You’ve probably seen a spinning fan or display with LED lights that forms text or images in mid-air — it looks like magic! But what’s really happening?
This amazing effect is based on a concept called Persistence of Vision (POV). When an LED strip spins fast enough and its lights turn on and off at just the right times, your brain blends those quick flashes together. The result? You see a complete image - even though it’s really just a single line of lights moving in circles!
Persistence of Vision is a visual phenomenon where an image stays in your brain for a brief moment after it disappears. This is the same principle that makes movies possible - you see around 24 still frames per second, but your brain blends them into smooth motion.
In simple terms: your eyes “remember” an image for about 1/10th of a second (100 milliseconds).
Now imagine an LED strip with a single row of lights spinning quickly in a circle:
The strip lights up different LEDs at different moments as it spins.
Because it’s moving fast, each LED’s light appears in a slightly different spot around the circle.
Thanks to persistence of vision, your eyes blend these spots together into a complete image or pattern.
It’s like the LED strip is painting an image in the air one line at a time - and your brain fills in the rest!
To make this illusion work, the microcontroller (like an Arduino) must:
Measure the rotation speed — often using a Hall Effect Sensor and a small magnet.
Turn specific LEDs on and off at the exact right angles as the strip spins.
Repeat this process quickly enough so the image appears solid and stable.