I am trying to find a clever way to keep a BLE app active in the background on iOS 6, without breaking any of Apple's rules. I plan to use the phone as a peripheral device and another BLE circuit as the central. My app will automatically be opened when a user arrives to a building using geofencing. After that the iPhone will connect to the first BLE central device it sees (the device will be in its white list). The user will then be able to move throughout the building switching to different BLE "nodes".
My question is: What do I need to do in the background when a user is stationary at their desk so that the app does not get suspended due to memory resources?
My idea is based on this solution for a separate problem: There could potentially (not regularly) be 10-50 users in an area with only a few BLE "nodes" and I read at bluetooth.org that I could setup a dynamic connection system, basically rotating connections through all the users.
My idea is to setup a similar dynamic system where the central device (not the iPhone) disconnects the device on regular intervals (30-40 minutes) and then the iPhone will reconnect.
Is this something that some feasible? Is this against the iOS development guidelines? I was unable to find anything explicit about this. I have also asked on the iOS developer forum, but unfortunately it is not as popular as this site.
Thanks in advance!
Xcode -> Project target -> Capabilities -> Enable background mode
Check Uses Bluetooth LE Accessories
Capabilities
Also enable the following key in .plist file
Required background modes
App communicates using CoreBluetooth
Plist
Related
I'm trying to establish a connection between my PC running Ubuntu and my iPhone via Bluetooth automatically when it becomes available, after being manually paired beforehand. I've seen this to be possible with certain peripherals, mainly audio. For example, my phone will automatically connect to a Bluetooth speaker when it is turned on and Bluetooth is active on my phone; another example is my phone automatically connects to my car's radio system via Bluetooth when I turn the car on.
I'm not able to connect my phone to my PC without first initiating the connection from the smartphone's Bluetooth menu. I'm thinking that I could possibly write an application for the PC to attempt to connect to the device every few minutes or something, but it seems that the phone needs to be the device to initiate the connection.
The only information that I need for what I'm trying to do ultimately is that the devices can pair successfully. Essentially I'm trying to build a sort of proximity trigger between my phone and my PC without using Wi-Fi and GPS - I can't use these for some specific reasons.
Is there any way to make this happen?
Yes this should be doable as long as you use the Background Processing feature for iOS apps. In the example I'll give below, we'll have the PC be the peripheral and the phone be the central, but you can really have it working either way. You will need to do the following:-
First initial connection needs to be performed in the foreground (this is due to iOS's background limitations).
On the iOS side, you need an application that acts as a central that scans and connects to the remove device (check this example as a starting point).
Upon connection, you need to bond with the PC. Bonding is important as it will prevent you from having to do the pairing again in the future. However, pairing/bonding is managed by the iPhone's OS so you cannot write it in your application, so the workaround is to have an encrypted characteristic on the PC side that will force the iPhone to bond (this is covered later).
On the PC side, you need to have a BlueZ script that acts as a peripheral that is always advertising. You can do this using bluetoothctl (check the examples here and here).
Before you start advertising, you need to have a GATT server on the PC side (to do this, check this example).
When registering characteristics, ensure that one of them has the encrypt-read property (you can find a full list of the properties here).
Now when you attempt to read this characteristic from the iOS side, the two devices should bond (make sure that your PC is bondable which you can do this via these commands).
Once the devices are paired, your iOS app needs to be working in the background constantly scanning and attempting to connect to the same peripheral (have a look at this and this example).
You can find more useful information at the links below:-
Getting started with Bluetooth Low Energy
The Ultimate Guide to CoreBluetooth Development
How to manage Bluetooth devices on Linux using bluetoothctl
I am developing an app that controls a product's operation. The communication is via BLE. My configuration is
App - Peripheral (iOS, Android)
Product - Central (uses Laird BT900 module)
iOS as a peripheral works fine (pairing and bonding) ; Android PIN pairing works fine, but subsequent bonding (or reconnect when in range) there are a lot of issues and termination of connection. I am using the supported list of devices for Android BLE and I also understand that there are many known issues that come with different manufacturers/chipset vendors
The issue I am getting is, as seen by nrfConnect, is with descriptors. Android app doesnt show descriptors when seen in nrfConnect whereas iOS shows. I do not know what is the difference
Is it a common practice to use a phone as a peripheral ? Or is it a risk - because this is a medical device.
Are there any best practices for Android as a peripheral ?
I have following back up plans in case Android issue is not resolved. I think following would work on any BLE supported phones without having any issues with the variability.
Plan A : PIN pairing on every connection with the product. This is the most secure and most annoying
Plan B : Implement just works pairing with a app layer password before taking control of the product.
Question : Is just works safe and encrypted ? Is it snoop-safe or MITM-safe ?
Thanks in advance!
A few thoughts from your questions:
1a. (From my Android experience) I think its uncommon to have the phone be the peripheral. To my knowledge all iOS devices support peripheral mode but only a very small subset of Android devices are able to support it. I say this because I've been experimenting with BTLE beacons using the AltBeacon library. From this work I have discovered that only certain Android phones can broadcast BTLE advertise packets. Given that BTLE advertising is the first step in initiating a BTLE session I imagine that this prevents many Android phones from being compatible with peripheral mode.
If all of your users can use an iOS device, then you're set, otherwise this may be a problem.
1b) I can't speak to the specific risk of using a mobile device with your medical device, that depends on what the medical device is doing and how you're using the mobile app.
2) See 1a
3) The specific encryption scheme you used is also based on your product's risk profile. I would say that Just Works is not an ideal solution. The just works pairing process is not snoop-safe and can be re-initiated via a MITM. Other than that I can't speak to the strength of BTLE encryption.
I work with POS devices. We have a cross-platform mobile Xamarin App which talks to POS devices using Bluetooth or USB.It would be a great help if you can do that.
No you cannot, unfortunately the only way to interact with any device needed by the mobile client is through web requests. Unfortunately this is limited because no 1 BLE solution would work for everyone (actually it would only work for very few).
Another challenge is that the automated UI tests will run in the order determined by Xamarin Test Cloud and you may potentially have multiple devices interacting with your one device.
You could do this all locally though on your own device. You would just trigger the UITest locally through the command line and have the BLE device by your phone. I know this isn't ideal, but really one of your best options here.
The other option you have is creating a middle-man for your POS devices. Basically the middleman would be a REST API hosted on some IoT device that contains BLE integration. You would than have to forward the BLE requests from the IoT device to your POS device, but this solution would require larger time frames for the data to transfer and wouldn't necessarily be a "real-world" testing scenario. I would expect that you would have some false failure tests due to the details with creating this solution. I have done something similar for Particle, but I was only able to run UI Tests on 1 device at a time.
Disclosure: I work for Xamarin/Microsoft.
I want to be able to pair Microsoft PixelSense hardware with multiple mobile devices via bluetooth and I want PixelSense to know which device is which. So if I place two phones on a table, PixelSense should be able to label them by device name. My initial thought was to have the phone display an Identity Tag that has encoded its Bluetooth MAC address so that it could associate them but PixelSense sees in infrared and can't read the phone screen so that idea is out. Can anyone think of another way to do this?
Microsoft has demonstrated a way to do this in their Mobile Connect sample application. They've ingeniously used the fact that almost all phones have a camera that faces down when the phone is placed on a flat surface. So they created an app that will read incoming color data from Surface while the phone is sitting on it.
So it goes like this:
The Surface app starts and makes the Surface computer itself visible on bluetooth (although you may have to do this manually in admin mode, can't remember)
you run the mobile app on your phone, click connect, and place it on the Surface at a designated spot
the Surface flashes a serious of colors into the phone's camera
the phone decodes those colors into a pin and scans through all the open bluetooth devices it can see until it finds one that is a desktop running the appropriate service and accepts the decoded pin.
Now the two are connected with no need for manual input and the Surface knows which physical device it's talking to because it knows which pin it displayed to each device.
*Note - They don't actually allow multiple simultaneous connections in this sample app, but I see no reason why it wouldn't work.
One issue with this approach (other than being pretty complicated to code), is the need for the app on the phone. One way to make it easier for people to get the app is to display a Microsoft Tag or qrcode on the Surface for people to scan (they're much more likely to have a scanning app already). I don't think there's any getting around the need to have something installed on the phone if you're using bluetooth anyway.
I am writing a windows application (written entirely in C++) which reads files from a storage card on a mobile phone running Windows Mobile. The tough part is, I don't know how to make my application detect the event that a user has connected the mobile phone to the USB of laptop. I did some reading on MSDN and have written a small code using RegisterDeviceNotification, which detects whenever a USB disk is attached/removed from the laptop. However, I am unable to tweak this to make it work for phone type devices. Please help me out through any links/tutroials which explains this(preferrably C++, as I don't know .NET or C#).
Thanks
Alok
According to this article you can use RegisterDeviceNotification to get notifications when activesync detects a device has been plugged/unplugged. (See option 3 at the end of the article)
It may just be a matter of setting up the correct notification filter.
Windows Mobile devices use RNDIS, a network interface protocol behind the scenes. Hence, the RegisterDeviceNotification method still works, but you're looking for a DEV_BROADCAST_DEVICEINTERFACE, not DEV_BROADCAST_VOLUME. (i.e. dbch_devicetype==DBT_DEVTYP_DEVICEINTERFACE)
You can use RAPI or RAPI2 to detect when a Windows Mobile device connects to a PC via Active Sync or Windows Mobile Device Center. RAPI can also be used to read the files on the storage card and much more.
RAPI is simpler to program because it is a C based API. RAPI2 has more functionality than RAPI, but is an object oriented COM API. If your needs are simple and you only care about one device/connection at a time then RAPI is good enough. There are two RAPI functions used to detect connections: CeRapiInit (blocking), and CeRapiInitEx (signals an event upon connection).