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A decentralized peer-to-peer messaging application that operates over Bluetooth

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Re: A decentralized peer-to-peer messaging application that operates over Bluetooth

#271

Post by londons_explore »

squarefoot wrote: post #238
modeless wrote: post #217

It's criminal that cell phones are bristling with incredibly advanced radio technology and yet they are by law not allowed to communicate directly with each other over a distance of more than a couple hundred meters without assistance from a licensed and centrally controlled base station. Meanwhile a $10 walkie talkie using primitive stone-age radio technology can go many miles with zero infrastructure, but by law is…

A small USB pluggable module that supports LoRa plus an app using Codec2 or similar low rate codec for voice encoding could fill the gap, although having it bundled with the phone would make it a lot less cumbersome to use. For non phone portable solutions, the LilyGo T-Deck Plus/Pro come to mind, but they're not phones so that would imply a 2nd device to carry around.

Yet compared to the 5G radio that can do gigabit speed and 20+ kilometers of range....

Re: A decentralized peer-to-peer messaging application that operates over Bluetooth

#272

Post by lm28469 »

elAhmo wrote: post #188
contracertainty wrote: post #175

Earlier quoted context omitted.

Unfortunately iPhones aren't ubiquitous outside their home market. It would have to be on Android to be really useful in the places this would be really useful , i.e. places where regimes turn off the internet when things go badly for them (current situation in the US notwithstanding). That's not to say iPhones shouldn't have it, I'm all for that.

Home market for iPhones is the whole world.

I mean yeah technically you can buy them pretty much everywhere, but outside of the US there are very few countries where they're above 50% of market share. They're below 30% in the vast majority of countries actually

Re: A decentralized peer-to-peer messaging application that operates over Bluetooth

#273

Post by lxgr »

kanbankaren wrote: post #270
lxgr wrote: post #265

Earlier quoted context omitted.

No, attenuation in vacuum is exactly the same, and the difference between humid air, dry air, and vacuum doesn't really matter at frequencies below a few GHz. > For example, attenuation at 1 km for 144 MHz (ham VHF band) is about -76 dB while for 2.4 GHz, it is about -100 dB. This is a common misunderstanding of the free-space path loss formula, which is expressed in terms of the idealized isotropic radiator, the len…

> With the same antenna size, the path loss is exactly the same. What do you mean? The size of the dipole or monopole antenna is dependent on the wavelength, so obviously the 2.4 GHz is just a few centimeters and not the same size as a VHF antenna. > After all, where else should the radiated energy go? Well, most of RF energy is wasted. There are software that can plot the radiation pattern, but even without knowing…

> The size of the dipole or monopole antenna is dependent on the wavelength, so obviously the 2.4 GHz is just a few centimeters and not the same size as a VHF antenna.

Sure, if you want to stay omnidirectional, but you don't have to. You can use one of several antennas based on feedback, beamforming etc.

Re: A decentralized peer-to-peer messaging application that operates over Bluetooth

#275

Post by catlifeonmars »

modeless wrote: post #217

It's criminal that cell phones are bristling with incredibly advanced radio technology and yet they are by law not allowed to communicate directly with each other over a distance of more than a couple hundred meters without assistance from a licensed and centrally controlled base station. Meanwhile a $10 walkie talkie using primitive stone-age radio technology can go many miles with zero infrastructure, but by law is…

Check your sources. The law you claim exists… which one is it?

Re: A decentralized peer-to-peer messaging application that operates over Bluetooth

#276

Post by ssl-3 »

rm30 wrote: post #244
nicois wrote: post #26

One missing feature: deferred message propagation. As far as I understand, while messages will be rebroadcast until a TTL is exhausted, there is no mechanism to retain in-transit messages and retransmit them to future peers. While this adds overheads, it's table stakes for real-life usage. You should be able to write a message and not rely on the recipient being available when you press send. You should also be able…

I’ve read all the posts and, as the 'old man of the village', I would suggest taking a look at FidoNet. It was running 40 years ago, for more than a decade, before the internet was available to the average person. Store-and-forward, hierarchical organization, scheduled transmissions, working over dial-up and radio links, everything is there. There is nothing new to invent, and it was far more reliable than the 10m re…

FidoNet has a lot of it solved, for sure. But doesn't it rely upon pre-configured paths between nodes in order to handle message routing?

If so, then: Wouldn't it fall down completely when operating in the ever-shifting and inherently disorganized environment that a sea of pocket supercomputers represents?

Re: A decentralized peer-to-peer messaging application that operates over Bluetooth

#279

Post by catlifeonmars »

rm30 wrote: post #260
digiown wrote: post #224

Earlier quoted context omitted.

Will the walkie talkies work if there are hundreds in a small area all transmitting data with each other? Besides, there's just not that much bandwidth there.

The smartphone is just an advanced walkie-talkie, currently limited only by the mobile operator, the law, the radio chipset, and the OS. In a true emergency, who can stop you from modifying that architecture? Once you treat the device as an independent radio node (using its DSP power to run custom modems) you can establish a mesh network with a range of several kilometers. We have a '4x4 car in our pockets; we’ve jus…

Not disagreeing with you, but you’re papering over a lot of complexity.

Note that cellular radios are highly specialized and the filtering circuits are tuned to specific bands. It’s not exactly like having a software defined radio in your pocket.

Next, at the modem level, you’ll need to implement and then sideload custom firmware. Finally, you’ll need to expose the right APDUs to the kernel to manage the whole thing.

TBH it sounds like a fun side project, but my point is you need to repurpose a lot of different parts of the stack to accomplish what you want.

Re: A decentralized peer-to-peer messaging application that operates over Bluetooth

#280

Post by alecco »

NoiseBert69 wrote: post #208
alecco wrote: post #206

Meshtastic + budget kit ($10-$35) is way better. BlueTooth alone is kind of useless. It's max ~100 meters/yards vs 2-20 km (12 miles). And the community is great.

Meshtastic has a reliability problem. We often cannot get beyond one hop - and our network isn't too loose nor too dense (60 stations). Cross test with Meshcore doesn't show any issues. Chats over 5 hops have almost a 100% success rate. Long time I avoided MC because of its closed source client - but a Opensource Flutter app for Apple/iPhone is slowly getting usable and stable. ( https://github.com/zjs81/meshcore-ope…

Sounds good. But there are ~10x fewer nodes in my area :(
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