Android bluetooth one to many

Multiple bluetooth connection

I want to connect 3 devices via bluetooth (My Droid must connect to 2 bluetooth devices). I ‘ve connected my Droid to 1 device using Bluetooth chat. How should I modify it for multiple bluetooth devices?

8 Answers 8

I was searching a way to connect 4 devices with bluetooth and I found the following.

I’m not sure that this is what you want.

But in order to connect more than 2 devices using bluetooth you have to create a different UUID for each device you want to connect.

Follow the link to see code examples and a better explanation.

You can try my lib for multiple bluetooth connection :

Hey @Rami, Can you check this issue stackoverflow.com/questions/46927973/… , it’s a kinda problem with the git project what u posted

Have you looked into the BluetoothAdapter Android class? You set up one device as a server and the other as a client. It may be possible (although I haven’t looked into it myself) to connect multiple clients to the server.

I have had success connecting a BlueTooth audio device to a phone while it also had this BluetoothAdapter connection to another phone, but I haven’t tried with three phones. At least this tells me that the Bluetooth radio can tolerate multiple simultaneous connections 🙂

Using the Bluetooth APIs, an Android application can perform the following:

• Scan for other Bluetooth devices
• Query the local Bluetooth adapter for paired Bluetooth devices
• Establish RFCOMM channels
• Connect to other devices through service discovery
• Transfer data to and from other devices
• Manage multiple connections

Two UE Boom Bluetooth speakers can form a stereo, which means the phone can stream simultaneously to two Bluetooth devices. The reason is Bluetooth 4.0 can support up to two synchronous connection oriented (SCO) links on the same piconet, and A2DP is based on SCO link.

Your demand «bluetooth chat» is based on SPP profile, and SPP is based on RFCOMM protocol. Luckily even Bluetooth 2.1 can support multiple RFCOMM channels, so yes, you can have multiple bluetooth connection to chat with each other.

Yes, your device can simultaneously connect to 7 other Bluetooth devices at the same time, in theory. Such a connection is called a piconet. A more complex connection pattern is the scatternet.

The reason it is limited to 7 other devices is because the assigned bit field for LT_ADDR in L2CAP protocol is only 3.

You can take a look here ( this is not a solution but the idea is here)

what you have to change/do :

• separate server and client logique in different classes
• for the client you need an object to manage one connect thread and on connected thread
• for the server you need an object to manage one listening thread per client, and one connected thread per client
• the server open a listening thread on each UUID (one per client)
• each client try to connect to each uuid (the uuid already taken will fail the connection => first come first served)

Not exactly true — take a look at the specs summary

Logical link control and adaptation protocol (L2CAP)

L2CAP is used within the Bluetooth protocol stack. It passes packets to either the Host Controller Interface (HCI) or on a hostless system, directly to the Link Manager/ACL link. L2CAP’s functions include:

• Multiplexing data between different higher layer protocols.
• Segmentation and reassembly of packets.
• Providing one-way transmission management of multicast data to a group of other Bluetooth devices.
• Quality of service (QoS) management for higher layer protocols.

L2CAP is used to communicate over the host ACL link. Its connection is established after the ACL link has been set up.

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Bluetooth on android — Is it possible to connect to more than one bluetooth device at the same time?

Bluetooth uses the connect function to connect to a target Bluetooth device, using a previously created Bluetooth socket. The name parameter of the connect function, which is a SOCKADDR_BTH structure, must specify a target Bluetooth device.

Bluetooth on android — Is it possible to connect to more than one bluetooth device at the same time?

I am trying to connect to more than 1 bluetooth device at the same time, But I am getting the next error:

java.io.IOException: Host is down 

at the second time I am trying to connect :

 private final BluetoothSocket mmSocket; mmSocket.connect(); 

Is it possible to connect to more than one Bluetooth device at the same time?

Yep, normally up to 8 devices can exist in a (what’s called) piconet. Basically one master may communicate with up to 7 other devices. That’s how the Bluetooth protocol is specified.

Can you establish multiple Bluetooth connections, AFAIK, multiple connectivity is not possible in case of Bluetooth Connection. Bluetooth is Connectivity API is by default Synchronized so only one connection at a time is possible. So you can not perform multiple connections.

How to switch the Bluetooth pairing connection to a

Instructions on how to switch the Bluetooth pairing connection when using multiple Bluetooth devices .

How to Connect Multiple Bluetooth Headphones to ONE

This product has since been discontinued (July 2020), please see our newest solution for «multiple headphones one source»: https:// youtu.be /bwRXatrQ1mwLearn

Can a Bluetooth Headset Connect to More than One

It’s not just Bluetooth, it charges by USB. It’s a proprietary connector, but it comes with the cable. The nice thing is that you can pair this one headset with up to five devices. You can use it

Bluetooth and connect

Bluetooth uses the connect function to connect to a target Bluetooth device, using a previously created Bluetooth socket. The name parameter of the connect function, which is a SOCKADDR_BTH structure, must specify a target Bluetooth device. Two mechanisms are used to identify the target device:

• The SOCKADDR_BTH structure can directly specify the port number to which a connect is requested. This mechanism requires the application to perform its own SDP queries prior to attempting a connect operation.
• The SOCKADDR_BTH structure can specify the unique service class ID of the service to which it wants to connect. If the peer device has more than one port that corresponds to the service class ID, the connect function call connects to the first valid service. This mechanism can be used without prior SDP queries.

When using the SOCKADDR_BTH structure with the connect function, the following requirements apply:

• The btAddr member must be a valid remote radio address.
• For the serviceClassId member, if the port member is zero, the system attempts to use serviceClassId to resolve the remote port corresponding to the service. The service class is a normalized 128-bit GUID, defined by the Bluetooth specification. Common GUIDs are defined by the Bluetooth Assigned Numbers document. Alternatively, a unique GUID may be used for a domain-specific application.
• The port member must be a valid remote port, or zero if the serviceClassId member is specified.

The following table lists the result codes for Bluetooth and the connect function.

Error/error#	Description
WSAEISCONN10056	The connect function called for already connected socket.
WSAEACCES10013	Connecting application requested authentication, but authentication failed.
WSAENOBUFS10055	Unrecoverable out-of-memory error.
WSAEADDRINUSE10048	The port/channel number requested is in use.
WSAETIMEDOUT10060	The I/O timed out at the Bluetooth radio level (PAGE_TIMEOUT).
WSAEDISCON10101	The RFCOMM channel disconnected by remote peer.
WSAECONNRESET10054	The RFCOMM multiplexor (session) disconnected by remote peer.
WSAECONNABORTED10053	Socket shut down by application.
WSAENETUNREACH10051	Error other than time-out at L2CAP or Bluetooth radio level.
WSAEHOSTDOWN10064	The RFCOMM received DM response.
WSAENETDOWN10050	Unexpected network error.
WSAESHUTDOWN10058	The L2CAP channel disconnected by remote peer.
WSAEADDRNOTAVAIL10049	Bluetooth port/channel or device address not valid.
WSAEINVAL10022	Plug and Play, driver-stack event, or other error caused failure.

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SOCKADDR_BTH

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The bluetooth specification allows up to seven devices to connect, but it’s not straightforward, as it is dependent on the type of device and the service profile it provides. For example, you can have a bluetooth keyboard, mouse, and headset connected at the same time, and an A2DP (Advanced Audio Distribution Profile) device to stream music, but you can’t have two devices that performing the same service profile connected at the same time. check the link below for more info.

How to Sync Your Xbox Controller to Multiple Devices at, To get back to your Xbox, double-tap the sync button. To use a secondary device, press and hold the sync button for around two seconds. The Xbox button will blink once or twice before turning solid to indicate that you are paired. Be aware that if you hold the sync button for too long, the controller will …

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How many devices we can pair via Bluetooth of BLE to Android?

A search of the Android Bluetooth Firmware source shows the following:

Max concurrent active synchronous connections ( BTA_GATTC_CONN_MAX ):

Max concurrent active notifications ( BTA_GATTC_NOTIF_REG_MAX ):

As a comparison my experience with iOS is that 8 devices can be connected at at time.

I tried connecting more than 7 devices the other day on Android 7.1 and Bluetooth stopped responding. Starting and stopping didn’t help; the only thing that fixed it was restarting the device.

After working with several apps that connect to 4+ devices I can say from experience that these numbers are theoretical. Depending on each individual device and its hardware you’ll have an easier or harder time connecting to and maintaining a connection to the maximum number of BLE devices.

A master Bluetooth device can communicate with a maximum of seven devices in a piconet (an ad-hoc computer network using Bluetooth technology), though not all devices reach this maximum.

You need know Master/Slave in Bluetooth first.

I think the good answer depend on your aim.

You’re right when you know «can communicate with how many devices» depend on Hardware (Bluetooth Chip) . Bluetooth chip on Apple iPhone 4, 5 or Samsung Galaxy S3, S4 . totally different with Basic Bluetooth Chip .

I’m working with Firmware side related to BLE.

His peripheral device has used Basic Bluetooth Chip since it did not has enough memory to store many capacities as many features, likes Bluetooth chip on Apple iPhone 4, 5 or Samsung Galaxy S3, S4 .

Therefore, his peripheral device only paired with one device in one time .

Can someone else confirm this? This would be a limitation imposed via the Android OS as the hardware should be able to handle more.

I’m more confused now. BLE doesn’t have any concept of piconets, only regular Bluetooth does. I’ve connected 7 sensors with one bluetooth dongle via BLE all at once, so I know that BLE is capable of more than 1 device at a time. So, any limitation would be in the OS and you haven’t referenced anything saying that Android is limited to one device. Also, reTs has connected 4 devices with an Android device, so I’m thinking that it’s possible to connect to more than one.

@Tim Tisdall : hello Tim, u already check this case? How many devices u can connect in the same time?

Both of the answers here are wanting so I thought I should add one:

There are connection limitations built in to the different BLE hardware. I think the lowest I’ve encountered is 3 connections at once and the highest was about 12-13 connections. These were limitations due to the design of the hardware and had nothing to do with the OS being used, though. Usually the limitation is due to the fact that the hardware has to keep track of certain data and there’s a limited amount of memory in the hardware.

So, I don’t know specifically for Android, but it doesn’t make much sense for a limitation to be imposed at the OS level. Likely when you try to make a connection, and you’ve reached the limit due to the hardware, you should receive some sort of error/exception preventing the new connection. I think there’s actually a «connection limit» error in Bluetooth, but some hardware gives other exceptions like «out of resources». Again, I’m not sure how that gets reflected on the Android level.

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