Bluetooth: Connecting without UUID - android

Yesterday i learned that i need to know the UUID of the Device which i want to connect with but that leaded to some questions i could not answer myself and i could not found it in the web either.
If i connect two devices which are running the same Software or App or anything else it is easy to hardcode those UUID's but what if it is not the same Software or the same App? For example if i transfer contact data from my Android Phone to a friends Apple iPhone, how could my Android Phone know the UUID of the iPhone?
Another example would be my Bluetooth-Headphones. I never installed any Software or any App on my Device but after the Bluetooth-Pairing my Headphones are working. How could my Headphones know the UUID of my Android phone?

Okay, got it: Service Discovery Protocol (SDP)
There are several fix UUID's that can be used for different services.
So what i have to do for my purpose is just to use my own UUID on
each device.

Related

Bluetooth-know which devices have my app installed while searching

I am developing a client-server bluetooth chat app where multiple clients can connect with the server. If I have multiple servers, I want the client the choose which server it can connect nearby to but I am having problems in knowing which device has the app installed and it is a server. There are multiple bluetooth profiles and I am not sure which one to use it and how. Pre-Storing the MAC id's of the devices with server is one solution but I don't want to do that. Please suggest something. Thanks a lot :)
I assume the intention is to avoid an insecure connection attempt with listenUsingInsecureRfcommWithServiceRecord/createInsecureRfcommSocketToServiceRecord(1).
If you don't mind changing friendly name of the device, just during the device discovery period, you can rename your servers to a pattern of yours with setName(2). On device discovery, you can get the remote device name(3), followed by pattern matching before initiating the connection.
And revert the name, once you are done with discovery.
You use a UUID to create the BluetoothServerSocket. This UUID identifies YOUR application and is retrievable by the bluetooth discovery. This UUID is used to connect to your server device as well so you don't need to encode your app's name in the service name.
Check this answer for a detailed description:
How do Bluetooth SDP and UUIDs work? (specifically for Android)

Android discovering same app UUID devices

I am using bluetooth adapter to discover bluetooth devices. The search displays all devices (iOS , Android, Speakers etc) which are available in surrounding with Bluetooth turned ON.
My App sends and receive data, so installed on two different Android Devices, app can perform a chat functionality, provided both apps are using same App UUID.
Is it possible that when I perform the device discovery/search, I only limit discovery to those devices which are Android and are using my App i.e. my App UUID and not to show all other bluetooth devices.
I know this happens in iOS using characteristic UUID.
Appreciate Response.
1) First you're doing an Inquiry (search) of all nearby devices
2) for each device enumerated, do a Discovery (SDP) on it to gather all its services/profiles; If you found the one you're searchnign for, display it, otherwise forget it...
PS: I have no idea about selecting Android devices only... You can use the CoD (Class Of Device) but not sure that you can separate Android from other "smartphones"...

Bluetooth pairing without pin code

I am a newbie working on bluetooth, and I would like to get some advice regarding the pairing process. I have googled this but I did not find much information ...
My goal is simple: I want to do a pairing to a headset without entering a pin. I have an android (nexus S running Android 4.1.2) and an iphone (3GS running ios 6.1.3).
If I connect to a device like a Jabra BT3030 (bluetooth headset), the pairing is performed without asking me any pin code.
Now I want to do the same from an Ubuntu (with BlueZ 4.6), i.e. I fake a bluetooth headset by enable only the correct service and so on. I disabled the authentication.
When I pair my iphone to this device, no pin code is required (as expected), but when I connect from my Android device, it still asks me for a pin code, whereas I would expect to have the same behavior than with the Jabra.
Would you have any idea of what I am missing here?
Thanks in advance,
Best regards,
Guillaume
Android Uses UUID for pairing and connection for two devices...for two devices conneting, one device should send request and one should accept and for both UUID should be same...
Like also used bluetooth there I need to intall my android app to both the devices then only I can pair the two devices...because only that app is knowing the UUID. and for iPhone it may be different so if from the native code of iOS u can know the UUID ur android device can be paired through app...
The Standard password for a Jabra BT3030 is 0000. Many other bluetooth devices have a standard password. For the Case a system only accepts devices with passwords, and u cant enter a pasword on a device without keys :D
Maybe the solution is implementing the standard passwords for mutliple devices and use them instead f forcing a connection without password.

How to send Bluetooth data to an unknown device?

I'm asking because I've been facing that issue for weeks.
I need to develop an Android application that can be able to perform an Bluetooth Connection and send data to an Bluetooth Hardware.
Ok, so here's the point:
is it possible to perform a RFCOMM connection to an 'unknown' device?
I mean, is it possible to do this without having any information about the hardware code?
Because i'm only able to modify the AndroidDevice (cellphone) code, for SENDING purposes.
I want to send a byte and make sure it was received, but there's only a sending code.
Could we have some more details? Is the other device accessible by you, as in can the other device know information about the Android device? And what do you mean by a "sending code"?
The Android device can pick up any active Bluetooth device in its range, and know the name and address of those devices. So, if the Android device doesn't know anything about the Bluetooth device it wants to connect to, you can always sort through the list of devices in range, and get its hardware code through that.
See the documentation about Bluetooth, specifically the Finding Devices section:
http://developer.android.com/guide/topics/connectivity/bluetooth.html
I've done a fair amount of Bluetooth work with Android devices and Arduinos, and the Bluetooth library might be a bit of a pain to work with, but it is powerful.
With bluetooth the two devices have a UUID. If you a writing a program that runs on both devices you have them listen for that UUID. When they connect as a client or a server you have a dataInputStream and a dataOutputStream. Then you can push and pull bytes out of those.

Doesn't search any discoverable devices

Can any one describe what is wrong with this code. It didn't search devices, and it showed some paired devices.
Project hosted here in Github.
think of the UUID as one identifier for a particular kind of service your device is advertising or accepting. It could have many such identifiers for many different services it can offer or use. It's not an identifier for the actual device.
The UUID you are quoting is the same one I found here and use too. it seems to be the UUID for generic bluetooth SPP service. (but haven't found much actual proof like an official published document quot8ing this number, just posts on here with no refrence) This UUID will allow your android device to connect to things like bluetooth serial port adapters, or anything expecting a generic serial port device... so it's a good one to start with.
If you plan to create a special service that's not the same as bluetooth SPP or has a different reason to exist, like android chat does, then it's a good idea to create your own UUID. Of course all devices to connect your service will have to understand this same special number.

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