Show HN: I spent 6 years building a ridiculous wooden pixel display
49 comments
·August 4, 2025rexreed
This is cool. I wonder, as you were iterating on the design and development, why didn't you start with a very small grid (10x10) to validate or test different options for their practicality and operation before scaling up to the 1000 pixel versions? It might have saved a lot of time and money, but maybe small scale tests aren't sufficient to work out the kinks?
re
Really cool! I just watched it finish "cat saying 'hi'". It doesn't look like any new posts have shown up on @kilopx.com on Bluesky for the last 9 days though.
A few suggestions for improvements:
- After completing a submission, move the "pen" out of the way as much as possible to get a clean photo of the completed art before moving onto the next submission.
- On the website, show attribution for the currently in-progress submission.
- On the website, have a "history" gallery for completed submissions. It looks like pending submissions have permalinks that say "Timelapse will be available after this is drawn", but there's no way to discover permalinks for completed submissions (or the in-progress one).
fentonc
Awesome project! I built a somewhat similar 30-pixel display: https://www.chrisfenton.com/the-pixelweaver/
Mine was entirely mechanical (driven by punch cards and a hand-crank), and changed all of the pixels in parallel, but a lot of the mechanism development looked extremely familiar to me.
benholmen
This is incredible! I can appreciate how much work it took to make this happen. Well done!
I was recently in the presence of some linotype machines from the 1800s and it's so good to be humbled by the achievements of people who came before us. That machine was so complex, I could barely begin to figure out how to manufacture one. Your discussion of looms reminds me of that!
xpe
Another idea: have the cubes point an edge straight forward (instead of a face). Then if each cube has two adjacent dark sides and two adjacent light sides, one could setup two ‘simultaneous’ images: one viewed from the left at 45° and another viewed from the right. (Each pixel would have four possibilities.)
boothby
Similarly, the camera could stay face-on and double the pixel count with largely the same hardware.
derefr
Speaking of "alternatives to e-ink for a zero-power-use-when-not-updating dot-matrix display"...
Has there ever been designed a "display" that is just a thermal printer hidden in one end of a box, and a take-up spool + tensioning spring hidden on the other end, such that the "display" is then a continuous thermal paper "scroll" stretched across the box behind class, that can be "refreshed" by printing a new full-width image to the thermal printer?
(I feel like this would be especially neat because the resulting display could be really long. Not very wide, though—I don't think you can get thermal paper rolls much wider than standard receipt-printer size. Correct me if I'm wrong!)
turtlebits
Not sure if you can call it a display if you have to throw it away to change an image.
daotoad
If you wanted to take this a little further, you could cover the "display" with heat erasable ink like is used in a Pilot Frixion pens.
This ink is interesting in that it fades when heated (60 C), but darkens when cooled (-10 C). In between those temperatures it is stable.
Thus you could have one loop that is continuously reused. Not sure how many cycles you can get before the ink degrades.
cgriswald
Allow me to correct you: Some fax machines use thermal paper so your display can be at least 8.5".
tristor
Ooh, I like this idea. You could also use the box structure to stretch the display so it has 4 sides if you build the mechanism correctly, which means as you refresh the image on the "primary" display it moves the other images to the secondary, tertiary, and quaternary displays before it gets taken up. You can use tensioned rollers at each corner hidden by the frame if you plan for a gap for "bezel".
aarondf
This has to be the the most expensive cost per pixel display I've ever seen. And I've never loved a display more. This is absurd in the best possible way
Rexxar
And absolutely no energy consumption when you don't change the image.
benholmen
I don't think I want to think of the actual cost per pixel - especially the cost of my time! I have deliberately avoided accounting the final cost
zahlman
For what it's worth, dollar stores typically sell wooden cubes for arts & crafts purposes (board game designers also like them for prototyping) in bags that work out to a few cents per piece. I guess they're quite a bit smaller than what you ended up using, though. And of course that doesn't account for the frame or the control mechanism. (And now you have me trying to think of more robust ways to turn the pixels...)
saltcured
I keep trying to imagine "faster" variations.
What about some system to shoot wooden spheres into a tube or channel for each scan line, selectively feeding different color spheres. Some combination of gravity or pneumatics to drive it. So a scan line would flush out one end and refill from the other. Then scale it up to a stadium size unit with bowling ball pixels.
I guess a challenging part would be proper timing to recycling the colors back into their appropriate supply channels. And also introducing some kind of damping to quiet it down and reduce the wear and tear on the pixels.
On the other extreme, you could go active matrix and have blocks that simply rotate in place to show different face colors based on some solenoid/servo action.
rented_mule
Your idea is not too far from marble pixel art machines... https://youtu.be/w1ks0Vy98KI
jstanley
Hah, cool, I had an idea for a similar project (although I'm not crazy enough to make 1000 pixels, or a robot to turn them for me). But I got as far as making a JavaScript simulation and realised I couldn't be bothered manually turning the beads https://incoherency.co.uk/beadboard/
xpe
You could order the presentation of a set of images by some distance metric :)
- naively: Levenshtein
- better: real world edit time based on a model of the display : probably dominated by XY travel distance
munificent
I was wondering about the algorithm to drive the plotter and update pixels, which ties into this.
Given the current image being shown and the next image, you (presumably) want to plot the pixels of the next image as quickly as possible. I believe the optimal algorithm is:
1. Calculate the set of pixels that are changed between the current and next image.
2. Find the shortest path from the plotter's current position through each of those pixels. I believe breadth-first search (O(n)) is sufficient here.
Running this on all potential upcoming images and choosing the one with the lowest total path cost would do what you propose under "better".
cinntaile
There was a fish project on here a few days ago that also had to deal with uh... adverserial images and it was (mostly?) solved by training a neural net to detect those.
benholmen
TTFP will surely be < 1 day
mosdl
Really cool and it would totally work for a restaurant/coffee shop.
benholmen
I think I might put this in my friend's coffee shop but I'll restrict access to people in the coffee shop. Not going to let the internet get a hold of that.
In addition to the user-controlled modes I also have ambient modes. My favorite is a clock that struggles to draw the current time because it takes too long
boredpudding
This used to exist! I remember a video about this large analog billboard in Amsterdam (?).
Unfortunately I can't find the video. Will edit if I do (or anybody else finds it first).
smokel
Perhaps you are thinking of Daniel Rozin's "Wooden Mirror" (1999)?
boredpudding
That's a very good one, but in my case it was a huge billboard that was advertising movies and stuff.
It had cubes in different colors so from further away it would look like an image.
benholmen
Rozin was a direct influence on me! Seeing his stuff ~10 years ago got me thinking about unorthodox displays.
I built the world's most impractical 1000-pixel display and anyone in the world can draw on it. It draws a single pixel at a time and takes 30-60 minutes to complete a single image. Anyone can participate in the project by voting for the next image to be drawn, and submitting images.
https://kilopx.com/