A persistence of vision (POV) display is a device that creates an apparently still image using rotating LEDs with great speed. The human eye is not able to distinguish every image individually, so the picture formed appears as a solid image. The POV phenomenon is not a new discovery and a lot of POV display projects have been made. However, this one right here has two different attributes that differentiate it from other POV displays: it is located on a fan placed on a ceiling and it’s silent.
This project uses a fan with 5 propeller blades and every blade has 32 LEDs mounted on it (that means a total of 160). These LEDs are connected to an Atmel microcontroller on an Arduino board. The POV display also uses 74HC595 8-bit serial-in, parallel-out shift registers that convert serial-in data into parallel-out data. The microcontroller generates the sequence in which the LEDs are lit, thus creating the image.
The location of the display makes it pretty cool and the fact that it’s attached to this kind of fan makes the whole device completely silent, which is quite different from most POV displays out there that are rather noisy. Having a thing like this blinking in your living room might seem like a good idea if you want to impress a guest audience, but other than that I can’t find a reason for actually using it.
Silent Ceiling POV Display: [Link]