Glowing and blinking things are some of our favourite projects around these parts, and the bigger, the better. [Thomas] wrote to us recently to share the design and construction of a large LED wall at the Oregon Museum of Science, and the results are nothing short of impressive.
The concept involved a large LED wall that would be completely hidden when switched off. The team decided to approach this by hiding high-brightness LED panels using APA102 strings behind milky-white plexiglass panels covered with a woodgrain print. The screen has a total of 90,000 pixels, arranged in a 408×220 resolution display.
A lot of bespoke LED displays have some pre-coded patterns, or perhaps some basic reactive features. In this case, FPGA grunt was brought to bear on the problem and the display accepts standard HDMI input. Four Spartan 6 Mojo FPGA boards split up the task of addressing the panels, each receiving the same HDMI signal, but only crunching the pixels relevant to their area of the display. To make sure clean SPI signals get to each panel, special RS485 driver chips are used to send the signal over a differential pair from the FPGA, before breaking the signal back out to standard SPI at the destination.
Building such a large display takes special techniques, and [Thomas] notes that the help of a local construction company was imperative to making the construction of the final video wall look easy. It’s always interesting to see what goes into these large installations. Sometimes, a major build can even clear out world stocks of important components.
I’m not sure why the author does this, but the “I” in OMSI is “Industry”. And the acronym form of the name is the more used and recognizable one.
FWIW: I wouldn’t have had a clue what it is if the author had only referred to it as ‘OMSI’, it’s certainly curious that the ‘and Industry’ was missed out though. Presumably they were interacting with people who run the museum, so maybe they referred to it as ‘Oregon Museum of Science’?
The folks who run OMSI almost universally refer to it as “OMSI” (note: you pronounce it like a word, Awm-Zee, not saying each letter, O-M-S-I like my California transplant friends did when they first moved here).
However, for the sake of an article for those not local, typing it out as Oregon Museum of Science and Industry makes more sense.
got it changed. My mistake. – thomas
Wood grain paneling and a trick hidden display!
So where’s “Our Man Flint” ?
Short road trip seems to be in order! By short I mean 45 minutes, time to round up the curtain climbers and go play.
Very nice, looks like it’s being projected on a wall, here’s a link to a video…
https://photos.google.com/share/AF1QipPYQJqs3yIWY1aVAFIXrs4XjTi-gNdBH7gJE4NuvuNp6Dpf-QK31mDaRgchTlBmqg/photo/AF1QipPiIwIZFsOk7hCIRc5a77yIhQC79pLUGH-jl4vB?key=T2FCV1Etckc5LVVuMjlRLXVjNjh1VzZyMy1TcU1n
Also I’d like to see this deployed with only IR LEDs, nothing to the eye, amazing on your phone.
That sounds cool. Interesting idea in fact. The wall behind the wood grain plastic on the other hand seems like it would dim down and screw up the color balance of the led’s.
Not really my idea, some guys have done something similar and I’m sure I say it on HAD but since I couldn’t find it here’s a link to Gizmodo.
https://gizmodo.com/take-a-picture-hides-infrared-artwork-in-plain-sight-5777844
Hm. I need just such a HDMI chunking solution for a project I am working on myself, I’ll have to study this a bit.
I hope it’s expandable to 350,000 LEDs. For, um, no reason.
https://hackaday.io/project/27799-barco-nx-4-group-reversing-adventure