Air Kalon moves a file from one device to another using nothing but a display and a camera. The sender plays the file as a rapid stream of animated codes. The receiver points its camera at the screen and reassembles the file. There is no network involved at any point. It works in airplane mode, in a basement, or between two devices that have never met.
Why not just use AirDrop
Because AirDrop needs two Apple devices, both awake, both discoverable, both willing. Because a hotspot needs a password and a plan. Because a cable needs the right cable. Optical transfer needs a screen, which every device has, and a camera, which every phone has. That is the whole dependency list.
The trick is not the codes, it is the maths
A naive version would show each chunk of the file once and hope the camera catches all of them. It won't. Frames get dropped when a hand shakes, a reflection passes, or the receiver's decoder falls behind. Retransmitting means a handshake, and a handshake means a network.
Air Kalon uses a fountain code instead. Every frame the sender draws is a fresh combination of the file's blocks, chosen by a rule both sides know. The receiver doesn't need any particular frame. It needs enough frames, in any order, and then it has the file. Miss one, catch the next. A dropped frame costs a fraction of a second, never correctness.
The receiver can also lock on mid-stream. Walk up to a screen that has been playing for a minute and start receiving immediately.
How fast
On real devices, verified by hashing the result:
- Mac to iPhone: about 30 KB/s, verified end to end.
- A one-megabyte file takes a little over half a minute.
That is not a replacement for a cable when you have one. It is a replacement for nothing at all, which is what most people have most of the time.
What's next
Air Kalon is a standalone app for macOS and iPhone today. The plan is for it to become an integral part of Kalon itself, so a file you want to hand to the person across the table is one tap away from the conversation you were having about it.