Send messages to another device over Bluetooth?

Does anyone know how to send any chat messages over bluetooth? There have been a few apps over the years that allow this, but I cannot find any that are active and work on Linux (mobile or otherwise). I am thinking of FireChat (, Jott (, and Briar ( Briar is the only one that still exists, but it only supports bluetooth messaging on android.

This seems like it would be a relatively simple task? A basic chat app that works over bluetooth on Linux? I’m surprised at how little I am finding.

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There isn’t a widely-available mobile Linux platform yet, so there really hasn’t been impetus to develop one.

If you are close enough to communicate via Bluetooth, can you use VoSW (Voice over Sound Waves)? :slight_smile:

What are the kind of use cases where one would want to do chat messages over Bluetooth? i.e. where just using a chat app over the internet is precluded?

Maybe you want to send/receive a file? (and no internet is available)

Dragging something in from another current topic maybe you could use ad hoc WiFi networking / WiFi Direct to achieve this over WiFi rather than over Bluetooth i.e. better bandwidth and more accessible protocols and APIs. So another question would be: what would Bluetooth give you that WiFi doesn’t? I would think that just about any current or recent smartphone would support both WiFi and Bluetooth.

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Presumably, connectivity when there’s no WiFi network available.

Bluetooth would have to act as a relay mechanism, same way apple uses airtags, I believe, minus the internet connection.

Yes but I’m talking about a WiFi network in ad hoc mode. If two devices both have working WiFi client devices then they can establish an ad hoc WiFi network and communicate over it.

This is as distinct from WiFi in infrastructure mode, where each WiFi client device connects only to a Wireless Access Point (WAP) - and all communication between pairs of clients is relayed through the WAP. These days almost everyone uses infrastructure mode almost all the time (and for most home users the WAP is actually integrated within their router).

So if you were talking about two Librem 5 phones, the WiFi and BT are on the same card. You can’t have one radio networking technology without the other and if one works then the other works (modulo bugs and software configuration). But … there may be better documentation for setting up an ad hoc mode network, assuming that the WiFi card supports it, and once you’ve done that, you can just use completely standard networking, and apps should work normally.

Having said that, I think there are profiles around for networking over BT, so that could be an option to investigate too.


I hadn’t heard of that technology, but yes, I see your point :laughing:

Perhaps the biggest advantage of something like bluetooth over VoSW is the potential for mesh networking, as existed with FireChat. With a dense enough group of devices, packets could propagate through the network for miles (Purism will have to increase the shipping rate of L5s :grimacing: ). This could provide cool alternative networks to the internet.

Bluetooth may work better for managing multiple connections at the same time, i.e. for use in creating a peer-to-peer mesh network. The Wi-Fi cards in phones may not have easy default methods for connecting to several devices at the same time?

Somewhat related, I’ve been trying (and failing) to get my (Librem5) phone to act as a bluetooth low-energy peripheral for my watch ( Watchy , my intent is to have the watch vibrate when a notificaton pops on the phone, probably showing notification text too.)

Anyway, I followed this guide but got stuck here:

[bluetooth]# advertise on
LEAdvertisingManager not found
Failed to register advertising object

I don’t know if it means a software bug or missing hardware support…

Ah, OK, that adds another requirement. VoSW can handle that but the error rate is at times unacceptable. :wink: (Chinese whispers)

Fair question as to whether the WiFi card in the Librem 5 supports ad hoc mode with multiple simultaneous pairwise connections. Given that the WiFi card is a blackbox, it may be difficult to find out whether any of these more exotic modes exists and even if they exist, they have to be sufficiently bug free.

But then for Bluetooth to be better, you would have to demonstrate that Bluetooth even works for this application on the Librem 5 (and it’s on the same card).

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Briar has a “linux desktop” version which is supposed to have a responsive GUI, but: 1) it doesn’t have a working arm version and 2) it’s currently missing many features of the Android version, including Bluetooth support. But it’s worth watching and rooting for, in my opinion.