# HoloFans II (DD-700) > 'Hologram fans' are persistence-of-vision (POV) displays. A rotor carrying strips of LEDs spins fast while a controller switches each LED on and off at exact angles, painting one slice of the picture at a time. Because the eye blends these rapid flashes, the viewer sees a steady image that seems to float, especially against a dark background where the blur of the blades disappears. They aren't holograms in the physics sense. True holography records and rebuilds light waves using interference, usually with lasers. A fan draws a flat (2D) image, and the 3D look comes from the artwork's shading and the invisible frame. HYPERVSN, the brand formerly known as Kino-mo, describes its units as four LED rays spinning at about 670 rpm, and several units can be synced into a larger 'wall'. - Department: Tech (also Science) - First published: 2026-02-20 - Last updated: 2026-02-20 - Permalink: https://detailenjoyer.com/case/holofans-ii/ - Author: Marcus Easterling (DetailEnjoyer), The Detail Department ## Quick facts - **DD-700-F01**: A HYPERVSN fan spins four LED rays at about 670 rpm. _(Write-up · Exhibit E (Commercial units))_ - **DD-700-F02**: 'Hologram fans' draw a flat image and aren't true holograms. _(Write-up · Exhibit D (Not a real hologram))_ ## Write-up Floating figures, spinning blades. LED blades spin fast enough for your eyes to fill in the image. 1. **Painting with a spinning line**: A POV display has one or more LED strips on a rotor. A sensor tracks the rotor's angle, and the controller lights each LED at exactly the right moment to draw one 'slice' of the image per position. 2. **The eye does the rest**: The visual system blends flashes that arrive faster than it can separate them, so the slices merge into one continuous picture. 3. **Why it looks like it floats**: Against a dark background, the spinning blades are almost invisible, so the bright image seems to hang in the air. Shaded 3D-style artwork adds to the effect. 4. **Not a real hologram**: Holography records the interference pattern of light and rebuilds the light field, so you can look around the object. A fan draws a flat image on the plane of its blades. 5. **Commercial units**: HYPERVSN's manual describes four LED rays spinning at about 670 rpm. Units can be tiled and synced into larger displays for shops and events. ## Related case files - [HoloFans (DD-630)](https://detailenjoyer.com/case/holofans/): Part I of this series - [Photon Film (DD-067)](https://detailenjoyer.com/case/photon-film/): Another case about light and imaging hardware - [Print Precision (DD-005)](https://detailenjoyer.com/case/print-precision/): Another case about precisely timed tech ## Reel vs. record - **Not a hologram**: the image is drawn by LEDs on the plane of the blades. True holography rebuilds light waves using interference. - **Note**: Not truly 3D: a single fan makes a flat image that only looks 3D because of the artwork's shading and the invisible blades. - **Mechanism**: a sensor tracks the blade angle, and the controller fires each LED at exact angular positions, which is how the 'precise sequences' are timed. - **Wording**: 'persistence of vision' is the popular term. Perception researchers describe the effect as flicker fusion and the eye's temporal integration. - **Missing safety note**: commercial units spin fast and are usually mounted high or behind a guard, because the blades are a contact hazard. ## Video: HoloFans II: Floating Figures, Spinning Blades - Duration: 22.7 s · Published: 2026-02-20 - File: https://detailenjoyer.com/assets/videos/DU_NtlgkX4K.mp4 ### Transcript DID YOU KNOW? Persistence of vision hologram fans are display devices that create the illusion of floating 3D images by rapidly spinning LED-equipped blades in a circular pattern. As the blades rotate at high speed, individual LEDs switch on and off in precise sequences, and because the human eye briefly retains visual information, known as "persistence of vision", the flashes blend together into a continuous image suspended in midair. NOW YOU KNOW! ## Questions & answers **Q: What makes the image in a 'hologram fan'?** A: LEDs on spinning blades. _(Source: Write-up · Exhibit A (Painting with a spinning line) · Circuit Cellar: Build a Persistence-of-Vision Display; invidis (2018): The tech behind those furiously-spinning LED holograph-ish HYPERVSN walls)_ **Q: Is a hologram fan a true hologram?** A: It's a persistence-of-vision display. _(Source: Write-up · Exhibit D (Not a real hologram) · Wikipedia: Holography; invidis (2018): The tech behind those furiously-spinning LED holograph-ish HYPERVSN walls)_ **Q: About how fast does a HYPERVSN rotor spin?** A: About 670 rpm. _(Source: Write-up · Exhibit E (Commercial units) · HYPERVSN operating manual; invidis (2018): The tech behind those furiously-spinning LED holograph-ish HYPERVSN walls)_ **Q: Why does the image seem to float?** A: The fast-moving blades become almost invisible. _(Source: Write-up · Exhibit C (Why it looks like it floats) · invidis (2018): The tech behind those furiously-spinning LED holograph-ish HYPERVSN walls)_ **Q: What tells the controller when to fire each LED?** A: LED timing is tied to the rotor's position. _(Source: Write-up · Exhibit A (Painting with a spinning line) · Circuit Cellar: Build a Persistence-of-Vision Display; invidis (2018): The tech behind those furiously-spinning LED holograph-ish HYPERVSN walls)_ ## Sources - [invidis (2018): The tech behind those furiously-spinning LED holograph-ish HYPERVSN walls](https://invidis.com/sixteen-nine/2018/07/04/the-tech-behind-those-furiously-spinning-led-holograph-ish-hypervsn-walls/) - [HYPERVSN operating manual](https://hypervsn.com/media/AFU/Operating_manual.pdf) - [Circuit Cellar: Build a Persistence-of-Vision Display](https://circuitcellar.com/archive-article/build-a-persistence-of-vision-display/) - [Wikipedia: Holography](https://en.wikipedia.org/wiki/Holography) ## Cite this case file Easterling, Marcus. "HoloFans II." The Detail Department (DetailEnjoyer), case file DD-700, last updated Feb 20, 2026. https://detailenjoyer.com/case/holofans-ii/