Kernel Bob Aug 13, 2025

Today we got our dishwasher fixed under warranty. To diagnose it, the tech stuck a photosensor+magnet onto the front panel over the green status LED and started reading diagnostics. It turns out the status LED is actually a serial port*, and it's continually transmitting status.

I can think of so many gadgets that could and should use this trick...

*It's probably something other than regular serial -- a UART's TX would flicker. I don't know any details.

#HidingInPlainSight

Show threadThe Penguin of Evil
@kbob lots do. It's also been shown for stuff like leaking data between computers over air gaps long time back.
There's even schemes doing this with stuff like street lamps and traffic lights to talk to cars etc
Aug 13, 2025 at 8:25pmMastodon for Android