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

Timex DataLink. I had the Ironman Triathlon branded model of those, used the hell out of it in high school.

The screen flickering trick also only worked on CRTs under Windows 3.1/9x, so if you had a laptop, any other system with a LCD, or were running NT you had to get a special dongle that hooked up to your serial port and would blink a LED that you had to hold in line with the watch's sensor.

For those that don’t feel like watching a video, it was the Times Datalink.

https://en.wikipedia.org/wiki/Timex_Datalink

Supported in MS Schedule+ 7.0 included with Office 95.

Very magical to hold your watch up to the CRT monitor, see the monitor go black and flash a bunch of white lines for a few seconds and then look at your wrist to view the downloaded info.

But it was only letters and numbers so the routine got old fast.

Could be a bit finicky to get a successful transfer as well.

And transfer bandwidth was pretty low.

I used one for a few years. It was a pretty neat thing for its time.

IIRC it didn't work with a CRT using MS operating systems after Windows 2000 due to driver changes or something.

But Timex also a sold little single-LED blinkenbox that plugged into an RS-232 port that would do the trick. That was intended for computers with LCD screens like laptops, but it worked with later operating systems too.

Bloomberg terminal authentication (screen-sync) works this way too.

Kids also got a toy based off of Timex Datalink - I had one!

https://www.youtube.com/watch?v=A8ig2UPjOXQ

... The DSI e-BRAIN is also fully working in timex_datalink_client, which amuses me so: https://github.com/synthead/timex_datalink_client/issues/111

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 :(

Nowadays, a QR code on one phone, and camera on the other can accomplish data transfer.

Can, but don't. It looks like on Android it creates a temporary link to the VCF file that needs to be downloaded from Google.

I was going to ask "Where on Android", an app like Binary Eye can generate a QR code with the actual data, but Google's Quick Share indeed uploaded the data and generated a download URL.

Fucking enshittification...

I remember IR printing, it was nifty! Had some fun with random public printers and my little HP palmtop…