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.
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Since the latest update (I think some time in December 2022), the built-in camera app on my Samsung Galaxy S21 asks for "Nearby devices" permission, and refuses to run if I don't grant it. By "Nearby devices" it means "Bluetooth". I don't know why it calls the permission
"Nearby devices": all other references to Bluetooth call it "Bluetooth",
and you can also access a nearby device using Wi-Fi or even NFC if the device
is close enough.
It doesn't actually need Bluetooth to take photographs, or even to record movies,
but you might have a Bluetooth microphone (I don't) and you might want to use
it to get better sound quality when recording a movie.
Of course the Android best practice advice at
https://developer.android.com/guide/topics/permissions/overview
is not to ask for runtime permissions unless and until you need them,
but Samsung aren't doing that.
I don't want the camera app to announce my presence by probing the Bluetooth headset of
anyone who happens to be near me, and they might regard such an action as intrusive.
So I don't want to give the camera app its nearby devices permission, but it won't
run at all without it.
So how do I get the camera app to run without accessing Bluetooth?
I found some workarounds for this. If your device supports it, you can download Expert Raw from the Galaxy Store. This will take still photos without requiring "Nearby devices" permission. However it doesn't seem to be able to do selfies because there seems to be no way to switch cameras, and it can't do movies or many of the extra tricks that the full camera app can do.
Another option is to run the camera app with Bluetooth disabled. Then it can have its "Nearby devices" permission, but it can't use it. The problem with this is that if you use Bluetooth at other times you have to remember to disable it and enable it.
So I wrote a tiny app which disables Bluetooth, runs the camera app, and restores the previous enabled or disabled state of Bluetooth when the camera app exits. I put this on my home screen instead of the camera app: it has the same icon. You have to remember to exit properly from the camera app using the Back button: the Home or Recents buttons leave my app and the camera app sitting on the task's back stack, so my app doesn't get to run and restore the Bluetooth state.
The app is available on github here in case anyone else wants to use this solution.
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'm working on a project to track delivery trucks leaving and returning to the office.
While I know RFID would work, we're also looking at BlueTooth with mobile apps. Ideally, once a driver installs the app, we register a unique ID for the device, and a BT reader identifies when phones/deliveries leave and enter range without any user interaction.
From the Android 6.0 release notes, it looks like the MAC address is hidden from apps and BT broadcasting. https://developer.android.com/about/versions/marshmallow/android-6.0-changes#behavior-hardware-id
User management of app installs and enabling BT aside, is this feasible?
Can someone point me in the right direction to confirm what identifiers are available?
When I understand you correctly you actually do not want to track where a phone is but want to know if a person/truck/phone passes a kind of checkpoint or gate?
For newer smart phones you cannot rely on the visible MAC. Bluetooth classic is usually not visible and the BLE MAC is randomized as long as the device is not paired and bonded.
Indeed as PaulW11 stated, the simple way would be to implement an app which does BLE advertising with short advertising interval. Inside this advertisment you can put some custom data. This will be visible to everyone. This ID can be some random number, a number assigned by you or whatever.
At the gate you would implement a BLE scanner grabbing all advertisments near to it.
This should be easy to implement.
I would also like to mention the drawbacks here: If someone passes the gate you may miss him. BLE with Android is always tricky and you might have the situation that the bluetooth subsystem on a phone may have stopped working or so.
One the other hand if someone comes accidently near to your gate, you will think he left or returned. Near can be something around 50 m or so with good conditions or only 10 in other cases.
And even worse: If someone stays 'nearly' in the range of the gate you will see im sporadically. This may confuse your come and go logic if he is visible every 3 minutes or so...
I'm currently working on a project for an interactive visitor centre in Laguna Beach, CA.
There are many touchscreen devices around the space, which we are developing some cool software for, however one of the client requests is to allow visitors to transfer image, pdf and video files from an interactive coffee table touchscreen onto their phone.
The client has seen this on YouTube/CES etc.. You know, where someone puts a phone on a the interactive surface and then magically swipes images onto the phone from the screen.
Of course, if the visitor had a custom app on their phone, and was already on the same WiFi this would not be so much of a problem. I suspect this is what happens on these magic demos that we see.
In our situation, we don't want the visitor to download an app really, we just want the easiest solution and experience for the visitor. We have a public WiFi available to us, and we can install an NFC device on the touchscreen and the touchscreen also has bluetooth.
My ideal scenario would be for the user to pop their NFC enabled phone on the table, the table recognises it, pairs with BT or WiFi and away we go! I'm not sure how practical this is though having researched around. Clearly thats not going to work on an iPhone. I don't mind a couple of mechanisms i.e. one for Android/other NFC phones and one for iPhone.
Does anyone have any experience of this kind of thing and suggestions of how to handle it?!
Here's a mock up of our 32" Coffee Table touchscreen just for some context
Thanks for reading through and having a think :-)
I know that there is standardized way to pair Bluetooth device using NFC tag. I think this is the best solution for you. The authority that is standardizing this format is called NFC Forum. You can find more info about the topic in this document: Bluetooth Secure Simple Pairing Using NFC
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