I don't know if it's the same technology, but I had a microcontroller toy as a little kid where you'd 1) write the programs on your computer (or in my case, type them in from the tutorial book, without actually comprehending any of it) and then 2) transfer the compiled program to the device itself via (IIRC) this little puck-shaped thing with a blinking red light. It was pretty cool, I wonder if I still have it stashed away anywhere.

Huh, now I remember a 90's or early 00's watch that has data, and the way to upload data onto it was by running a special Windows program that would flicker an area of the screen black and white. You'd point the face of your watch to it and the flickering had data encoded onto it.

Since it's 2026, googling brings me nothing... had to ask Gemini: https://www.youtube.com/watch?v=GCHHzw4s5W4

I mostly remember infrared transfers in the context of beaming contacts between PalmPilots. It was pretty fast for that, and actually, much more reliable than modern AirDrop.

I loved IR contact/note sharing! It was easy, fast, and reliable. It also worked across different types of phones.

There's still nothing comparable :(