The agency said hackers are using public USB ports to infect and track your electronic devices.

Federal officials are again warning travelers to avoid using public USB charging stations, as the docks can be altered to introduce malware or tracking software onto cellphones.

However, LA officials say criminals can load malware onto public charging stations, so users should avoid using the USB port, and stick to using the AC charging port instead.

Using light isn’t a particularly new way of programming. We’ve seen it used almost a decade back by WayneAndLayne for their Blinky PoV projects, and later by the Electric Imp’s BlinkUp app.