The LED R/C Helicopter’s spinning blades have LEDs on them, which can be programmed to display dot-matrix text or icons which emerge while the blades spin, thanks to a persistence of vision illusion.

Simply enter the text you want to display using the companion app (which appears to be Windows only), choose the animation pattern, and download the data to your helicopter. The text is designed to be legible when viewed from the ground looking up at the helicopter.

Now where is the link to a disaster situation? It would be cool to see this same technology applied to multi-blade drones or even emergency helicopters or air ambulance helicopters. The displayed Text or icons could be used for advising people on the ground to prevent them from damage.