[sardine5]

A bit different, as it's mainly for voice - but I made an app 'Murmur : Bluetooth Group Calls' - that lets you hold group voice calls and message via a mesh of Bluetooth LE connections. It's available on Android and iOS. https://apps.apple.com/gb/app/murmur-bluetooth-group-calls/i...

Doesn't really get any downloads, so not sure there's much demand for this - but I use it with some shokz bone conducting headphones for talking to my wife when we're cycling (also for wrangling our two small girls)

[driverdan]

I'd guess you're not getting downloads because you're not marketing it to people who want it. You mention a few use cases at the end of the short description and that's it.

For example, this completes with motorcycle communicators such as Sena. That dedicated hardware can be over $400. If your app is as easy to use as a Sena device and you market it to bikers looking for a cheaper alternative you'll get users.

[subscribed]

LOL, no. You can't even hear a ok quality music further than 20 metres away. Class 2 devices (smartphones) have maximum theoretical range of 30 metres with 2.4mW (4dBm).

Sena or Cardo work in 2.4 Ghz (ISM) range as well, but as a class 1 devices, which with 100mW (20 dBm), they can allow for maximum range in excess of 1 mile.

I'd use Walkie - talkies (PMR 446 MHz, about half of a mile of the range in the town) before resorting to the smartphone bluetooth. Likely only feasible on the parking.

Smartphone bluetooth is fine for two bicycles but it does NOT compete with a purpose-built hardware, especially not with the top makers like Cardo or Sena, LOL.

[LWIRVoltage]

Okay, this is neat! A true mesh networking bluetooth app- The other one that's notable, Briar is super impressive - but i think it doesn't actually have proper mesh capability due to difficulties with how devices handle things

(See: https://old.reddit.com/r/Briar/comments/gxiffy/what_exactly_...

https://news.ycombinator.com/item?id=43363031 }

Anyway, -Question: I take it Murmur is end to end encrypted fully? Also, just curious if this is open source?

This could become SUPER useful- having a actual mesh networking Bluetooth app , if it's open source/E2EE!

[sardine5]

It's AES128 encrypted with a key derived from the group password.

[subscribed]

I'll try this app because Briar never worked between any of my devices (all Androids)

[Karrot_Kream]

How's the range on BLE? I was looking at this app for exactly the use case you mentioned but was curious if it worked with varying distances on bike rides

[sardine5]

It's somewhat device dependant - but between her Pixel 6 and my Pixel 7 - if we've got line of sight and the handset's not being held to our body (so in a handlebar mount or saddle bag) - 50-75m? I've been victim to the recent Microsoft layoffs, so have a bit of time to work on it at the moment - looking at adding longer range CodedPhy support this week (though that would only be available on Android)

It works best if there's 3 phones though - as it can route via the other if a link drops.

[cpeth]

Any chance it could use seamless transport switching? It would be so awesome if it could switch to cellular(if available) or wifi-direct as needed on the fly. I have been thinking about creating such an app but lacked the time.

If it's open source, I would love to help.

I will give your app a try.

[sardine5]

I actually have this kind of working on a branch - really don't fancy hosting any infrastructure myself though - so I was intending it to be a Windows service or docker container you have to setup and pair with. Once you've done that - the endpoint is included in any group you create, and treated as an extra node in the graph. If available and lower latency than other routes, it'll be used.

Was trying to keep things simple though - the separate server seemed a step too far for most people I talked to about it.

[sardine5]

I'd stayed away from WiFi Direct because Android and iOS don't play nicely with it - but looks like the EU has forced Apple to support WiFi Aware in iOS 26. It still looks like it would require A LOT of manual pairing through the system UI if you join a group with new people though. I really wanted to keep the single password (or qr code scan/NFC tap) to join.

[roshin]

Cool technology, but what is the usecase? I can imagine traveling abroad without a sim and using it as described. But is it any better than using the cellular network (when you have access to it)?

[sardine5]

I possibly live more remote than you do - but mobile data isn't really a thing (in the UK at least) you can rely on continuously when you're cycling, or visiting the supermarket and you've lost your partner near the cheese aisle...

[toast0]

I've still got dead zones near me. If I were cycling with someone, and we wanted to chat on headsets, there's at least a few places I might ride where we'd hit dead air. If we're on different networks, then we both need coverage to communicate with cellular.

Might be more reasonable to use higher bandwidth, lower latency codecs over bluetooth as well?

[kaiken1987]

Cardo uses a similar tech for a dynamic mesh network, using Bluetooth I think, in their helmet comms. So if you are out on motorcycles or ATVs you can still talk without needing a cellular network. It makes things a lot more stable and not use any data. In these scenarios you'd struggle to talk face to face wearing helmets without some sort of comm. So if you can remove the need to buy a specialized comm device to do it, sounds great.

[dfc]

I would love to use it to talk to my girlfriend when we go bike riding. I was shocked by the price tag for all the motorcycle helmet comms systems.

[nullify88]

I commonly Signal call my partner when we are at opposite ends of the house. I can see something like this being useful to prevent using some remote Internet server to facilitate a very local call.

I wonder if there's a home lab / self hosted solution for this.

[wickedsight]

On festival sites and other crowded events, cellular sometimes gets quite saturated and slow. This might be a good alternative.

Also, I could see it as a useful tool in emergency situations. But a lot of people would need to use it to be actually useful.

[summm]

Unfortunately you have generated a name collision: the server component of the Mumble VoIP is also called "Murmur", for a long time: https://en.m.wikipedia.org/wiki/Mumble_(software)

[numpad0]

Yeah, I think that fully explain apparent disinterest of users. No way nobody is looking for this app, but there is also no way this one shows up on searches over the other one.

[Orbernator]

This is really interesting! Will have a look!

[rjmunro]

This looks really cool. I'd see it being useful as a headset to talk to camera people and others during a live stream. We already have hardware for this, but if we didn't it would be great.

For my use, I'd like to be able to join and monitor multiple groups at once (cameras, presenters, certain others individually), and select which I talk to (including being able to talk to several or all groups at once).

Another feature idea, if you are out of range, it would be good if there was an option to save the message until you come back and replay it.

[sardine5]

Thanks! The protocol it uses does allow broadcasting to a subset of the group - I haven't hooked that up to the UI yet, but it's on the todo list (after CodedPhy and IP fallback).

Re. Messages - if you're not in range, as long as you don't leave the call, it'll send as soon as you reconnect. Messages are not currently persisted to a database though (- unsure if that's a feature or not?). I'd wanted to hold off on that until I was sure I'd covered everything I needed for the schema - they're currently encoded with ITA-2 (which is why some punctuation and emoticons go missing) - but I've made some improvements to the protocol, and intend to move to UTF-8 for broader character/language support.

The current protocol is very much designed to work around all the ways streaming audio really isn't a good fit for Bluetooth LE GATT. It does things which don't really make sense for messages, so I'm intending to separate messages from the live call.

The current focus is trying to make it play a little better with wireless headphones though. I started the app back in the days when phones had 3.5mm headphone jacks. If you've an Android phone and can use LE Audio headphones - they work much better, but wired headphones work best.

[lhoff]

Looks interesting, especially that use case. May I ask which headphone you are using? I have the older openmove from shokzs and voice isn't really understandable while riding a bike.

[sardine5]

We've got Openrun Pros - wind can be a problem, but if you cover the mics with a head band, it actually works pretty well. (To act as a crude wind muff)