The principle is that there is a row of light-emitting diodes on the fan blades. When they rotate at high speed and flash, due to the persistence of vision, what we see are arc-shaped line segments. If a microcontroller is used to control the timing and time of the diode flash, various patterns or text can be formed.
The pattern change of the LED display fan can be controlled by the following factors:
1. The initial phase of the LED light
2. The rotation speed of the fan
3. You can now know the position of the LED lights at a certain moment. As long as you light up different LED lights at different positions, you can finally form a complete pattern.
The flicker of a string of LED lights may be severe, but as the number of strings increases, the flicker will gradually improve. The reason why we can see the 3D floating image projected on the blades is because of people. The phenomenon of persistence of vision (POV). .
Extended information
Led display fan visual persistence phenomenon:
When the human eye observes the scene, the light signal is transmitted to the brain nerves, and it takes a short period of time time, after the effect of light ends, the visual image does not disappear immediately. This residual vision is called "after-image", and this phenomenon of vision is called "visual persistence".
When the LED display fan is moving rapidly, after the image seen by the human eye disappears, the human eye can still retain its image for about 0.1-0.4 seconds. Because there are no borders and no fixed screen, the animation looks like it is suspended in the air, which is very realistic. And there is a wifi module so we can update content and control editing remotely.
People's Daily Online-CES 2018: "Electric fan" can display floating images