[HN Gopher] I made a small LED panel
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       I made a small LED panel
        
       Author : Brajeshwar
       Score  : 142 points
       Date   : 2025-10-09 15:31 UTC (12 days ago)
        
 (HTM) web link (www.stavros.io)
 (TXT) w3m dump (www.stavros.io)
        
       | mytailorisrich wrote:
       | The diffuser really makes this. The resulting effect looks great.
        
         | stavros wrote:
         | It really did! It looked much better than I hoped, I really
         | liked the result.
        
       | stavros wrote:
       | I was about to comment that I _also_ made a small LED panel, but
       | then realized it was me.
       | 
       | Here's the latest LED thing I'm working on (the design isn't
       | mine): https://immich.home.stavros.io/share/oXerU8gnLn-
       | dNHunPOg8lM8...
        
         | BolexNOLA wrote:
         | spidermanspointing.jpg
         | 
         | Jokes aside this is super cool. I always find LED panels really
         | interesting to look at under the hood. I'm so picky about the
         | ones I like to use almost purely based on vibes when filming.
         | They're just one of those things that you immediately know
         | you're going to love or hate in post the moment they hit your
         | subject
        
           | stavros wrote:
           | What can I say, I'm addicted to LEDs. I tried so hard to not
           | make that cube above, but I failed.
        
             | BolexNOLA wrote:
             | Pretty cool way to fail
        
               | stavros wrote:
               | All credit goes to
               | https://www.printables.com/model/337027-cubled-led-
               | cube-8x8-...
        
             | MomsAVoxell wrote:
             | Did you ever try to use LED's as an input device?
             | 
             | My next LED cube project will be oriented towards trying to
             | do that.
        
               | stavros wrote:
               | How do you mean? Like the magnetometer above? LEDs are
               | outputs, no?
        
               | MomsAVoxell wrote:
               | Not always, they can be configured to behave as
               | photodiodes, too:
               | 
               | https://www.codrey.com/electronics/the-led-photodiode-
               | trick/
               | 
               | This is also in my "TODO" list, maybe with the next
               | magicShifter revision, or possible once I get the current
               | new design booted and refactored, a bit ..
               | 
               | https://www.instructables.com/LEDs-as-light-sensors/
        
               | stavros wrote:
               | Ahh ok, you don't mean WS2812s then, just plain LEDs. I
               | don't really have any ideas for what to do with a
               | photodiode, but I have some of those straight LEDs and I
               | really want to make something with those.
               | 
               | What kind of thing would you want to make with LEDs as
               | inputs?
        
               | MomsAVoxell wrote:
               | MIDI things. :)
        
         | Lerc wrote:
         | Do you know if the panels can be bodged to be non square? There
         | shouldn't be a lot of fancy wiring to screw up if it's all
         | WS2812. Can you (delicately) chop a few LEDs out and bridge the
         | connections?
         | 
         | (hoping I have seeded this idea, so I'm not the first one to
         | attempt this)
        
           | stavros wrote:
           | Sure, you can connect the LEDs together however you like (am
           | I misunderstanding the question?).
        
             | Lerc wrote:
             | Theoretically you can. It's whether it all goes pear shaped
             | when you take a Dremel to the board to make it
             | OO    OOOO   OO         OO    OOOO   OO         OO    OOOO
             | OO         O    OOOOOO   O         O    OOOOOO   O
             | O    OOOOOO   O             OOOOOOOO             OOOOOOOO
             | 
             | And how fiddly it is to stitch up the edges. I shall find
             | out in a couple of days when the panels arrive.
        
               | stavros wrote:
               | Oh that's what you mean! Yes, you can, but you'd have to
               | bridge all the data connections by hand. Much easier to
               | just leave those LEDs off in software.
        
           | tiku wrote:
           | Perhaps a stupid question but why not just not use those
           | LEDs? Shut down in the software..
        
             | bombcar wrote:
             | Because you want the panel to fit a non-square shape, with
             | no room for "leftovers" - think making it round to fit in a
             | doorknob hole or oval to go in place of a car brand badge,
             | etc.
        
               | stavros wrote:
               | In that case, it would definitely be much cheaper to
               | design a custom PCB and get it assembled. It would
               | probably take you much less time than all the cutting and
               | soldering.
        
           | ramses0 wrote:
           | I mean... as a lay-person, you've got point-lights and his
           | isolation/diffusion layers in between. If you're 3d-printing
           | your diffusion-thingy, then you've got tons of room to play
           | games with the shape of the final glow. Even moving light via
           | '265mm with 64 Fiber, Optical Grade Plastic Light Guide' if
           | you're not hitting the corners well enough.
        
             | Lerc wrote:
             | That... is a really good idea. I was thinking of cutting a
             | flat piece of diffusing material to shape.
             | 
             | My intuition is that there would be pain in 3d printing a
             | diffusion structure because slicers etc. would not be
             | optimised for producing a homogenous solid. I would guess
             | that 100% infill is actually something like 99.98% with
             | tiny voids that stick out like a sore thumb when you shine
             | a light through. I might be wrong about that, I'm not a 3d
             | printing expert.
             | 
             | The principle of reshaping I think is awesome though. It
             | might just be an issue of modulating brightness to counter
             | any uneven distribution. It's got me thinking about a
             | Faceted approach. 3d Print a faceted basin and then print a
             | thin edge divider to sit in it. Fill it with something that
             | sets solidly enough and makes a good diffuser (this too
             | sounds like a war with bubbles). Take it out of the basin
             | when set and you potentially have a nice faceted surface
             | with each facet individually colourable.
        
           | sokoloff wrote:
           | I think you'd be far better off to make a custom PCB in
           | whatever shape you like from the like of JLCPCB, PCBWay, or
           | others.
           | 
           | The WS2812s here all connect to each other in series, so if
           | you cut the board down, you'll have to replace the cut
           | connections with bodge wires. To my mind, that plus the
           | cutting is way more work than just making a PCB in exactly
           | the shape you want.
           | 
           | You can get cheap PCBs for $5-$6 for qty 5 100mm x 100mm
           | boards delivered to your door in the US. Add on LEDs at $0.03
           | to $0.05 each and I'd way rather make than modify here.
        
         | phil42 wrote:
         | How did you connect the individual smaller LED panels together?
         | I guess the cool color patterns and the individual addressing
         | comes from WLED then?
        
           | stavros wrote:
           | There's a photo of the panels connected to each other, each
           | panel has three input and three output pads, and you solder
           | those together. The software just sees one long strip, and
           | you configure the shape of it so it corresponds to what you
           | have in reality.
        
         | MomsAVoxell wrote:
         | Nice work! I've done a few LED thingies too ..
         | 
         | https://magicshifter.net/
         | 
         | .. and, I recycled some old scoreboard display panels to make
         | something similar to your latest project, also:
         | 
         | About the panels: https://metalab.at/wiki/Blinkofant/LED-
         | Display_History
         | 
         | The Blinkophant: https://i.imgur.com/3aPytEp.jpeg
        
           | stavros wrote:
           | This is great! Your TLS cert is invalid, though, so the site
           | doesn't load properly, I think.
        
             | MomsAVoxell wrote:
             | Yeah, expired a while ago, its a pretty old site and we
             | have to get the old gang back together to fix it.
             | 
             | Thanks for checking out the magicShifter3000!
             | 
             | I've got a new one designed, currently in prototyping
             | stages .. a bit more powerful and a lot more oriented
             | towards audio/synthesis. Same form-factor, and probably
             | MS3000 and midiShifter will have an ecosystem ..
        
               | stavros wrote:
               | If you have the site on GitHub, you can deploy it to
               | Cloudflare Pages with a few clicks, and it will take care
               | of all of that stuff for you.
               | 
               | Also, a few friends and I have a maker Discord server and
               | you'd fit right in, I can send an invitation if you like!
               | My email is in my profile.
        
               | MomsAVoxell wrote:
               | Server: not my department. :)
               | 
               | But yeah, we'll probably reboot magicShifter soon ..
        
           | tecleandor wrote:
           | Where did you get the scoreboards? eBay?
        
             | MomsAVoxell wrote:
             | Donated to metalab through a member connection.
             | Austria/Vienna has a bit of a 'recycle/re-use/repurpose'
             | scene, and this was an early example of a metalab win:
             | 
             | https://metalab.at/
             | 
             | We devoured the panels and did all kinds of funky things
             | with them.
             | 
             | https://metalab.at/wiki/Blinkofant/LED-Display_History
        
           | stavros wrote:
           | I made something close to MagicShifter a while ago, I didn't
           | add an accelerometer, though:
           | 
           | https://www.stavros.io/posts/behold-ledonardo/
           | 
           | I would really like to make it work with an accelerometer, as
           | right now it's a bit fiddly to get the right speed for
           | images, but I don't know if I can make it work.
        
             | MomsAVoxell wrote:
             | Not just accelerometer, but magnetometer too. :)
             | 
             | This means you can basically use the magicshifter3000 as a
             | knob. Or, a slider.
             | 
             | Its very fun with MIDI.
             | 
             | :)
        
               | stavros wrote:
               | Oooh fantastic! That's the kind of thing I really like to
               | see.
        
               | MomsAVoxell wrote:
               | Perhaps you will understand what this is, then:
               | 
               | https://www.youtube.com/watch?v=syP8_lccIQA
               | 
               | :)
        
               | stavros wrote:
               | Haha, amazing! Is it based on the accelerometer, or do
               | you have a microphone connected somehow? I can't tell
               | whether you're tapping the desk they're on.
               | 
               | Then again, the right ones light up more than the left
               | ones, so I think you're tapping on the right edge of the
               | desk. Very cool!
        
               | MomsAVoxell wrote:
               | The accelerometer and the desk, being tapped by me
               | offscreen just to be sure things were responding .. alas,
               | they are kind of hard to keep in one big pile, but yes
               | very fun to play with en masse! :)
               | 
               | (This was some years back, note.)
        
       | scottbez1 wrote:
       | On the topic of small LED panels, Jason of Evil Genius Labs has
       | been making some _really_ small LED panels [0] with addressable
       | 1mm x 1mm LEDs (yes, individually addressable AND only 1mm on
       | each side!). Fitting 128 onto a 1 " circle is pretty sweet.
       | 
       | I keep meaning to design some PCBs with them [1] but it's too far
       | down my ever-growing list of projects to see the light of day...
       | 
       | [0] https://www.evilgeniuslabs.org/one-inch-fibonacci128
       | 
       | [1] https://www.lcsc.com/product-detail/C5349953.html
        
         | stavros wrote:
         | Why are you doing this to me
        
         | karlkloss wrote:
         | https://spotpear.com/shop/ESP32-S3FH4R2-Matrix-8x8-RGB-LED-W...
        
           | zokier wrote:
           | Those look like normal 2.5-3mm LEDs, that is big difference
           | to 1mm2 LEDs. The circle disc from OPs link has 2.5x higher
           | LED density, and they could be probably packed even more
           | densely in a grid.
        
         | alias_neo wrote:
         | Ah, the joy of being a Brit. That first link is just full of
         | purple rectangles containing the text "content not viewable in
         | your region" (Imgur).
         | 
         | I'm feeling safer already. _sigh_.
         | 
         | Looks like a fun site though, I'll take a look when I'm not on
         | my work computer.
        
         | wkat4242 wrote:
         | Those are just really small WS2812, I get those at 160 led per
         | meter on a strip of 5 bucks per meter. I just mean to say they
         | are cheaply available in many form factors. I use them a lot in
         | cosplay clothing.
        
         | zokier wrote:
         | Kingbright recently released 01005 (0.45mm x 0.25mm x 0.2mm)
         | sized LEDs, which afaik are one of the smallest ones easily
         | available. One neat idea would be to pack those on DIP14 sized
         | pcb, making tiny neat character display. I guess something like
         | 5x7 or 6x8 matrix could be doable with small mcu to drive them.
         | 
         | For those 1mm addressable RGB LEDs I've been thinking how you
         | could do cool cyberpunk looks by stringing them on some
         | hairthin magnet wire and sticking them on your
         | body/face/hair/etc. Blend them in with some latex or something
         | if needed. Just need to hide the controller/battery somewhere.
        
       | nikkwong wrote:
       | This is neat! Any notes on the algo for controlling the output of
       | the ws2812s?
        
         | Tempest1981 wrote:
         | Maybe WLED plasma effect (number 97)?
         | 
         | https://kno.wled.ge/features/effects/
         | 
         | https://github.com/wled
        
           | stavros wrote:
           | Yes, it's probably something like that. WLED has a ton of
           | patterns, it's really nice.
        
       | Lerc wrote:
       | I have a bunch of these 8x8 panels on their way from AliExpress
       | right now for an art project that a part will look remarkably
       | like the video. V1 will probably be a 32x32 just like it.
       | 
       | I still haven't decided if I want to have a partition grid
       | between the panel and the diffuser to make square edge pixels.
       | It's definitely going to have a rp2350 inside. PIO is the best
       | thing ever.
        
       | karlkloss wrote:
       | https://kno.wled.ge/
        
       | MrGilbert wrote:
       | Speaking about small led panels, I also recommend the "Fluid
       | Simulation Pendant" from mitxela:
       | https://mitxela.com/projects/fluid-pendant
        
         | stavros wrote:
         | Mitxela is on another level though, it's not fair.
        
           | MrGilbert wrote:
           | Life ain't fair. Take it as a compliment and a challenge! <3
        
             | stavros wrote:
             | I will make another small LED panel with ONE MORE LED!
        
       | Havoc wrote:
       | Tried my hand at this too. Except more janky and was aiming at
       | lots of output.
       | 
       | LED get freaking hot fast at higher wattages and quickly found
       | myself dealing with heat sinks etc.
        
         | stavros wrote:
         | Do you need to run them at max brightness? I run them at 10% or
         | so, they're _really_ bright.
        
       | smusamashah wrote:
       | I dont understand it. The resolution is only 8x8. How does the
       | animation at the end looks so smooth and way higher resolution?
        
         | stavros wrote:
         | The diffuser fakes the resolution, basically, by blending the
         | colors together physically.
        
           | smusamashah wrote:
           | I believe you, my brain doesn't. Those movements are so
           | smooth. The line where two different colours merge have no
           | sharp edges and look perfectly curved. Only thing edgy was
           | the very last blinking animation where there weren't any
           | colours.
           | 
           | Thinking more, if there were only 4 LEDs I can imagine how
           | they would look like diffused.
           | 
           | Initially I was thinking if 8x8 can show all those smooth
           | details and motions, can it be used to show any other higher
           | resolution imagery instead of just moving colours.
        
             | stavros wrote:
             | I think the thing that fools us here is the fact that we're
             | used to pixels being discrete, so it doesn't "look" low-res
             | because the colors blend into each other. If you imagine
             | that each LED produces a small circle onto the diffuser,
             | and that this circle overlaps the ones around it a bit, it
             | gets easier to see through the illusion.
             | 
             | It's much easier to understand when you can change the
             | distance of the diffuser to the panel (which I did when
             | testing), because then you can see the lights go from
             | little squares with lots of dark space around them, to
             | this, to big blobs of one color.
        
             | dekhn wrote:
             | A diffuser is basically applying a convolution to the
             | underlying pixel array (moving the diffuser away from the
             | LED increases the convolution width, but unfortunately also
             | reduces the intensity).
             | 
             | I don't think you can exploit that to show something higher
             | resolution than the original pixel array,
        
       | masto wrote:
       | LED matrix panels are tons of fun! I strung a bunch of them
       | together to make a marquee across my basement soffit:
       | https://youtu.be/W0_3rzvq9Ks?si=aTT_uOZfOYh9NLUi
       | 
       | I have to resist the urge to tile every surface with blinky
       | lights. I think part of the appeal goes back to why I enjoyed
       | writing programs on my C64 to bounce my name around the screen.
       | It's a limited playground, and limitations inspire creativity.
        
         | stavros wrote:
         | This looks fantastic. Your basement really has a nice aesthetic
         | to it, and that marquee looks great in it!
        
       | cantalopes wrote:
       | I wonder what material is diffuser made of
        
         | stavros wrote:
         | It's just this:
         | 
         | > a two-layer white square out of PLA
        
       | foofoo12 wrote:
       | For the diffuser, there's a nice one or two in all LED/OLED
       | monitors. More stuff in there too, acrylic/polycarbonate glass
       | and a Fresnel lens. Worth scavenging if you come across a broken
       | one.
        
         | stavros wrote:
         | Oh that's a great idea! This also reminds me of the video where
         | the guy took out the LED panel and used just the light and the
         | Fresnel lens to make a window with very natural-looking light.
        
         | mortenjorck wrote:
         | I think you mean "LCD/LED" monitors (where "LED" is commonly
         | used to mean an LCD panel with an LED backlight, and "LCD" is
         | used to differentiate old CCFL-backlit LCD panels).
         | 
         | OLED screens do not have a backlight and thus don't have a
         | diffuser.
        
           | foofoo12 wrote:
           | Whoops, guilty as charged. Thanks.
        
       | Nevermark wrote:
       | For a second I thought this was about custom LED construction.
       | 
       | But apparently, LEDs require advanced processes unlikely to be
       | available for makers, anytime in the near future.
       | 
       | However, Zinc sulfide phosphor mixed into epoxy can be used to
       | make voltage activated luminescence. For some interesting
       | guidance on "doping" for color, I present a 1953 patent:
       | 
       | > zinc" sulphide' activated by both copper ad manganese in
       | accordance, with the present invention is strongly
       | electroluminescent, the addition of. manganese to the copper-
       | activated material resulting in a shift in the color of
       | luminescence toward the red end of the spectrum. Thus, the
       | materials of the invention, when excited by a fluctuating
       | electric field, show colors of luminescence ranging from bluish-
       | green through shades of bluish-white, pinkish-white and yellow to
       | orange. [0]
       | 
       | Looks like some level of RGB was possible from the get go.
       | 
       | [0] https://patents.google.com/patent/US2743238A/en
        
         | jononor wrote:
         | Cool! What kind of voltage ranges are we talking, and how toxic
         | is Zinc sulfide phosphor?
        
           | Nevermark wrote:
           | Not that toxic, unless inhaled (take precautions) or
           | ingested, or heated to high temperature, which produces a
           | toxic gas.
           | 
           | Doping of course can change that.
           | 
           | May require 100+ V AC at 500-2000 Hz. So probably not the
           | right element to implement 4k in! Or for an early education
           | science experiment, unfortunately.
           | 
           | I don't know what the currents would be, proportions or
           | dimensions of epoxy, or much else. Some more research would
           | be required. But in terms of resistive heating creating gas:
           | measure and be careful!
        
         | f_devd wrote:
         | A more modern approach of doing the same to use polymerized
         | quantum dots (I believe it emits wide spectrum white when a
         | voltage is applied), and passing that through a quantum dot
         | film to get any specific wavelength.
        
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