Soda bottles become electricity-less "light bulbs" for the poor

In many of the world's poor neighborhoods, homes are built out of whatever materials people can get their hands on, often without windows or electricity. That means the buildings are awfully dark during the day, reducing quality of life, safety, and productivity.

But the situation can be improved with only a used soda bottle, some water, and some bleach. Check out this clever solution, developed by MIT and distributed by the Liter of Light project.

Via Grist

Video Link


  1. When I first read the story, I expected something like a simple chemical reaction that produced light (though I doubted bleach and water could do this…)

    It’s a simple, yet brilliant idea, and I’m actually surprised at its effectiveness in refracting the light in all directions.

    1. I guess there’s more soda bottles in Manila than nautical antique shops…

      Shame though, deck prisms are beautiful beautiful objects. My dad had one on his curio shelf when I was growing up and I’ve always loved them.

    1. It looked like they were applying some sort of tar or resin to the bottle tops near the end of the story. They’d probably use the same stuff to seal up the roof and prevent leaks.

    2. Those roofs aren’t very good in monsoon season either. The little bit of sealant used on the bottles and the bit of corrugated metal is probably better than whatever else (if anything at all) is used on joints and overlaps.

  2. Wow, a hole in the roof lets in sunlight, amazing. Up next on Boing Boing: Soda bottles become plumbing-less “urinals” for the poor.

      1. Well, he’s got a point. Why don’t they just hold the unlock buttons of their iPods if they need light so badly? I mean, God. /scoff

        1. iPod shmipod. Everyone knows the iPad gives off way more light. But dheisel can’t help it if brown people don’t how to use their Apple products properly :(

  3. Also, what about the fact that bottle will degrade under sunlight? When the time comes it’s gonna be quite a mess everywhere.

    1. How long would such degradation take? I image you just have to keep an eye on the bottle and change it every now and then.

      1. They have to be replaced about every two years, if they’re made properly. It’s important to use purified water, or the time will be much shorter.

        The story was very misleading, I thought. What this really is, is a low-tech version of the solar-tube skylight. It is in no way a “light bulb” in the way everyone understands the term, nor does it put out “55 watts”. “Lumens” is the measurement they were groping for.

  4. holy naysayers batman!

    This makes a TREMENDOUS difference in many peoples’ lives for excellent value. Even in places with electricity, this saves energy by not having to power bulbs (maybe not cf) in the daytime. If you watch the video, you’ll know that they are filled with bleach to eliminate algae and it looks like they seal the lid with expoxy and do something to seal the modification. You’ll also know that they’re intended to last for 5 years, not that they would be difficult to replace.

    1. *pedantic* Hi #15, this is Re-using, not Recycling, which involves breaking down items and turning them into something else. */pedantic*

      Reduce, Re-use, Recycle has that sequence for a reason, it’s the order of ‘holiness’. It is best to reduce your use of a resource, then to Re-use the thing for something else (wash the dishes with some water, then use that water to flush your toilet), then to Recycle it (have it re-processed), and throwing it into a away and covering it with dirt isn’t even mentioned, for obvious reasons.

      This concept is superior to a Deck Light in that it doesn’t require any precision manufacturing process, other than the one originally used to mass-produce create the bottle, and it looks much more fault-tolerant. If it gets dirty up there on the roof, you can polish it. If you don’t want the light (a shift-worker wants to sleep during the day perhaps) you can cover it with a bit of cloth.

      It’s much better than a skylight, as these don’t usually refract light much, they simply let it into the room, thus resulting in the directed light problem mentioned in the video.

      In terms of a simple solution to the problem of daylight illumination in a very poor area, this is an incredibly useful idea. The resources are widely available, it doesn’t take much training to become skilled, people can maintain it themselves, etc.

      I’m seriously considering getting some of those solatubes installed if I ever end up owning my own house, looks like a great way to cut down on daytime illumination costs for interior areas, and as it’s mostly-direct sunlight, it’s going to be healthier than electric light.

  5. If they used glass bottles, the degradation of plastic wouldn’t be an issue, and when the water finally turns cloudy/grows algae, they can just clean and refill them.

      1. In Manila? Manila Beer comes in clear glass bottles, although most of the urban poor won’t ever come in contact with Manila Beer, only the insanely cheap Red Horse in dark glass bottles. VitaMilk soy milk also comes in nice clear glass bottles. We’re using them to make a chandelier.

  6. This tech isn’t from MIT in any way shape or form. This has been utilized in the favela’s in Brazil and a number of other South American countries. This tech has been around for almost a decade. An engineer Alfredo Moser in Brazil invented this technology during a severe power outage in 2002. I find it slightly distressing that neither Boing Boing or MIT are crediting the initial inventor of this incredibly innovative low-tech lighting. Here is a link to a 2008 video on Youtube.

    I credit MIT for capitalizing on this mans unlicensed tech. but distressing that a prestigious university would not correct this oversight with information about this tech readily available on the internet since 2004.

    If I am mistaken and this was a shelved technology by MIT, my apologies but from my remedial research abilities I did not find this tech on MIT’s website easily, or credited before the 2002 invention by the gentleman in Brazil.

    Boing Boing, I respect and enjoy your coverage of alternative tech and low tech solutions to problems, but after seeing a number of mis-credited techs I have finally commented. I work in the alternative materials field, and find that first world schools and inventors continue to capitalize on work done far afield of their labs and campuses. necessity is the mother of invention, and necessity in the low tech field such as this is an unrecognized or unacknowledged need in developed nations. these kinds of techs are majority creations by those who desperately need the solutions they provide.

    I do not wish to detract from MIT or Boing Boing. Both are excellent in their respective fields and I appreciate all the contributions they continue to make.


  7. Deck prisms are still made and sold. Originally they served two purposes: to let light into the belowdecks spaces, and also to allow those on watch to see if fire had started at night. Now they’re useful on small boats where electric power is at a premium and has more important uses – like navigation lights and communication.

  8. dheisel – The purpose here isn’t the hole, it’s the refraction of the light from the bottle that hangs below the hole. Bending the rays makes all the difference when you’re talking about light levels being brought in from outside, just ask all those people who use Solatubes rather than traditional skylights. ( In that case, a 7″ diameter hole with a reflective interior and a well-designed lens to bounce light can brighten an entire room!

    TK – The Mythbusters already did ask about lighting up the dark using mirrors (like the scene in Legend), and realized that without something to scatter the light rays (in their case, Jamie’s classic white shirt causing diffraction), light from the sun was too well-aimed to light a dark space from a small, directed source. In the case of the liter bottles, the water and shape of the bottles causes refraction to occur, bouncing light around the room. Since the point of the exercise is partially to keep costs down, sizing containers specifically for this purpose is really out of the villagers’ reach. That’s what you do if you wanted to “Mythsize” the idea.

    It looks like the installations were being handled carefully, and sealant was applied to leaky areas, so here’s hoping it will stay bright and dry for the people using this tech.

  9. dumb question: i want to share this on facebook, and my facebook friends tend to read links with pictures a lot more than links without. why do my boingboing articles often show up without the graphic when i share them on facebook? it makes them less shared.

  10. InquiringlyMinded:

    The Liter of Light project openly credits both Alfredo Moser and the use of glass bottles for similar purposes that predates his work. They credit an MIT team with their particular design, which does differ slightly from Moser’s (he sealed his bottles with empty film canisters, which I’m guessing are less common these days).

    I can’t find any evidence that MIT is “capitalizing on this man’s unlicensed tech”–to begin with, they’re not profiting off the technology, and the idea predates Moser’s work, albeit with glass. Most importantly, I’m not seeing MIT getting (or taking) full credit anywhere except in this Reuters clip, and on sites featuring the Reuters clip with little other information.

    I think the problem here isn’t appropriation of technology so much as shoddy journalism.

  11. Stupid STUPID idea…… poor people has many holes in the roof in the rainy…. rainy season in Philippines…
    “I image you just have to keep an eye on the bottle and change it every now and then.”
    “They do make translucent corregated plastic.” give for free to the poor people…. this is better!!!!
    and this the brillant!!! idea of garbage for the poor,
    Shame of you,

    1. Simple, yet very useful idea.

      What if you filled one with a non-toxic phosphorescent liquid?
      How long would it retain its light if stored in a mirrored box?

      That sounds ridiculous, but could you effectively extend daylight that way for a few minutes?


  12. I guess I feel stupid for thinking this was some sort of new innovative technical solution. Bravo to Marketing 2.0.

  13. Seems a simple reflector dish of some sort around it on the ceiling inside would make it even more effective. i’m sure people have already started jury-rigging those, too.

  14. Don’t some of you people actually watch the clip?
    Your questions and criticisms are answered in it.
    The flashing is sealed. No water gets in.
    The bottles last about 5 years.
    As to the off switch… lol, the night is the off switch.

    1. “The night is the off switch”

      LOL! When they need additional light there won’t be any!

      I like the idea of supplementing artificial light with innovative sources of natural light, but this is not the great advance it’s being presented as.

      1. You complain because it doesn’t provide light at night?

        They’ve lived for generations without “night light”; what they need is inside light during the day in their dark hut.

        You SO miss the point!

  15. A roof is for keeping out the rain. If you want light that is what windows are for. Putting lots of small holes in your galvanize is just looking for trouble come the rainy season.

    In my part of the world if you need electricity people use crocodile clips onto the nearest utility pole (there’s generally one nearby going to the rich folks homes).

    1. The typical slum dwelling this solution is designed for is thrown up using whatever is to hand and jammed tightly against the neighbors. Windows are not an option – similarly translucent roofing is out of reach for the poverty stricken. This obviates the need for electric light during the daytime – a huge saving for the poor.

  16. No disrespect for the bright folks at MIT, but they didn’t invent this. Back in the days of wooden ships, they would do the same thing to bring light to lower decks by insetting a glass block in the deck above. In order to cast the light evenly around the compartment, the lower part of the block was pyramidal. Turns out, they are called deck prisms, and surprisingly, can still be bought today, as curios, if nothing else.

  17. Whatever they are using to seal the hole in the roof, it likely will to dry, crack, and leak after a few years in the weather, however just put a bucket under it and you’ve go a water source and a light!

  18. This is great and all, but it’s just treating the symptom and not the disease, which is the fact that these people are living in such abject poverty that they have to build their homes out of first-world cast-offs.

    These sorts of things always leave a bad taste in my mouth. They feel like silly ways for westerners to alleviate guilt without actually doing anything about the underlying structural problems in third-world economies caused by centuries of exploitation.

  19. Another low-tech solutions is to send no electrity bills to “the poor”.

    It’s fast, easy, and it works.

    Or you also can pay “the poor” a decent wage in exchange for his work.

    1. Another low-tech solutions is to send no electrity bills to “the poor”.

      Sure- as long as you remember to also send along electricians, wiring and light fixtures. But then it’s no longer a “low-tech” solution.

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