I’m working on a project where a module is suppose to stream an audio signal to multiple receivers via Bluetooth. To be able to connect more than 7 units to this device, I thought of using three Bluetooth transmitters. But when I pair my Android phone to this device, I don’t want to have to select between the different Bluetooth units. I just want to be able to select the device and be paired with any of the available Bluetooth transmitter.
Any idea of how this is achieved?

Also, do you think it would be possible to stream an audio signal to multiple receivers via Bluetooth without pairing the Bluetooth units?

  • \$\begingroup\$ At some point, aren't you going to run out of total bandwidth for devices in the same area? electronics.stackexchange.com/questions/21991/… \$\endgroup\$
    – pjc50
    Mar 19, 2013 at 17:17
  • \$\begingroup\$ Yes that's right of course. Fortunatly I only need to connect a maximum of 20 units to this device. So I don't think bandwidth will be an issue. \$\endgroup\$
    – Johnny
    Mar 20, 2013 at 11:25
  • \$\begingroup\$ Do you mean you are sending different audio to each of up to 20 devices, or the same audio to each of up to 20 devices? \$\endgroup\$ Apr 18, 2013 at 23:13
  • \$\begingroup\$ If it's the same audio to all of them, you could use a wireless router, of the same sort as used for internet, and use that to send the sound packets as a multicast service to all connected devices. \$\endgroup\$ Apr 18, 2013 at 23:19

1 Answer 1


You have 2 issues in here:

1) You want to communicate with more than 7 slaves. It's not possible for a master to have more than 7 slaves. However, it is possible for a device to be a slave in one network and be the master of another (called piconet). However, I have not seen any device that uses this (processing power would also be higher).

2) The issue of pairing the arduino automatically to a device, this is a software issue you need to solve in the app. The Android phone will detect 3 bluetooth devices. Since each has a unique identifier, you can have a simple algorithm to select one of them depending on the criterial, without user intervention.

In Bluetooth you must pair. This has to be done to keep both devices synchronized and talking. I think you're slowly going to the proprietary RF side. Perhaps you should think about your application and see whether you can use a non Bluetooth solution that can enable you to scale.

  • \$\begingroup\$ 1) The idea is that I feed three different Bluetooth transmitters with the same audio signal. Then these three different Bluetooth transmitters could be three masters of three different network. \$\endgroup\$
    – Johnny
    Mar 20, 2013 at 11:18

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