×

Welcome to the Slashdot Beta site -- learn more here. Use the link in the footer or click here to return to the Classic version of Slashdot.

Thank you!

Before you choose to head back to the Classic look of the site, we'd appreciate it if you share your thoughts on the Beta; your feedback is what drives our ongoing development.

Beta is different and we value you taking the time to try it out. Please take a look at the changes we've made in Beta and  learn more about it. Thanks for reading, and for making the site better!

MIT Student Gets Artistic With LED Art

Zonk posted more than 6 years ago | from the what-are-they-teaching-those-kids-up-there dept.

Education 163

Gibbs-Duhem writes "An MIT graduate student has up a page showcasing a standout art project. He's designed custom LED light fixtures which are seven times brighter than the closest similar commercial models, and include colors which can't be reproduced by a normal RGB cluster (including two ridiculously bright UV LEDs). The result: some beautiful mixed media artwork. The author's goal is to eventually publish a guide to make getting into creating such artwork more accessible to the general public. The site includes lots of great photos and a movie of the art in action. It also has in depth descriptions of the theory involved in this relatively new form of art, an explanation of how the paints were chosen, and an in depth technical discussion of how such lights are designed with schematics and board layouts for those who might wish to build their own lights."

cancel ×
This is a preview of your comment

No Comment Title Entered

Anonymous Coward 1 minute ago

No Comment Entered

163 comments

LED art (5, Funny)

saskboy (600063) | more than 6 years ago | (#22770554)

I've thought for a while that there are great possibilities for LED art. One project I'm not ambitious enough to set out to complete, would be a country's flag, arranged like lite-brites into the recognizable pattern and colours. The whole thing would be powered by a tiny windmill, making it a wind powered flag.

Re:LED art (1)

xaxa (988988) | more than 6 years ago | (#22772146)

There's some real CFL art [dezeen.com] that's much more impressive than this LED art. (For those who don't want to click, it's CFLs, but the tubes aren't compact, but big and swirly and pretty. I'll go back to my psychoactive drugs now, thanks :-)

damnit (4, Funny)

MOMOCROME (207697) | more than 6 years ago | (#22770566)

I misread it as "MIT Student Gets Arrested With LED Art" which is of course very exciting as it suggests LED Art is now illegal in Mass.

It's strange to feel all deflated by reading about a cool and hackish thing like that.

Re:damnit (2, Informative)

Anonymous Coward | more than 6 years ago | (#22770622)

Re:damnit (0, Flamebait)

Trogre (513942) | more than 6 years ago | (#22771426)

I thought someone might bring up the Boston talking milkshake party. Those silly sods deserved all the police attention they received.

Re:damnit (0)

Anonymous Coward | more than 6 years ago | (#22771496)

I thought someone might bring up the Boston talking milkshake party. Those silly sods deserved all the police attention they received.
Get the FUCK out of my country you fucking totalitarian boot licker.
Go cower in fear somewhere else, you don't belong here because you are neither free nor brave.

Re:damnit (0)

Anonymous Coward | more than 6 years ago | (#22771702)

+10000 Get out, GP. You're not needed here.

Re:damnit (1)

Aerion (705544) | more than 6 years ago | (#22770640)

I misread it as "MIT Student Gets Arrested With LED Art" which is of course very exciting as it suggests LED Art is now illegal in Mass.


No, that really did happen. Seriously. [boston.com]

Re:damnit (1)

fastest fascist (1086001) | more than 6 years ago | (#22771484)

...Although, if the reporting is accurate and she did indeed try to walk through a security checkpoint, wearing a bundle of wires and circuitry on her chest without responding to security personnel when they asked what the thing on her shirt was, the blame for that incident lies squarely on the MIT student's shoulders.

Re:damnit (5, Insightful)

Anonymous Coward | more than 6 years ago | (#22771552)

Although, if the reporting is accurate and she did indeed try to walk through a security checkpoint, wearing a bundle of wires and circuitry on her chest without responding to security personnel when they asked what the thing on her shirt was, the blame for that incident lies squarely on the MIT student's shoulders.
While the reporting was heinously distortive, it was never quite as wrong as you got it.

Not even faux news said she tried to walk through a "security checkpoint" - all she did was ask a question of the person at the info desk.

The person at the info desk - NOT EVEN VAGUELY SECURITY PERSONNEL - asked her what the LEDS were, she said "art" and then continued about her business.

The blame lies solely on stupid CYA security policies that require a "response no matter what" -- that's escalation without application of rational thinking. You've got one dumb cluck of a info-desk clerk, who probably doesn't even have a high school diploma, causing a major incident that could have been easily avoided if anyone at any step of the way had applied a degree of critical thought to the issue. What's next? Exvacutation because someone dreams about a bomb? [guardian.co.uk]

Don't think for a minute that any of this anti-terrorism "security" is about protecting anyone from actual threats. They might as well name them the Department of the CYA because their sole purpose is to protect the asses of the people in charge. If they react completely out of proportion to any perceived threat, then when an actual threat slips through they can point at all of their over-the-top reactions in the past as proof of 'diligence' thus insuring their asses are well covered, and may even get increased funding...

This institutionalized cowardice is destroying our country, it has got to stop or we will never be able to maintain our status as the largest superpower.

heinously distortive (1)

Tetsujin (103070) | more than 6 years ago | (#22773374)

the reporting was heinously distortive


I feel this bit bears repeating. In both the "Mooninite scare" and the Star thing, one very disturbing aspect of all the local reporting was that it was very heavily spun in favor of the city, the TSA, etc. Referring to a pack of D cells and some LEDs as a "Hoax Device" - even when it was already damned obvious that the Mooninites were neither bombs nor hoax bombs - is just a cheap tactic to make people side with the authorities, despite little matters like common sense getting in the way.

Re:damnit (1)

Frank T. Lofaro Jr. (142215) | more than 6 years ago | (#22774346)

What happened to her (Star Simpson)?

No news of conviction, sentence or acquittal or much of anything?

Did she "disappear"?

As controversial as her actions were (*), the fact that there is not even a wikipedia article on her is shocking...

(*) People saying everything from she should've been shot, should go to jail for the full 5 years all the way towards making her out to be totally innocent of anything, including being a bonehead.

Re:damnit (0)

Anonymous Coward | more than 6 years ago | (#22774552)

What happened to her (Star Simpson)?
She opted for a bench trial and after a handful of delays by the state is due for a ruling in the next week or so.

I suspect her wikipedia article was a victim of the ongoing purges. She certainly had one within hours of the original news breaking.

I have found it incredibly difficult to track news of her progress myself, in part because there is so much noise - hundreds of web pages from the first few days that all tend to aggregate at the top of the search results from google and the other engines. Plus the fact that O.J. Simpson is a "star" doesn't make it easy either.

Re:damnit (1)

flajann (658201) | more than 6 years ago | (#22771808)

Oh you mean: Star Simpson's Big Wrong [urlbit.us]?


Not that LED Art (and advertisements, if you recall the other idiot overreaction to the LED ads in Boston) is "illegal", but...

Any sufficiently advanced technology is indistinguishable from a BOMB to Mass Holes!


Well, now I've said it.

It's a nice project, but... (4, Funny)

megaditto (982598) | more than 6 years ago | (#22770576)

It's a real shame they don't make LEDs that emit UV-C. Those would be much better at burning retinas and giving people skin cancer.

Re:It's a nice project, but... (0)

Anonymous Coward | more than 6 years ago | (#22770786)

Do not look at LED with your remaining..., never mind.

Re:It's a nice project, but... (1, Informative)

Anonymous Coward | more than 6 years ago | (#22773226)

The problem with making UVC LEDs, as opposed to other wavelengths, is that the LED is damaged by the 100-280nm light it emits. There are UVB (280-315nm) light emitting diodes, so making them is an immediate technological hurdle. Then after that people will be complaining about there not being any soft x-ray LEDs.

On the bright side, UVC lasers already exist.

Analogies to audio (0)

Anonymous Coward | more than 6 years ago | (#22770580)

The analogies to audio perception are pretty questionable.

Don't forget to wear sunglasses. (5, Informative)

cjdavis (13840) | more than 6 years ago | (#22770590)

Doesn't UV cause cataracts?

Ah yes, from the article:

As a word of warning, the NCSU034A LEDs output over 300mW of UV light at 385nm! This is a LOT! What makes them especially dangerous is that the die is only a millimeter or two on a side, so the angular intensity of the light is extremely high. Do *NOT* turn these on in an environment where anyone can look directly at them. They are extremely dangerous to the eye, and you will have a *permanent* blind spot if you look directly at them. To make them safe, I used polyethylene plastic sandwiching a Luminit Holographic Light Shaping Diffuser (LSD... yeah, I know, they came up with the acronym first) an inch and a half away from the board to make the apparent source size over an inch in diameter. This decreases the angular intensity from the class 3b level to the class 1 level. I am not liable if you blind yourself by using these LEDs! Seriously, don't fuck around with these.

Funny story that. Every time I tell an MIT student that the UV LEDs will permanently blind them if they remove the cover, the response is the same. First, they say "Really?", and then they attempt to look into the endcap. True story. Explains a lot, I think.

Re:Don't forget to wear sunglasses. (0, Redundant)

Gideon Fubar (833343) | more than 6 years ago | (#22770620)

Goddamn it.. you beat me to it!

pardon me while i prepare for my (-1) Redundant..

Re:Don't forget to wear sunglasses. (1)

cjdavis (13840) | more than 6 years ago | (#22770636)

Well, it appears megaditto beat me, but that's only because I was off looking for references, I swear.

Re:Don't forget to wear sunglasses. (5, Interesting)

ardle (523599) | more than 6 years ago | (#22770660)

I got quite bad eye-burn from a UV spotlight (was standing about 2 metres from it for about 2 hours): not a nice experience.
Didn't notice any effect until about the following evening (thought something was in my eye). I woke in the middle of that night with stabbing pains in my eyes. Next day, daylight hurt my eyes. I couldn't even look at the flame of a candle. Thankfully, eye ointment soothed it and the problem eased the next day (disappeared over the next two or three).
Doctor couldn't figure out what had happned to me - I only figured it out (after the visit) cos the weather was cold and relief of cold breeze on my face made me realise I had got sunburnt!

Re:Don't forget to wear sunglasses. (1)

Man Eating Duck (534479) | more than 6 years ago | (#22771548)

Yes, this is well known to anyone who've been skiing cross-country at the time of year when the sun gets stronger, especially if you are on large expanses of snow. Your retinas got sunburnt.
In my language we call it "being sun-blinded". The symptoms are exactly as you describe them.
I'm surprised that your physician didn't recognise them for what they were. On the other hand, there is no cure except for ointments that give relief, so he got that part right :)

Re:Don't forget to wear sunglasses. (3, Insightful)

dattaway (3088) | more than 6 years ago | (#22770692)

I brought a homemade 250mW laser to work one day. I warned everyone exactly what it could do. What is the FIRST thing each guy did? Try to aim it in each other's faces. True. Lights are like toys and turns people into kids. Get ready to grab it out of their hands.

Re:Don't forget to wear sunglasses. (2, Funny)

Anonymous Coward | more than 6 years ago | (#22770906)

I watched the video from the site and now I have three dead pixels in my left eye. Thanks a lot, Brian!

You succeeded where Goatse failed.

Re:Don't forget to wear sunglasses. (1)

ArchieBunker (132337) | more than 6 years ago | (#22771794)

Maybe I'm missing something here, but what is the point of using UV leds? Is it not called Ultra Violet because its above the spectrum of visible light?

Re:Don't forget to wear sunglasses. (1)

xaxa (988988) | more than 6 years ago | (#22771918)

I haven't read the article, but perhaps there are UV-reactive materials being lit up, which produces colours not normally available to the artist.

Re:Don't forget to wear sunglasses. (1)

Gibbs-Duhem (1058152) | more than 6 years ago | (#22775138)

The paintings have fluorescent paint in them. It's pretty cool looking to have bright red light at the same time that your fluorescent paints are glowing -- very wild.

Art with LED (3, Informative)

GregPK (991973) | more than 6 years ago | (#22770594)

The Mona Lisa is lit up with LED's Buckingham Palace is converting over to all LED lighting http://www.flickr.com/photos/lastboltnut/1466712839/ [flickr.com]. Many cities around the world are converting to LED lighting. It is really quite spectacular transformation of lighting in the world.

I expect to see 90 percent of lighting changed over to LED lighting by 2015...

Re:Art with LED (1)

rolfwind (528248) | more than 6 years ago | (#22770802)

CFLs for indoors (and certain inclosed fixtures outdoors) will continue to be the norm in energy efficiency. Metal Halide light outdoors (available at Lowes, but not Home Depot, last I checked) make good outdoor driveway lights and the light with much better color rendering than the old sodium light and excellent energy efficiency as well. It would be nice to get LEDS, no doubt, but the lumens output and price just ain't there yet. Hopefully these type of developments will change that.

While all the hoopla is around lighting these days, that only comprises about 10% of a houses electrical energy use these days, IIRC. So your max savings is 10% -- a good and worthy start but not enough. Many electrical devices are already operating at high efficiency (electrical motors for instance) so many appliances can't be improved. Other devices just need to be used less (washer, dishwasher) through conscientous use, and things like Computers just need to be set correctly for energy savings on the software level (or make sure things like Printers come with their own print server rather than have a computer act as one... sometimes it's good to get a router with a harddrive as well...

But all this doesn't change the fact that most houses themselves are built to use way too much energy. Until that is solved, the other problems are at least orders of a magnitude smaller:
http://en.wikipedia.org/wiki/Passive_house [wikipedia.org]

Re:Art with LED (1)

GregPK (991973) | more than 6 years ago | (#22770848)

http://www.leonardo-energy.org/drupal/node/809 [leonardo-energy.org]

Article mentions this PDF http://www.netl.doe.gov/ssl/workshop/Report%20led%20November%202002a_1.pdf [doe.gov] from the DOE that outlines LED technology Roadmap putting LEDs at the same price of CFL lighting by 2012. Currently, LED technology is already ahead of the roadmap. www.LEDSmagazine.com

Also, in commercial spaces as it stands today. LED actually pays out in the long-term(5-10 years) when you factor in the cost of replacing the bulbs every few years. Even better, there is 0 mercury content in LED. Plus, LED is getting cheaper and cheaper every year when you calculate all the costs involved. Which leads to the idea that LED will pretty much replace 90 percent of lighting by 2012.

Perfect Timing (1)

nsfw (803412) | more than 6 years ago | (#22772282)

Sweet... When all my my CFL's burn out in approx 2012, then I can replace them all with LED bulbs.

Re:Art with LED (1)

Archon-X (264195) | more than 6 years ago | (#22770826)

A lot [Like the Louvre, British Museum etc] seem to be converting to fiber optics as well. Creates a lovely fill, and also really nice overlapping umbras..

Re:Art with LED (4, Interesting)

Peeet (730301) | more than 6 years ago | (#22771030)

Well, speaking from the event production industry (lighting for theatre, film, concerts and conventions) I don't see it coming that quickly. There are ways for LEDs to take over this industry, but they all depend on some other technology or innovation happening first. LED based fixtures are starting to be used as a tool, but they are in their own category, not as a replacement for an already existing tool. The problems that LEDs have are their color rendering index, their lack of brightness and the inability to dim them via the equipment currently used in almost every theater and production company in the industry (dimmers, PARs and Ellipsoidals). Color rendering is being addressed in the same manner as this MIT student (Selador's x7 series [selador.net] uses 7 different color LEDs to expand their palette) and brightness is fast becoming a non-issue as 3 watt LEDs are becoming commonplace. But dimming is the deal breaker as the industry is saturated with SCR based dimmers that control a majority of the conventional lighting fixtures by way of dimming their main AC input.

For LEDs to be viable, they would have to be able to replace the HPL lamp that is used by the defacto industry standard lighting fixtures: ETC's Source Four [etcconnect.com] PARs and Ellipsoidals. These "conventional" lights plug into distribution cabling that goes directly back to a dimmer rack of some sort where the AC voltage is varied by way of using an SCR to chop the AC waveform at various points thus varying the voltage output and dimming the incandescent lamp. LEDs use DC power and are dimmed by flashing them on and off very quickly (at a constant voltage) and varying the amount of time that they are on versus off to create the illusion of dimming. If you were to put an LED controller onto a dimmed AC circuit, it would fry the controller much the same way that an electric motor would get fried if it were on a dimmed circuit. Sine Wave dimming (new technology) may change this, but that needs to happen first and LEDs second.

There other ins for LEDs to take over this industry. The other half of the lighting industry (seen more in concerts and conventions and less in theatre and film) is moving lights [wikipedia.org]. They mostly use arc based light sources and are dimmed by way of a motorized shutter blocking the light coming out of the fixture. The power input for these types of fixtures is then run separately straight from the power source and not from a dimmer (just like current LED fixtures). They are very bright and have a slightly colder color temperature and lower color rendering index (also similar to LED fixtures). LEDs would be a perfect fit for moving lights and it is only a matter of time before we see new fixtures being developed with clusters of LEDs powering them rather than an arc lamp. The only problem with this is that it is hard to make optics that will still focus sharp with a source that has multiple points of origination.

The final point I will make addresses this problem, I believe. Once you start seeing high powered video projectors running off of LEDs rather than arc lamps (as most are now) then there will be no excuse for LEDs not to take hold of the lighting industry as we are also experiencing another revolution where traditional moving lights whose beams are shaped and colored by metal patterns and glass color filters that are mechanically placed in front of the beam inside the fixture are being replaced by essentially video projectors on moving yokes that project all of the colors and patterns by way of a computer video output. Once video projectors have been taken over by LEDs, THEN I predict, at least in this industry, we will start to see some tool replacement rather than just toolbox supplement.

Re:Art with LED (1)

GregPK (991973) | more than 6 years ago | (#22771336)

CRI is pretty much a non-issue already. See Mona Lisa... They use a mix of LED colors to get whatever color they want. They can actually get a higher color rendering index than incandescent with LED lighting. Without the Fading, and Infrared that standard lighting setups put out.

As for the dimming effect I think you could possibly put an LCD over the LED and dim it out with that connected to a controller to output whatever pattern or color you want.

I don't really see production lighting as all that expensive to operate as far as power goes. So using LED on a cost basis isn't really going to pay out there until you see daily usage of 12 to 6 hours a day.

Incandescent bulbs will still have some commonplaces settings perhaps stage lighting is one of them...

Re:Art with LED (1)

xaxa (988988) | more than 6 years ago | (#22772072)

I dunno... for the Lord of the Rings play at a theatre in the West End, London (UK) they had to put generators outside the back of the building to provide extra power for the lighting effects required -- the normal (for a theatre) power wasn't sufficient! Since a house here gets a maximum of 11-22kW (50-100A×230V) and I expect a theatre gets a fair chunk more than that, that's a decent expense. Worth reducing, anyway.

P.S. sometimes I go to a nightclub at a weekend and stay for longer than I was at work on Friday. 22:00 until 07:30 the next day, for instance. Of course, the lighting saves heating costs!

Re:Art with LED (1)

xaxa (988988) | more than 6 years ago | (#22772030)

Moving lights are used loads in concerts and nightclubs in London (UK). About the only place I can think of that doesn't have any has a really low ceiling (as in, "don't jump!" low). I don't pay much attention, but places like the couple of student union clubs I go to have almost entirely this lighting, with larger venues having maybe half their lights of the standard type.

I've seen LED lights used a little at at small venues and at really large concerts, but not at anything in between. I was told that a particularly awesome one cost £6000, which was why the student union was merely renting some for the night (the last day of term). I wasn't impressed with the ones used at some smaller venues -- they were set to flash and it was distracting, since there was no fading (presumably on the cheap light used). At large concerts they tend to be there for colour and show, and proportionally don't provide much background light, so flashing isn't a problem.

They're loved at non-mainstream clubs where a lot of people are probably on E, where the intensity and the way they can flash is really appreciated :-). So are lasers, they must have become a lot cheaper since I've seen a few recently.

Re:Art with LED (1)

vertigoCiel (1070374) | more than 6 years ago | (#22771188)

I expect to see 90 percent of lighting changed over to LED lighting by 2015...
I don't. In commercial and public settings, maybe. Not in homes, though. People are too used to the way incandescent bulbs look. A room feels very different when lit by a white LED instead of the yellowish tone of incandescents - and not in a good way.

Re:Art with LED (0)

Anonymous Coward | more than 6 years ago | (#22771246)

People are too used to the color spectrum from the sun. I'll get with Monsanto to get that fixed.

Re:Art with LED (1)

GregPK (991973) | more than 6 years ago | (#22771258)

This is already been addressed. You can order LED lighting in pretty much the same color as your standard incandescent at 2700k or 3100k. It's not going to be as efficient as a white would be. But, inside people are more comfortable with the standard yellowish colors and it makes sense.

Re:Art with LED (1)

Trogre (513942) | more than 6 years ago | (#22771300)

Six years ago people in my city struggled with the same issue when presented with new-fangled CF technology. Then power prices went up, CF technology improved and bulb prices came down.

Now everyone has them and incandescents are a novelty, not the norm.

Re:Art with LED (1)

Amouth (879122) | more than 6 years ago | (#22774160)

i use alot of incadescent lights.. but that is because almost every light i have is on a dimmer.. once they can get CPF's working right on dimmers then i will be happey to use them all the time.

Re:Art with LED (1)

Alioth (221270) | more than 6 years ago | (#22772466)

I'd be surprised. Sodium lights are still by far the most efficient light source we have - so far ahead of semiconductor lights in efficiency, it's not even funny. LEDs have a long way to go to match the brightness and efficiency of sodium street lighting.

From the article.. (1)

Gideon Fubar (833343) | more than 6 years ago | (#22770604)

Every time I tell an MIT student that the UV LEDs will permanently blind them if they remove the cover, the response is the same. First, they say "Really?", and then they attempt to look into the endcap. True story. Explains a lot, I think.

Nothing changes (1)

Kupfernigk (1190345) | more than 6 years ago | (#22771612)

This is how it is with physicists and engineers, since Galileo damaged his sight looking through his telescope.

Remember the guys on the Los Alamos project who thought it was cool to have a lump of gold plated plutonium on a stand so you could feel how warm it was? And then there was the scientist I once had the pleasure of working with who thought it was clever to have his 5kV capacitor bank with the live prongs exposed and joined by a copper rod, though the CEO did get pushed out of the way before he could touch them and kill himself. As my physics teacher used to say "Physicists have their own version of natural selection", though he was talking about some people he had worked with who couldn't be bothered to use the shielding when working with X-rays.

Art? (1)

unbug (1188963) | more than 6 years ago | (#22770624)

Whatever happened to the difference between art and design?

Re:Art? (1)

DNS-and-BIND (461968) | more than 6 years ago | (#22770676)

Oh, it's the usual - outsiders desperately trying to get the coveted label of 'artist' even though most of them will spend their careers designing circuit boards or some other banal horror. Let's just say that this student won't be getting profiled in The New Yorker anytime soon.

Fascinating (5, Interesting)

djlemma (1053860) | more than 6 years ago | (#22770646)

I haven't read the whole article, but anything having to do with LED technology is interesting to me. It's interesting, though, that the author doesn't seem to understand color mixing in pigment vs. light.

He says-
"You mix red paint and green light, you get what appears to be yellow light."

That's not true. If you mix red LIGHT and green light, you get what looks like yellow light. If you shine green light on red paint you get a ugly dark mess. The red paint doesn't reflect the green light very well- the reason it's red is because it reflects the red portion of the spectrum. So, when you light it with green, the light that's reflected off the red is not going to be very intense, it certainly won't be yellow.

Also important is the fact that green is a primary color in light, while yellow is a primary color in pigment. If you shine green light on yellow paint, you'll actually reflect a lot of green, and if you shine yellow light on green paint it'll also (you guessed it) reflect lots of green.

I think it's interesting that he's finding out how the horrible color rendition capabilities of LED's can be used to one's advantage, but I don't know if he really understands all the theory involved...

Re:Fascinating (4, Informative)

batkiwi (137781) | more than 6 years ago | (#22770850)

He gets it but just has a bit of a typo. If you read the rest of that paragraph it's obvious he meant "You mix red light and green light, you get what appears to be yellow light."

I say this because he later remarks on:
-"You may think you're seeing yellow light, but the fact is that you are seeing independent red and green light, and your brain is converting that information into the appearance of yellow"
-pointing a "yellow" LED at "yellow" paint (black!!)
-pointing an "orange" LED at "orange" paint made by mixing yellow and red paints (red!!)
etc

Don't crucify him for just one word mixed up.

Re:Fascinating (1, Informative)

djlemma (1053860) | more than 6 years ago | (#22770938)

I didn't see a picture of the yellow LED pointed at yellow paint, but I'd wager money that you would end up with yellow, not black. Yellow pigment reflects wavelengths in the red and green parts of the spectrum. You'd have to make some sort of crazy dichroic to only reflect back a specific band of yellow, and I don't think that's what this guy was talking about.

Basically, I don't think it's just a typo. I think he's got a basic understanding of color mixing, but he's trying to explain beyond what he really knows.. hence mistakes like mixing up light vs. pigment, or saying that yellow pigment looks black under yellow light.

Re:Fascinating (1)

Immerial (1093103) | more than 6 years ago | (#22771528)

Don't crucify him for just one word mixed up.

Uh, have you read comments on slashdot much? Duh. :)

Re:Fascinating (1)

rastoboy29 (807168) | more than 6 years ago | (#22770876)

Hmm, he does have pictures.  Did you look at them?

Re:Fascinating (2, Interesting)

djlemma (1053860) | more than 6 years ago | (#22770896)

Yes, I looked at the pictures, and as far as I could tell they outright contradicted some of the things he was saying. He claimed that the mixed yellow light of the LED's (a red LED with a Green LED) would make yellow pigment turn black, but if you look at the yellow illuminated image you can see that's not the case..

A lot of the stuff this fellow was saying about color mixing and perception just seemed a bit off. The electronics are cool, but I'd look elsewhere for an explanation of the optics involved.

Re:Fascinating (0)

Anonymous Coward | more than 6 years ago | (#22771206)

I think this is a slight typo on his part. If you read the following two paragraphs you'll see that he goes into an in-depth discussion of exactly the discrepancy you mention.

Re:Fascinating (0)

Anonymous Coward | more than 6 years ago | (#22771980)

I wouldn't give too much about gamut theories from someone who thinks that "the camera CCD seems to have better blue sensitivity at the borders than the center, so the color appears to be nonuniform." Obviously the color shift is plain old clipping, where the blue channel is maxed out, but the small percentage of other colors in the light can still increase with the higher light intensity at the center, so the color perceived by the sensor shifts.

Meh (4, Funny)

timeOday (582209) | more than 6 years ago | (#22770656)

What's the big deal with this "can't be reproduced by a normal RGB cluster"? All the colors in the screenshots look pretty normal to me, nothing out of the regular gamut. Just like all these suckers and their (so-called) "high-def" TVs, which I've seen in many commercials yet none showing a better picture than the fine Trinitron I already have. Nothing to see here...

Re:Meh (2, Funny)

LunarCrisis (966179) | more than 6 years ago | (#22770902)

What's the big deal with this "can't be reproduced by a normal RGB cluster"? All the colors in the screenshots look pretty normal to me, nothing out of the regular gamut.
Damn, I followed this article's link from my feed reader to make that very joke, but now that I'm here I see that you've already done a fine job of bungling it...

At a music festival in australia this year.. (1)

sleeponthemic (1253494) | more than 6 years ago | (#22770694)

There was an LED art installation. It consisted of pretty large array of rgb leds arranged into cube. The LEDs were housed in what looked like ping pong balls or something to this effect. The effects it could produce were phenomenal. The switching was obviously extremely configurable as they were able to amazing shows. Imagine seeing shapes created by these leds moving in any directions (migrating to different leds obviously), changing colours etc. Could only find this video of it. Would have been better to have taken it a bit further away. http://au.youtube.com/watch?v=FGNQDpJdl14 [youtube.com]

Re:At a music festival in australia this year.. (1)

djlemma (1053860) | more than 6 years ago | (#22770748)

See, that reads more to me as "LED Art" than what the author of the article was trying to do. Basically, the article was just explaining how to build your own version of a readily available type of luminaire. The only thing he seems to think is innovative about his is the inclusion of high-power UV LED's. Well, that's cool, and I hope ColorKinetics [colorkinetics.com] (or some other manufacturer of LED lighting) picks up on that idea if they haven't already.. but there's really nothing particularly artistic about the project. It's still cool, though.

lights for photographers? (1)

rice_burners_suck (243660) | more than 6 years ago | (#22770754)

A very, very cool project. I wonder if a similar project could produce colored lighting for artistic photography. Heh, by the scan of the schematic, it looks like he's using EAGLE [cadsoft.de] for his PCB design. EAGLE is a very good program.

Re:lights for photographers? (1)

djlemma (1053860) | more than 6 years ago | (#22770792)

For artistic photography, unless there's some major reason why you need the narrow band of light created by LED's, you're going to be better off using regular old gels to change the colors of your lights. To get enough intensity with LED's to match a studio strobe, you'd spend a small fortune. Gels cost $5 for a 21"x24" sheet, and there are literally thousands of colors to choose from, and you can use them with any photographic light source.

Re:lights for photographers? (1)

Archon-X (264195) | more than 6 years ago | (#22770834)

I use led sources to paint my scenes all the time - but I am shooting night photography, so it's a fairly specific application.

Re:lights for photographers? (1)

djlemma (1053860) | more than 6 years ago | (#22770864)

Oh, that sounds cool.. I can see how it would be advantageous to have something small with strong battery life, like an LED maglite or something.

Are any of your images viewable online? Flickr?

Re:lights for photographers? (1)

Technician (215283) | more than 6 years ago | (#22773068)

you're going to be better off using regular old gels to change the colors of your lights.

That used to be true. Many LED fixtures now provide as much light as filtered PAR lights. As a bonus, there is no IR and UV contamination. Gel's tend to be fairly wide in their response, so some artistic shots with very saturated colors can't beat LED fixtures for rich color. For example, take the original story and look at the red/green room. Conventional gel's can't produce that stunning color. Good effects can be had with off the shelf DMX 512 LED wash lights. Controllers are getting dirt cheap with many under $150 that can control a dozen multi-channel RGB fixtures.

http://www.music123.com/Chauvet-DMX-40B-DMX-512-Controller-801517-i1176897.Music123?source=ZWWRWXGB [music123.com]

Here is a 6pack of PAR RGB LED fixtures for under $100 each.
http://cgi.ebay.com/6-x-LED-RGB-Par-CANS-DMX-Oboard-1300-Lux-15m-0S-H_W0QQitemZ300207441774QQihZ020QQcategoryZ29944QQcmdZViewItem [ebay.com]

Not first MIT artwork on display (1)

dotancohen (1015143) | more than 6 years ago | (#22770756)

Didn't some MIT idiot pushed her way past aitport security with LED-lightwork and an exposed circuit board less than a year ago? I'm too lazy to google it (I'm can't be bothered to fact check when posting to /.), but the incident stands out in memory.

Re:Not first MIT artwork on display (1, Funny)

Anonymous Coward | more than 6 years ago | (#22770796)

Didn't some MIT idiot pushed her way past aitport security with LED-lightwork and an exposed circuit board less than a year ago?
No.

I'm too lazy to google it (I'm can't be bothered to fact check when posting to /.),
Clearly.

but the incident stands out in memory.
Perhaps, if the rest your brain was sufficiently camouflaged.

Re:Not first MIT artwork on display (0)

Anonymous Coward | more than 6 years ago | (#22770804)

I believe it was a proto-board with LEDs in the shape of her name (Star) and a battery to power them, and that she was merely waiting outside the security station for her boyfriend's plane to arrive when she was arrested at gunpoint.

But it's OK if you could't be bothered to check the facts :)

Places to buy indoor LED lighting? (1)

Dogun (7502) | more than 6 years ago | (#22770760)

The pic with the 2-tone room (red half, green half) makes me want to convert mine. Anyone know where people can buy colored LED lighting for @home, indoor application? I've not had a lot of success searching in the past.

oh oh (0)

Anonymous Coward | more than 6 years ago | (#22770776)

Call the bomb squad.

Cool but PCB design work could use some help (0)

Anonymous Coward | more than 6 years ago | (#22770812)

I wouldn't use his PCB designs. Goodness, there are 90 degree trace turns everywhere and no copper fills. Makes me dizzy looking at it. Oh well.

Re:Cool but PCB design work could use some help (1)

Alex Belits (437) | more than 6 years ago | (#22770840)

The PCBs are pretty horrible, but not for those reasons.

Pads for through-hole IC and connectors have multiple places where a trace leaves the pad at a wrong angle, continues toward the nearest pad on the same connector, then turns away from it into direction where it was supposed to go in the first place. In addition to looking sloppy, this increases the probability of solder bridges and overheating, especially if the board is assembled manually or repaired. Many traces going to those pads look so sloppily drawn, I have no idea how to achieve such an effect with any modern PCB design software (and my idea of "modern" starts at http://pcb.sourceforge.net/ [sourceforge.net] ).

Re:Cool but PCB design work could use some help (1)

Alioth (221270) | more than 6 years ago | (#22772572)

I think that PCB is better than Eagle, the truth be known. It's likely he just autorouted the tracks as well. The Eagle autorouter doesn't have a good reputation.

It looks like his boards have solder mask on them, so the chances for briges are probably pretty low.

In all probability, it may be one of the first PCBs he's done. My first PCBs looked pretty bad too. They were also hand etched, which soon teaches you about copper fills and routing traces for easy solderability.

Re:Cool but PCB design work could use some help (1)

TheBig1 (966884) | more than 6 years ago | (#22773514)

Slightly off topic, but I just found KiCad [sourceforge.net] which I find miles ahead of either PCB or Eagle. The learning curve is a little steep (and the software was originally French, translated to English), but if you take a half hour and follow through a tutorial (I used http://www.kicadlib.org/Fichiers/KiCad_Tutorial.pdf [kicadlib.org] which worked well for me), you can see how simple it really is.

I am in no way related to this project, but am just a very satisfied user.

Re:Cool but PCB design work could use some help (0)

Anonymous Coward | more than 6 years ago | (#22771492)

"...90 degree trace turns..."

OMG!

Really, 90 degree trace turns?

Everyone knows that electrons can't turn sharp corners.

Those scientistic guyz sure don't know nothin', do they?

Worst. Explanation. Evar. (3, Insightful)

Alex Belits (437) | more than 6 years ago | (#22770816)

Theory

The first step of the project was to understand the underlying physics behind LED based artwork. Fundamentally, the eyes are a very odd sensing system. The ears do a frequency based analysis of incoming pressure waves, and report all of the dominant frequencies to the brain for interpretation --- if we hear two frequencies of different pitches, they sound distinct. This isn't quite as true when you talk about harmonics of sounds, as they will start to affect the timbre instead of sounding as a distinct pitch, but the basic idea is that we can pick out independent sounds with different pitches fairly easily.

The eyes, on the other hand, do spatial and frequency-based sensing; however, they throw away much of the information about the specific frequencies detected. For instance, if you look at any particular spot, you will see a single color -- not a spectral map of the complete visible spectrum coming from that point. This is great for the purposes of vision; it would be rather difficult, I think, to walk around while receiving that much information. However, this means that the eye behaves very strangely in the presence of multiple colors from the same location.

The classical example of this effect is the color wheel. You mix red paint and green light, you get what appears to be yellow light. But how is this possible? If yellow is a frequency of light, how does mixing red (620nm) and green (530nm) produce yellow (590nm) light? There is certainly no physical process that does this sort of mixing in general.

In fact, the idea that red and green combine to form yellow is a trick of the mind only. You may think you're seeing yellow light, but the fact is that you are seeing independent red and green light, and your brain is converting that information into the appearance of yellow! Very strange. So, this can explain how a RGB cluster of LEDs can produce most colors of light -- they aren't actually producing those other frequencies of light; instead they are tricking the eyes into thinking that they are producing those other frequencies of light. This trick is summed up in the Chromaticity Diagram (pulled from wikipedia). On this diagram, pure frequencies are displayed along the outer border from 460 to 700nm. As you mix two colors together, you draw a line between their positions on the border, and the ratio of the two tells you the position in the diagram that your apparent color lies. For example, if you combine 520nm green light with 620nm red light in a 50-50 ratio, you will have what appears to be yellow light. Likewise, if you have 620nm red light and 490nm cyan light in a 50-50 ratio, you will have what appears to be approximately white light.
I have never seen a worse explanation of color vision.

It would be sufficient to say this:

Human eyes' colored light sensors cover wide ranges of wavelengths with maximums at red, white and blue, so they can easily see colors of mixed paints (also wide ranges of wavelengths with multiple maximums) and have those colors imitated by LED screens and lights (three very NARROW ranges of frequencies near the maximums of eye sensors' sensitivity) however mixing the two (light from three narrow-band sources is reflected by wide-band paint, then seen by three types of wide-band sensors) produces distorted results because paint's reflectivity of wavelengths outside the lights' narrow bands does not contribute to the impression.

A paint with one of the narrow maximums at, say, cyan, will appear the same as paint without such a maximum if illuminated by a LED light that produces nothing in cyan range where the maximum is present. It's important to mention that in a photo taken under natural light and displayed on a LED screen, paints' colors will appear perfectly normal. This happens because light and camera's sensors cover approximately the same ranges as human eyes' sensors, so for the area covered with paint that has cyan maximum, screen would produce more green and blue light to imitate the impression on eye's green and blue sensors.

His solution is to:

1. Add more narrow-band sources so they cover more of the spectrum.

2. Use paint that mostly reflects the same colors as light sources produce, so it does not produce drastically different results under natural/incandescent/fluorescent and LED light.

3. Use ultraviolet LEDs and fluorescent paints to produce light on wavelengths that do not appear in the ranges produced by the light sources.

What is perfectly reasonable as long as the painter sees painting and lighting as two parts of the artwork, as opposed to usually accepted model of painting with the assumption that painting will be viewed under natural or incandescent light. But $deity, the explanation was beyond horrible.

Re:Worst. Explanation. Evar. (0)

Anonymous Coward | more than 6 years ago | (#22772092)

[blockquote]But $deity, the explanation was beyond horrible.
[/blockquote]

Re:Worst. Explanation. Evar. (0)

Anonymous Coward | more than 6 years ago | (#22772204)

But $deity, the explanation was beyond horrible.
Yours was much, much worse.

What the heck is the wavelength of white light?

Also, your "camera sensors" bit is broken and obscures some interesting stuff. Did you know you can take infrared photos with some digital cameras?

And *please* borrow some periods from your subject line for use in your main text.

Their clean web page needs no apology (4, Insightful)

Morgaine (4316) | more than 6 years ago | (#22770994)

From TFA: Apologies in advance for this being a simple html website. I'm a scientist/engineer, not a graphic designer.

No apologies needed. I wish all web pages were as clean as yours, instead of covered in irrelevant decor, side panels and advertising that just obscures the message and makes loading times 10 times as long as they should be.

Google's minimalist search page stands almost alone in retaining functional sanity among major websites. Don't feel bad emulating that frugality.

Horrible PCBs (0)

Anonymous Coward | more than 6 years ago | (#22771220)

Seriously dude - read the application notes for the DCDC converters with special reference to circulating currents and proximity of inductors to the switch!

Colors RGB can't reproduce... (0)

Anonymous Coward | more than 6 years ago | (#22771746)

That's great and all, but can this create Octarine light?

Superpowerful LEDs??? (1)

monopole (44023) | more than 6 years ago | (#22772162)

Luxeon Rebels and Vs? Yawn! I've been running those under PWM for over 2 years. Presently I'm rigging an RGB LEDEngin [ledengin.com] 15W Light Engine w/ 1.5 A buck boosts running through a fiber bundle conduit to drive a DLP. Had to go out and get some arctic silver epoxy and P3 heatsinks to handle the heat.
Maybe the current state of LED tech will make it to MIT in a couple of years.

Re:Superpowerful LEDs??? (1)

karnal (22275) | more than 6 years ago | (#22774830)

That's actually something I'd like to see - I'm assuming by DLP you mean projector?

Learned something new (1)

Miamicanes (730264) | more than 6 years ago | (#22772392)

I wish I had mod points today for 'informative', because the article points out something that's not intuitively obvious and explains an observation I've made for the past 2-3 years (the time since RGB LED theater lights started to become commonplace) -- why things illuminated by the "white" light from a RGB triad tend to look like crap. Specifically, the observation that if you shine "yellow" light produced by red and green LEDs onto a surface that's painted/colored yellow, the surface looks almost black, and if you shine "orange" light produced by red and green LEDs onto an orange surface, it appears to be bright red.

In retrospect, it makes sense, and I feel like kicking myself because I should have figured it out a long time ago from what I know about light bulbs and color-rendering index (CRI). The reason halogen lightbulbs have a high CRI (~98 or ~99 when running at full power, I believe, compared to midday cloudless summer sunlight's CRI of 100) is because they produce light comprised of a nearly infinite number of discrete wavelengths (or at least enough to look like it to the eyes). Likewise, the reason why colors look a little "off" under most CFL bulbs (though often better than incandescent bulbs running at reduced power) is because their CRI tends to be in the low 90s. They produce light that's the sum of a small (few dozen?) number of different wavelengths. If you look at it on a spectrometer, you see a bunch of little spikes with nothing in between. Old/cheap fluorescent bulbs look even worse, because they used fewer different phosphors and had bigger gaps between spikes.

This is relevant, because it makes it obvious why attempts to light a stage using ONLY theater lights comprised of red, green, and blue LEDs will produce less than spectacular (if not downright odd) results -- effectively, a light that produces "white" light from red, green, and blue LEDs is like a poor-quality low-CRI fluorescent light from the distant past... but worse. It's not a question of "temperature" (bluish, yellowish, etc), because your eyes can compensate for THAT (it only becomes a big deal with you're dealing with film, or putting natural and artificial light side by side where they can be visually compared). Ergo, if you wanted to make stage lamps capable of reproducing halfway natural-looking color, you'd need to combine -- at the BARE minimum -- not just red, blue, and green LEDs... but also yellow, and augment it with high-CRI halogen lights. Cyan, magenta, and orange LEDs probably wouldn't hurt, either. You'd use the halogen lights for general illumination, and use the LED lights to tip the color balance for effect (being aware that the more you dim the halogen and brighter you make the LEDs, the more the color quality of the light is going to deteriorate).

PWM dimming of RGB LED's is patented (2, Insightful)

marcop (205587) | more than 6 years ago | (#22773320)

Color Kinetics (now owned by Philips) has a patent entitled "Multicolored LED lighting method and apparatus" (6,016,038). It's such a trivial invention which should have prior art. Yet they used it against Super Vision International and it was upheld in court.

I hope this student got a license.

Re:PWM dimming of RGB LED's is patented (1)

virtualXTC (609488) | more than 6 years ago | (#22774470)

Actually, IIRC much of the foundation of Color Kinetics, as well as Brian's work, was done by another MIT student, frostbyte [mit.edu] (now deceased), and much of it probably qualifies public domain or prior art. Therefore it's likely, Phillips only has a patent on the implementation of a specific controller.

His Academic Work is even cooler! (1)

virtualXTC (609488) | more than 6 years ago | (#22773984)

I'm surprised to see Brian made the front of slashdot for his artwork when his academic work, converting ethanol to H2 by creating Rh and CeO2 nanowires using a genetically engineered T9 capsid as the wire template seems far cooler. Unfortunately, is lab's home page [mit.edu] seems to be down at the moment.

Patent violation! (0)

Anonymous Coward | more than 6 years ago | (#22774414)

One of the reasons commercial LED color mixing units are so expensive in the US is patents. Color Kinetics (now owned by Philips) have a large set of patents covering color mixing with LED's using PWM which this project appears to be doing. Most US manufacturers have been forced to license this from Color Kinetics. Attempts to overturn the patent have failed e.g. http://www.ledsmagazine.com/news/3/12/3 [ledsmagazine.com]

Don't try using Pulse Amplitude Modulation for color mixing either - that's also been patented!

Anti-mold UV? (1)

mi (197448) | more than 6 years ago | (#22774686)

Could this ultra-violet LEDs be used to kill the mold and bacteria in the bathroom and kitchen, while nobody is there?

Or are the rays too weak?

Load More Comments
Slashdot Account

Need an Account?

Forgot your password?

Don't worry, we never post anything without your permission.

Submission Text Formatting Tips

We support a small subset of HTML, namely these tags:

  • b
  • i
  • p
  • br
  • a
  • ol
  • ul
  • li
  • dl
  • dt
  • dd
  • em
  • strong
  • tt
  • blockquote
  • div
  • quote
  • ecode

"ecode" can be used for code snippets, for example:

<ecode>    while(1) { do_something(); } </ecode>
Sign up for Slashdot Newsletters
Create a Slashdot Account

Loading...