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770 points ananddtyagi | 16 comments | | HN request time: 0.837s | source | bottom
1. syntaxing ◴[] No.44485489[source]
Whoa this is really neat. I’ve been trying to get into Meshtastic but it’s hard to convince others when you need special hardware. Would be super neat if Apple did something similar. Shouldn’t be too hard since the AirTags use the same idea?

Would also be neat if there was a way to build a LoRA proxy to extend the range. I might give this a try with my meshtastic devices.

replies(7): >>44485571 #>>44485745 #>>44486004 #>>44487096 #>>44487667 #>>44488123 #>>44498072 #
2. eternityforest ◴[] No.44485571[source]
I'm working on a project that uses the same kind of idea as the Bluetooth tracking tags.

It's an Arduino library for mesh networking, that works over BLE and UDP, but it can also link to MQTT.

An MQTT node routes the packets it sees to the appropriate topics, and subscribes to topics for all the channels local nodes want, so you should be able to talk to anyone anywhere via the gateway.

The packet destination addresses are rolling codes, so you can't tell if someone's online just by watching their channel, at least not for more than an hour.

And there's a web app that talks directly to the public MQTT broker, and it can do chat and sensor data.

All payloads are Messagepack to make it easy to add new data types, and all packets are encrypted, authenticated, and timestamped to provide a bit of replay protection.

Everything is purely symmetric crypto, trust is left to a higher layer or something out of band, so you there's no handshakes or connection state management overhead, aside from one announce packet per hour to make the MQTT gateways work.

No LoRa, but the transports are modular and pluggable so you can easily add them. I just only have one LoRa Arduino node here so I haven't bothered writing a driver.

I'm also working on a Python port for easy pip-installable bots and home automation stuff.

https://github.com/EternityForest/LazyMesh#

replies(1): >>44485611 #
3. syntaxing ◴[] No.44485611[source]
Super interesting! Leaving the transport layer as modular is definitely a great choice! I like the idea of MQTT because there’s a lot of methods of serving it. I’ve been in the middle of setting up a meshtastic MQTT mode to try it out.
replies(1): >>44485702 #
4. eternityforest ◴[] No.44485702{3}[source]
I was originally going to do OpenDHT, but that would have required building and paying to host a proxy backed for the web app.

I wonder what other transports you could do, like 38khz IR through a telescope?

replies(1): >>44485958 #
5. myself248 ◴[] No.44485745[source]
It'd be cool if Meshtastic's UDP mode could run over BLE like this, for local bluetooth clouds linked by just a few LoRa nodes.
replies(1): >>44485916 #
6. syntaxing ◴[] No.44485916[source]
Yeah, a BLE first mesh system honestly makes more sense in today's world since it's baked into every phone. In theory, a BLE to LoRA bridge should be doable with the existing meshtastic hardware like Nordic's nRF52840. The biggest caveat is going to be the data rate. Meshtastic is designed for around 200 bps (Long range mode) which vastly pales the ~2Mbps BLE expectation.
7. syntaxing ◴[] No.44485958{4}[source]
Any line of sight stuff can be tough. Another one is standard 433 radio but difficult since its such a noisy environment.
8. K0balt ◴[] No.44486004[source]
It depends on the antenna efficiency of course, but I was surprised to discover that BLE modes around 128kbps using coded-PHY have a range extending over 1-1/2 km without a directional antenna. At 2.4ghz its line of sight, of course, but still…
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9. kragen ◴[] No.44486615[source]
That's extremely surprising to me too. I would have expected BLE to reach a few meters, not kilometers. How can I learn more?
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10. imoverclocked ◴[] No.44487096[source]
Once you have brought LoRa into the mix, you might as well just ask for p2p cell connectivity. Our phones could totally talk to each other over reasonable distances with no extra infrastructure.
11. estsauver ◴[] No.44487667[source]
FWIW, I've found a T-1000e to be a pretty good way to get people into meshtastic. It's not perfect because it has a weird dongle to charge, but it's pretty cool and I think you can convince people it's a worthwhile thing for emergency recovery.
replies(1): >>44488606 #
12. fragmede ◴[] No.44488123[source]
the special hardware's cheap enough that if they can't be bothered, then they're not serious about it.
13. RenThraysk ◴[] No.44488606[source]
Heltec MeshPocket is another. A powerbank and LoRa device.
14. Aurornis ◴[] No.44489786{3}[source]
Search for “BLE coded PHY”.

The S8 coded mode with 125kbps rate is the long distance one. Support for it in phones is not widespread, sadly.

replies(1): >>44491742 #
15. kragen ◴[] No.44491742{4}[source]
Thanks! I didn't realize that was the key phrase.
16. jamaicahest ◴[] No.44498072[source]
I think the reason AirTag works is because Apple turns it on-by-default on i-devices and people can't be bothered to go turn it off. For a chat to work on the same scale it would literally need Apple or Google to ship it as enabled-by-default on all phones.