Persistence of vision (PoV) displays are super cool. They’ve been around for a long time, appearing in lots of inexpensive consumer goods like fans. Anything with rotary motion can act as a PoV display — yet I had never seen someone put one in a fidget spinner before!
This project uses an ATmega, some CR2032 batteries, 9 SMD LEDs and a TCRT sensor. Using the TCRT sensor is a very cool idea — it uses reflected IR to determine when an object is close. Because the user will have their fingers holding the center of the board, it’s an easy way to determine rotational speed without having to use something like a hall effect sensor and a magnet.
Persistence of vision works by rapidly turning the LEDs on and off at precise times during each rotation. Because the speed of rotation is quite fast, your eyes simply merge the light together and, if the LEDs are controlled accurately enough, you can have words and symbols appear “floating” in the air. If you’ve never seen a PoV display before, it’s a very neat effect.
Fidget spinners have come and gone in popularity, but if I owned one of these I think I wouldn’t be able to put it down! Because the Arduino source files are available, it’s easy to customize the messages you want to display or program in fancy patterns or symbols of any kind. This would be a great little toy to bring to a Maker Faire or other hacker gathering!
