Bluetooth connect many devices

how many bluetooth pairing can be made?

I have an android phone and I want it to communicate with 10 bluetooth modules, not simultaneously. I know that a master device can have 7 slaves for bluetooth connection. does it mean «pairing»? The question is can I have my phone paired with 10 bluetooth devices? Then send them data seperately?

2 Answers 2

There is no set limit on the number of pairings possible for a device, except for any limitations made by the platform or bluetooth software stack (eg. limited storage).

Bluetooth pairing and connecting are two separate operations.

When two Bluetooth devices pair, they will exchange Bluetooth addresses and encryption keys. If pairing is successful, it allows the devices to connect to each other at a later time.

When two bluetooth devices connect, the profiles are established (a2dp if a speaker, hfp if headset, etc), and they can communicate.

Sometimes there is confusion between pairing and connecting since most smartphones automatically connect after detecting a successful pairing.

Pairing is just done once, typically when you buy a Bluetooth product. Connection is done whenever you use the product.

The question is can I have my phone paired with 10 bluetooth devices? Then send them data seperately?

As mentioned in the other answer, the maximum number of paired devices is platform dependent, it varies from product to product, but there is no set limit. The maximum number of connected devices (that you could send/receive data concurrently to) is 7 according to the Bluetooth specification.

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How to connect multiple bluetooth devices to a single device

Most people have Wi-Fi routers in their homes to connect them to the internet. But have you ever heard of a Bluetooth router? With the release of new technology such as a Bluetooth Hub, you may be wondering what you might need it for.

For a start there are more devices and gadgets manufactured that are now wireless. These devices are considered more convenient as there are no annoying wires to plug in, get tangled or create an awful mess around electronics.

But with these wireless devices, you need something to connect them all to a source so you can use them effectively. So this is where your Bluetooth Hub comes in.

What is a Bluetooth Hub?

Bluetooth is a technology that you may use on a daily basis. Yet it has two significant drawbacks. The first drawback is that Bluetooth devices can only be paired on a one-to-one basis. Secondly, the range of Bluetooth is short which means many devices cut out when you move more than 30ft away from the connection source.

One of the leading Bluetooth Hub brands on the market is the Cassia Bluetooth Hub and it can solve both of these problems. The Hub is a white cylindrical device that’s about 8″ in length and 5″ in diameter.

At the back of the Hub is a USB 2.0 port, an Ethernet port, power adapter and LED indicator. The Hub can be hooked up straight through the Ethernet or through the Wi-Fi router easily. But depending on the brand the device could operate differently. So how do Bluetooth Hubs work?

How Does a Bluetooth Transmitter and Receiver Work?

There are many types of Bluetooth devices you can connect to that perform other tasks. All it needs is a Bluetooth transmitter to make pairing possible. They work by decoding information such as songs into a transferable format before transmitting that information through radio waves to the receiver.

The transmitter produces audio frequencies which are then detected by the receiver. Together the transmitter and the receiver create a pathway through which data can be transferred.

In the modern world, Bluetooth is an important feature for most applications including mobile phones, TVs, laptops and speakers. If you’re looking for any Bluetooth device it should support version 4.0 as it’s the latest Bluetooth transmitter. But version 2.1 is also more than adequate for everyday applications. With version 2.1 you can pair devices such as Bluetooth headphones or speakers.

You should also consider the range of the Bluetooth transmitter. For instance, if you’re using Bluetooth speakers and your transmitter is inside but you want to hear your music outside you’ll need a device with a longer range. This will prevent the radio signal being interrupted.

As mentioned before standard devices allow for a range of up to 30ft but with Bluetooth Hubs you’re able to connect devices from as far as 1000ft away.

Connect Multiple Devices

Depending on the brand you can pair and stay connected to the Hub with up to 22 devices. You can organize these devices into groups so you can access them quickly and easily. Here’s how to connect multiple Bluetooth devices at the same time.

Some brands such as the Cassia allow you to set up your Bluetooth router through your SmartPhone. If your device has the same feature it should be compatible with Android and Apple applications.

Your SmartPhone application allows you to manage your paired Bluetooth devices easily even when you’re not at home or near the Hub. The 22 devices can all be different from speakers to printers and even TV sets.

Simply download the compatible app on your SmartPhone so you can pair it to your Hub. Switch the Hub on either by using a specific button and use the Bluetooth on your phone to connect to the Hub. Turn on all your Bluetooth receivers so the Hub can connect to them.

On your mobile application that’s compatible with your Hub, it will show all your Bluetooth devices that are turned on. Here you can control the devices straight from your mobile phone. Easily turn on TVs, lights, kettles and radios with a click of a button through Bluetooth transmitters & receivers.

What if Your Device Doesn’t Have Bluetooth?

Not all electronic devices have Bluetooth receivers. In order to convert your device, you’ll have to purchase a portable Bluetooth receiver that you can connect to your device via a cord.

You can turn an ordinary device such as a pair of headphones into a Bluetooth receiver by simply plugging in a portable receiver. People do this with myriads of applications so they can easily control the devices using their Bluetooth Hub.

Can you Connect Multiple Speakers?

If you have an event and you have no idea how to use a soundboard or how to connect all your speakers at the same time, a hub can help you with the task. This is of course if the speakers have Bluetooth receivers.

Simply turn all your Bluetooth speakers on so they can be discovered by the Bluetooth router. Here you can play music with SoundCloud, YouTube, Deezer or even through your phone’s music media via your SmartPhone application.

You can pair four or more speakers at the same time and place them all over the house to transmit sound.

Troubleshooting when Connecting Bluetooth Devices

If you’re experiencing interference or signal dropouts, scan the environment you’re using your Bluetooth device in. The quality of the Bluetooth connection can be negatively affected by concrete walls, microwaves and other wireless devices such as portable radios or cordless telephones.

Final Thoughts

Do you have an application with a Bluetooth router? Turn your Bluetooth on and experiment with how many devices you can connect to simultaneously. You’d be surprised at how many applications out there have Bluetooth technology and the number of devices you can pair to.

Modern technology definitely makes life interesting, find more at Outeraudio!

Final thought. Who has not heard about classic Solitaire card games?

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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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