The Persistence of Vision globe display built with a Raspberry Pi produces a 360 degrees image from rotating LED lights. Producing a great effect such as a holographic looking Star Wars Death Star as well as video and games.

The Persistence of Vision (POV) display makes use of the fact that the human brain holds the last image we see briefly. Inside the POV globe is a single ring of LED's basically connected to the HDMI display of a Raspberry Pi mounted on the ring. The LED's change colour to match one vertical pixel column of a displayed image at a time until they have displayed all the columns that make up the image. When this is done you see just a load of LED's changing colour but when the ring is spun at speed your brain sees all the colour changes as the LED's move and builds up a solid image which is what you see.

A team at the School of Electronics & Electrical Engineering at the University of Leeds built the POV globe as a Raspberry Pi display which uses a HDMI decoder board to change the colours of connected LED's. As the Raspberry Pi is mounted in a rotating ring, it is controlled remotely from a Ipone/Ipad app.

This gives the effect of a holographic globe reminiscent of the battle plan scenes in Star Wars so seeing the Death Star produced this way looks cool for Star Wars fans. Anything that the Raspberry Pi can display can be shown on the POV globe including video and games though the resolution is a fraction of what the RPI can display at 360 x 168 pixels with a frame rate of 10 fps. This is not a new concept and has been done with displays in the past but the fact this one uses a Raspberry Pi makes it a possible project for anyone who want to give it a go.

See the Interactive Persistence of Vison blog to get full details on how they put the pov globe together. The Blog includes a gallery of images they have used the display for, which includes showing a map of the world, rotating text, the Raspberry Pi logo, a BBC Top Gear episode on the Iplayer.


Images by Tom Carpenter



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