AI Unfolded | Artificial Intelligence on Instagram: "Researchers and hobbyists have shown that a Raspberry Pi and a simple optical sensor can detect motion with a narrow beam of light. When the beam is interrupted, the system can trigger a preset response, such as locking a screen or pausing visible activity. It is a small example of how low-cost hardware can support privacy and security in shared spaces without altering the computer itself. The value comes from early detection, not from hiding