) in the system status bar, then it will display the list of all available Wifi networks, and when it adds to the list my iPhone as a "Personal hotspot", at this time the central (which is on the iPhone) manages to connect to the peripheral (the Mac).
With this problem, the app usage is a lot compromised because randomly the iPhone will not be able to connect to the Mac.
I spent a lot of days on the internet (Google, Stackoverflow, ...) to find similar cases. I read a lot of articles and tried a lot of things like stopping the scan and starting it again if the connection didn't succeed after 10 seconds for example.
Don't hesitate to tell me if my question is not clear. I will update it if needed.
Thanks a lot in advance for your help.
I really need to find a way to fix this.
I don't have an answer (and not enough rep to comment) but I have been experiencing a very similar problem for months now. My iOS app which is playing the central role sometimes fails to discover services on the peripheral (linux) which can only be fixed by power cycling the bluetooth radio on my iOS device via settings/bluetooth. After bouncing the bluetooth radio, peripheral discovery appears to works perfectly.
I've found two reproducible cases: (1) If on my peripheral I completely swap out the service being advertised (i.e. change the service UUID and all characteristics) then the iOS peripheral will detect the peripheral with this new service during the scan, but service discovery fails. I find that peripheral:didDiscoverServices gets invoked, but the list of services is empty for this peripheral. (2) If on my peripheral, I modify the list of characteristics in any way (add a new one, remove one) the iOS app does not notice this change at all. During characteristics discovery, the same list of characteristics (prior to modification) is presented. Again, power-cycling the bluetooth radio on the iOS device appears to be the only thing that fixes this.
It appears as though iOS is caching BTLE peripheral services and characteristics upon discovering a new peripheral and the only way to flush this cache is to power cycle the bluetooth radio.
My objective here is to create a connection between a device running iOS to a device running Mac OS X, via bluetooth. I know that I might be able to use CoreBluetooth for this but I don't understand how since I don't see a method to setup a service on the iOS device and broadcast it as an available service for a device running Mac OS X. In other words, I simply want to setup a connection to get the iOS device to send data to the Mac OS X device. Also, how would I go about to specify how to setup properties of the service. I've tried researching this stuff but most of the documentation makes little sense to me. The data transfer is small so bluetooth is good enough for the job. I'm trying to avoid Bonjour for this, and the Game center framework for P2P since OS X can't handle that (I think).
In iOS6 the iPhone 4S, 5 and New iPad can work both as Peripheral and as Central in Bluetooth Smart / Low Energy mode.
Try downloading "LightBlue" APP from APP Store. It let's you put the iPhone4S or 5 into Peripheral mode with random Services which you can then read from the Mac (if you have a newer one with BT Low Energy, I use the Retina for that but also the new iMac and Mac Mini got BT Low Energy).
You are correct that Core Bluetooth only give access to Bluetooth Low Energy which doesn't allow for the MFI chip.
Just ran across this today... and just wanted to give another answer to anyone needing to communicate to a non-Bluetooth LE device from your Mac.
The way to go is with IOBluetooth, and IOBluetoothUI.
They are both frameworks for the Mac, and they allow you to communicate with both old bluetooth, and Bluetooth LE 4.0, I believe. Also, I'm pretty positive you can act as a Central and Peripheral Device using this framework.
Is is possible to "pair" a Bluetooth BLE device such that they automatically connect when in range? (ie. an iPhone app sets up a connection to the Bluetooth device and from then on, the iPhone automatically reconnects to the device if in range, even if the app hasn't been opened in days and is fully closed).
Once reconnected, the device could either using Event Backgrounding to prompt the user to open the app or otherwise interact with a possibly backgrounded app (as described here).
Anecdotally, I've used Bluetooth keyboards that automatically reconnect to my laptop when back in range. These are not necessarily BLE devices, is this something that's possible in BLE land?
Could this be possible if the iPhone were the server instead of the device? What if this were done using traditional Bluetooth under the MFI program?
There are number of relevant comments here and on the Apple Bluetooth-dev mailing list, but nothing that cleared it up for me. Thank you for your help.
I posted my question on Bluetooth-dev, I'm leaving the response here for posteriority: http://lists.apple.com/archives/bluetooth-dev/2012/Sep/msg00117.html