Behold the wood-block wonder of the Kilopixel display

We're going out on a limb here... why not branch out from things like retina displays and get a little more fine grained?

Feature In a world where resolution, refresh rates, and frames per second can generate furious discussion, sometimes it's good to kick back and let a wood-flipping robot take the strain. Welcome to Kilopixel.

Kilopixel is a 40 x 25 grid of wooden blocks, each of which can be rotated to show a black or plain wood face. A user uploads a bitmap, and a robot arm laboriously rotates each block in turn to render the image.

The creator, Ben Holmen, came up with the concept six years ago. What the world needed was a large, inefficient display, with a web interface that anyone could interact with. In his blog explaining the device, Holmen said, "Compared to our modern displays with millions of pixels changing 60 times a second, a wooden display that changes a single pixel 10 times a minute is an incredibly inefficient way to create an image."

So, obviously, it had to be done.

But how? Holmen started off with a 21 x 3 pixel prototype to shake out some ideas. Instead of the wooden blocks he eventually settled on, he tried ping-pong balls (they didn't keep their shape) and painted Nerf balls (the paint eventually started to deteriorate).

A prototype made using nerf balls, which eventually deteriorated, click to enlarge – Image (c) Ben Holmen

And then there was the question of how to flip the pixels. First, he tried a LEGO wheel that could rotate the pixel and added a sensor to detect if the pixel was white or blank and stop the rotation accordingly. Then he tried using a solenoid to push the motor into the ball. But it was all a bit unsatisfactory.

Finally, after a couple of conversations with podcasters Joe Tannenbaum and Chris Morrell, Holmen decided that perhaps balls were the wrong approach and, instead, chose to use wooden blocks. He also decided to make the blocks himself. "This decision cost me a huge amount of time because doing things one thousand times takes forever," he wrote, "but I was really pleased with how it operated and looked."

Holmen was already familiar with CNC (Computer Numerical Control) machines and connected a CNC controller to a Raspberry Pi. The machine could then be instructed to move a "poker" to a given position, and a cube poked to rotate it. A light sensor was used to determine the physical state of the pixel.

It's a brilliant thing. Users can upload images, and after a while, the kilopixel renders the picture in all its blocky glory.

The completed woodblock display, click to enlarge – Image (c) Ben Holmen

Wooden blocks of the kilopixel device turned to create a display – Image (c) Ben Holmen

The device lurks in Holmen's office. The Register asked if it ever gets annoying, humming away to itself. Holmen replied, "I'm not annoyed by it yet, in fact it's really a joy to walk in to my office and see some art that someone else has created on my wall. It's a privilege!"

But asking the internet to come up with images… surely that's asking for trouble? Apparently not – Holmen said there'd been a few issues, but he'd been expecting worse. "I have a reporting mechanism built in case I need it, but I kept that hidden. So far there have been just a handful of tasteless or rude submissions. I've enlisted a few trusted friends to keep an eye on it and delete submissions as needed.

"Finally, I restrict submissions to people willing to log in with a Bluesky account, which is a pretty small pool of users. I expected worse, to be honest, and I'm prepared to address abuse if it does become a problem."

Youtube Video

Holmen told us he planned to leave the machine running for around two weeks, depending on how much maintenance it required to keep running. He also had no plans to make another: "Building one of these was enough of an effort," he told us, "This is a one of a kind device!"

And a marvelous device it is too.

Raspberry Pi supremo Eben Upton said of the project: "This is without a doubt one of the silliest (in the best possible sense) things I've ever seen someone do with a Raspberry Pi. Almost but not quite exactly not what we designed it for." ®