OCR from smartphone camera could easily make mistakes that would be difficult to detect and correct. What I would do is look for some kind of encoding that mak

OCR from smartphone camera could easily make mistakes that would be difficult to detect and correct. What I would do is look for some kind of encoding that makes errors extremely unlikely. If I had to dump the entire laptop's drive, I'd rather leave the laptop running for a week once than use a faster method that introduces errors. I don't know much about error correction, so let's take naive approach. 320MB (drive size) in a week is 530 bytes per second. I don't know what's the screen refresh rate (and reaction time) but it's sensible to assume that if we display any image at 4Hz and record it with a smartphone, we won't miss frames or have any other funny artifacts. So it's like 135 bytes per frame, which is 1080 bits. If we divide the 8.4 inch 640x480 screen into squares 16 by 16 pixels, then we have 1000 squares 0.5 by 0.5cm. If each square is either black or white for 0.25 seconds, then camera artifacts shouldn't affect the transferred data too much, and the bandwidth is almost exactly what we need.