SOMEONE BUILT A WAY TO SEND FILES BETWEEN TWO PHONES WITH NO WIFI, NO BLUETOOTH AND NO NETWORK AT ALL
it works with just a screen flashing qr codes at a camera
one device plays an endless stream of animated qr codes, the other one points its camera at the screen and rebuilds the file out of the light
no pairing, no app, no shared network, nothing but the camera
> its pulling about 129 kb/s, a full 2mb image transfers in seconds
> theres no back channel, the receiver can never ask for a missed frame, so it uses fountain codes, every frame is a scrambled mix of the file rather than one piece of it
> that means the receiver just collects any frames it can catch in any order, and once it has enough it can reconstruct the whole file
> dropping frames costs you a little time but never breaks the transfer
> you can point the camera at a stream thats already running and it just locks on mid flight
he was building a cached mp3 player because he was sick of ads and bad streaming quality. he wanted a way to send tracks phone to phone without both phones being on the same network, and realized flashing qr codes could carry the data
he built the whole working prototype in one night with claude code
its open source and already at 375 stars
