I'm trying to connect several bluetooth devices with Raspberry PI to use them as speakers.
I'm using RetroPie as a distribution, because of the tests I've done it's the only one that matches and allows continuous synchronization with several bluetooth devices at the same time.
However, the system only detects the first device that connects as a sound card, the rest keep the bluetooth synchronization active, but it does not interpret them as audio cards even though it is indicated by blueman-manager.
Is there anything I can do to keep all devices synchronized and supported as audio cards?
Palm,
even so this a old post, it is not yet closed.
As I just got the same issue, here my answer.
What you try to do is to connect mutliple audio sreaming services (Speakers) to 1 audio bluetooth source, that is not possible like this. Therefore your PC only connects to the first box.
You could try multiple bluetooth dongles, but then you run into the timing issue with audio stream syncronization between the boxes.
The only solution is to use Bluetooth 4.1 upwards master-slave services.
Therefore the Speakers need to be connected to each other and seen as 1 device from the PC. In that mode the stream is skewed to ensure syncronous playing.
Many new Bluetooth speakers support this mode.
Hope that helped.
Related
I am using BLE v4.1 for my application where I am able to transfer 200 packets of length 20 bytes each from peripheral to central side.
I want to transfer data via BLE and play some music while the data is being transferred. The music file is available locally and will be played on earphones(can be wired or wireless BlueTooth earphones)
I am facing an issue of packet drops around 15-20% when I am playing audio through wireless earphones while data is being transferred via BLE and audio is played on phone Bluetooth earphones(tried on Android and iOS, both) simultaneously.
With wired earphones connected; there is no issue, I can transfer data via BLE and play audio smoothly without any issue but things are different with wireless Bluetooth earphones case. I tried it with different Android phones(Android 11, different manufacturers) and different BlueTooth earphones, the issue still exists.
What could be a cause for the same and how can I debug it?
Bluetooth and Bluetooth Low Energy has only one radio that can only do one thing at a time. The connection events are scheduled and cannot overlap. This means the throughput is shared among all connected devices. You will get a higher throughput per device with only one connection than with two connections.
You will have to experiment with connection interval and connection event length to find parameters that seems to work, and test with multiple Bluetooth controllers (phones), since all have different scheduling algorithms.
I never used a raspberry pi before and I have a project part of which includes receiving data from a BLE blood pressure device over Bluetooth to a raspberry pi 3. I can pair the device to my raspberry but I have no idea what to do next. I need to be able to receive the measurements in my raspberry please help and thank you in advance.
PS: the device I'm trying to use is very similar to this one:
https://ibb.co/71365k5
Thanks for your answers, I have tried "Gatt" and "Gatttool" but the problem is after pairing the device is meant to send the measurement to its application on an android phone, without it I cannot read the blood measurement characteristic or it just does not exist.
Linux uses BlueZ as a default bluetooth stack. It exposes DBus APIs for implementing software using Bluetooth.
If you don't want to use this API directly, which can sometimes feel a bit low level you have many libraries that wrap it, such as https://github.com/getsenic/gatt-python that also comes with examples.
All other solutions requires replacing the Bluetooth stack on Linux and hence your other existing Bluetooth pairings to the system will stop working.
I need some help because I don´t know how to approach this challenge.
I want to build a device, that's receiving a Bluetooth audio signal and is forwarding it to a Bluetooth speaker. It´s also running some algorithms with the audio data and also simultaneously sending results via UDP to a different device.
I already thought about using two or three ESP32s, using one with an extra Bluetooth module, or searching for a whole different MCU with Bluetooth 5.0 or higher and Wifi 5GHz. But I don´t know approach the best is, or maybe a completely different one.
Some context, why we want to do it:
We want to create a real-time light show, based on the current playing song. It is already working for PC, but also want to make it accessible for phone users. Sadly there is no way to capture the internal audio on iPhone or Android phones. Our Idea to make the music sync with the phone possible is that you are connected with the phone via Bluetooth to our "sync box" which is then connected to the speaker via Bluetooth or AUX. The "sync box" is running our algorithms for creating the light shows and then sending the data to the microcontrollers from the light strips.
So maybe you have an idea how we can sync the lights to the music completely differently or how I can approach the challenge with Bluetooth.
Any help is highly appreciated.
Thanks a lot.
I have a bluetooth headset. When connecting it to Windows 10, it installs two profiles in Playback devices list:
Hands-Free. (HSP profile)
Stereo. (A2DP profile)
The Second one (Stereo) is set to be the "Default Device" and the "Default Communication Device" on the system.
When I start any program that uses the mic (recorder, chat, VoIP Calls, gaming, etc.) The sound suddenly stops working And I can only use the mic until I stop the recorder or the call.
To enable the sound again I need to make the Hands-Free (HSP) profile handle both input and output (sound and mic). Unfortunately, HSP gives really poor sound quality.
I want to know If there is a way, using code, I can change Bluetooth behavior so the two profiles work simultaneously. One handles the sound and one handles the mic so I can have high quality sound and use the mic at the same time.
You will probably never find a solution. I had the same problem (I was trying to create a walkie talkie with 2 headsets connected to the same smartphone).
On Windows (but also on Android) you can't access directly to a BT-microphone or BT-speaker because it is automatically detected as BT headset and the OS take the control of the device.
Your app can then access the OS-device and not directly the hardware device. The only OS able to do that was Symbian I think which had the most BT-protocols. On Windows you will probably never be able to do that and on Android you have to write your own A2DP-protocol if you want to access the device directly without OS interference.
So sad...
Luckily, under windows you can define different devices for communications and sound.
So, you have two choices:
Choosing Hands-free for both mic/speaker only for communication (which will switch back to A2DP after the call/teams).
Choosing another mic for communication which allow you to still use the speaker profile even in communication.
That is a bluetooth restriction : A2DP (high quality audio) cannot be use simultaneously with HFP (hands-free profile)
Is it possible to send the same audio signal to two different Bluetooth speakers at once from a single source?
I remember reading somewhere that it's possible to send audio to two different sinks using PulseAudio, but I'm not sure if that applies to Bluetooth speakers or if Bluetooth has a built in limitation on something like this.
Bluetooth works as a source and sink profile. Normally phones are source devices and bluetooth headsets/speakers are sink device. If source has a capability of connecting 2 sink profiles at a time, audio can be send to 2 different devices,not sure if the device(Audio Source) which you have is capable to connect AVDTP(Music profile) profile with 2 devices at a time