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Decimen Optical Transfer: fountain-coded QR file transfer

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Re: Decimen Optical Transfer: fountain-coded QR file transfer

#11

Post by account42 »

krautsauer wrote: post #8
atoav wrote: post #6

Earlier quoted context omitted.

I have seen digital audio gear that solved firmware transfer like that. You basically go to a website on your phone and it flickers the screen and you hold it in front of a photosensitive bit of the device that needs to be updated for 20 seconds and done. If your firmware is small enough to fit that model, it isn't a bad variant. Beats downloading a file, transferring it to a USB drive, sticking that in,...

That'd be a few 100 bytes at best… what firmware fits into that?

100 bytes in 20 seconds would only be 40 bps. Surely you can do better than that even using only one bit symbols (off/on).

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#12

Post by krautsauer »

elric wrote: post #2

Neat, finally an easy way of transferring files between devices that doesn't rely on online services -- no clue why we didn't solve that ages ago. Adding encryption shouldn't be hard, as long as you can communicate the keys out of band. Could probably achieve the same result using audio instead of video, but maybe that would be too annoying?

Have a look at minimodem. In short: yes, but it's slow and annoying.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#13

Post by utopiah »

elric wrote: post #2

Neat, finally an easy way of transferring files between devices that doesn't rely on online services -- no clue why we didn't solve that ages ago. Adding encryption shouldn't be hard, as long as you can communicate the keys out of band. Could probably achieve the same result using audio instead of video, but maybe that would be too annoying?

Indeed encryption should not be hard yet which situation do you have in mind where simply pulling away the emitting phone would not be enough? AFAIK the normal scenario is two persons in the same physical space so I am not sure what encryption would add.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#14

Post by felooboolooomba »

Is there a way to negotiate ongoing FPS? I was sending at 60 but only receiving at 40. When I changed TX to 30 the speed went though the roof! I better call a builder.

Otherwise ridiculously cool project. May author's pillow always be cool on both sides.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#16

Post by inigyou »

_joel wrote: post #10
atoav wrote: post #6

Earlier quoted context omitted.

I have seen digital audio gear that solved firmware transfer like that. You basically go to a website on your phone and it flickers the screen and you hold it in front of a photosensitive bit of the device that needs to be updated for 20 seconds and done. If your firmware is small enough to fit that model, it isn't a bad variant. Beats downloading a file, transferring it to a USB drive, sticking that in,...

If only they had a clean digital way of getting data into the system.

Listen, you do not want your firmware to be updated by playing a FLAC file.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#17

Post by inigyou »

kooi wrote: post #3
elric wrote: post #2

Neat, finally an easy way of transferring files between devices that doesn't rely on online services -- no clue why we didn't solve that ages ago. Adding encryption shouldn't be hard, as long as you can communicate the keys out of band. Could probably achieve the same result using audio instead of video, but maybe that would be too annoying?

As someone who has implemented acoustic modems (underwater comms)... yes, yes very annoying. It's like a demonic dolphin. Bringing it into the ultra sonic band would help.

Fun fact about underwater acoustic data transfer and sonar: the extreme volumes used (130dB+) kill fish in the area.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#18

Post by XorNot »

inigyou wrote: post #17
kooi wrote: post #3

Earlier quoted context omitted.

As someone who has implemented acoustic modems (underwater comms)... yes, yes very annoying. It's like a demonic dolphin. Bringing it into the ultra sonic band would help.

Fun fact about underwater acoustic data transfer and sonar: the extreme volumes used (130dB+) kill fish in the area.

Fish also substantially limit the range, so no one comes out happy.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#19

Post by _joel »

inigyou wrote: post #16
_joel wrote: post #10

Earlier quoted context omitted.

If only they had a clean digital way of getting data into the system.

Listen, you do not want your firmware to be updated by playing a FLAC file.

FLAC? That shows some degree of advanced technology that I would assume the original device in question does not have.

Re: Decimen Optical Transfer: fountain-coded QR file transfer

#20

Post by myself248 »

ErroneousBosh wrote: post #7
elric wrote: post #2

Neat, finally an easy way of transferring files between devices that doesn't rely on online services -- no clue why we didn't solve that ages ago. Adding encryption shouldn't be hard, as long as you can communicate the keys out of band. Could probably achieve the same result using audio instead of video, but maybe that would be too annoying?

You can do PSK31 across a room with just audio, but it is a kind of annoying noise after a while. It's interesting that you learn to recognise patterns in the burbling tones after a while. "CQ CQ CQ" is very distinctive and after a while you can hear your own callsign in it. I guess it's not that different to very fast Morse.

Or SSTV! I recall a demo years ago where someone had SSTV running between a speaker at the focus of a small dish, across to the room to another small dish with a microphone...
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