James Brown Publishes a Bill of Materials for His Impressive Volumetric POV Display

If you fancy building your own — and the terrifying high-speed spinning RGB LED matrices haven't put you off — here's a shopping list.

Gareth Halfacree
4 months agoDisplays / HW101

Maker James Brown has offered a bill of materials (BOM) for his latest rapidly-spinning volumetric 3D display, powered by a Raspberry Pi 4 and a pair of RGB LED panels, for those looking to follow his footsteps in the world of 3D persistence of vision (POV).

"Someone building their own voxel display got in touch asking for the BOM and I thought that might be of interest generally," Brown writes of the components list. "It's a collection of things I had or could easily get in New Zealand, rather than necessarily the best part for the job. If I made another, I would change some of it (lazy Susan bearing, finer pitch LED modules, shorter motor) but this configuration has at least been shown to work."

Brown has been experimenting with spinning 2D displays to create a 3D effect for some time, most recently building a higher-resolution volumetric display capable of rendering recognizable characters from Id Software's Doom. It's this for which Brown has listed the components, including its globular housing: a 400mm acrylic globe originally designed for garden lights.

Elsewhere in the build, a pair of 128×64 RGB LED matrices are connected to a Raspberry Pi 4 Model B single-board computer. "Just needs something with Wi-Fi," Brown notes, "and enough RAM for the voxel buffer."

The display's depth effect is truly impressive, but that 2mm acrylic isn't just for show — the spinning LED panels are a worry. (📹: James Brown)

There's a custom interface to the LED matrices, a photointerrupter on one of the Raspberry Pi's general-purpose input/output (GPIO) pins for synchronisation, a slip ring built from alternator parts, a "no brand speed controller," timing belt, 115mm bearing, a counterweight of window lead, and a 100W 12V PSU.

"[The motor controller] will be replaced by a motor driver," Brown writes of a future revision of the display, "connected to a microcontroller communicating with the spinning [Raspberry] Pi via Bluetooth."

Brown's full BOM is available in this Mastodon thread.

Gareth Halfacree
Freelance journalist, technical author, hacker, tinkerer, erstwhile sysadmin. For hire: freelance@halfacree.co.uk.
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