It is a pretty common first project to use an Arduino (or similar) to blink an LED. Which, of course, brings taunts of: you could have used a 555! You can, of course, also use any sort of oscillator, ...

Researchers say sensitive data can be extracted from air-gapped networks via a wireless router’s blinking LEDs. Researchers have uncovered a new data extraction hole inside air-gapped networks that ...

Air-gapped computers aren't physically connected to any network and so should be protected from remote hackers. However, Stuxnet showed air-gaps can be breached. Besides that, an insider could always ...