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A $5 Lamp Powered Solely by Gravity

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Re: A $5 Lamp Powered Solely by Gravity

#21

Post by zem »

Lagged2Death wrote: post #10

Some people get excited by F1 racing, the Bugatti Veyron, or stuff like the latest iPhone, telling you they are technology enthusiasts or engineering fans. But if you ask me, it's always at the low end of things - like this project - where the really inventive, exciting engineering happening. Sure, something like an F1 car is impressive after a fashion, but considering the price, yeah, well, it better knock my damn s…

indeed! having lived in india, i get particularly excited by projects that could provide grid-free lighting and clean water to rural areas.

also, a quick plug for my blog [http://aleverlongenough.wordpress.com/] rounding up projects like this - it was unfortunately short-lived because life got busy, but i hope to restart it in 2013.

Re: A $5 Lamp Powered Solely by Gravity

#22

Post by daeken »

Lagged2Death wrote: post #10

Some people get excited by F1 racing, the Bugatti Veyron, or stuff like the latest iPhone, telling you they are technology enthusiasts or engineering fans. But if you ask me, it's always at the low end of things - like this project - where the really inventive, exciting engineering happening. Sure, something like an F1 car is impressive after a fashion, but considering the price, yeah, well, it better knock my damn s…

> it's always at the low end of things - like this project - where the really inventive, exciting engineering happening.

That's why I got into the demoscene. While I'll drool over the crazy new demos pushing the latest GPUs to the limits, it's always more impressive to me when people take extremely limited systems and file sizes and do incredible things with them.

Re: A $5 Lamp Powered Solely by Gravity

#23

Post by NathanKP »

Maybe I'm stupid for asking but what is the advantage of this over a spring powered wound clock? My wristwatch can tick for two days on a wind, and while it isn't as cheap as this gravity powered wound clock I'm sure it could be made cheaper. There is nothing special about this invention; purely mechanical "gravity powered" clocks have existed for centuries in the form of old grandfather clocks etc.

Re: A $5 Lamp Powered Solely by Gravity

#24

Post by duskwuff »

tonyarkles wrote: post #5
ColinWright wrote: post #2

Previously submitted and seriously doubted: http://news.ycombinator.com/item?id=4889266 In that thread[0] revelation[1] said: At perfect efficiency, this seems to give you about 55mW for a hour, if I asked Wolfram correctly (for 20kg lifted one meter) - [2] - So probably a hoax. [0] http://news.ycombinator.com/item?id=4889426 [1] http://news.ycombinator.com/user?id=revelation [2] http://www.wolframalpha.com/input/?i=…

If you read some of the followups and tweak the math a little bit, it works out reasonably well. Instead of 20kg and 1m, 20lb and 2m, which comes out about the same (49.42mWh). If you have to lift it every half hour, that's 100mW for a half hour. That's more than enough power to get a useful amount of light out of an LED. For example, this LED uses 68mW https://www.sparkfun.com/products/531 and is marketed as "so bri…

That's assuming a perfectly efficient dynamo and no mechanical losses. (Which are both huge assumptions.)

Re: A $5 Lamp Powered Solely by Gravity

#26

Post by ars »

tonyarkles wrote: post #5
ColinWright wrote: post #2

Previously submitted and seriously doubted: http://news.ycombinator.com/item?id=4889266 In that thread[0] revelation[1] said: At perfect efficiency, this seems to give you about 55mW for a hour, if I asked Wolfram correctly (for 20kg lifted one meter) - [2] - So probably a hoax. [0] http://news.ycombinator.com/item?id=4889426 [1] http://news.ycombinator.com/user?id=revelation [2] http://www.wolframalpha.com/input/?i=…

If you read some of the followups and tweak the math a little bit, it works out reasonably well. Instead of 20kg and 1m, 20lb and 2m, which comes out about the same (49.42mWh). If you have to lift it every half hour, that's 100mW for a half hour. That's more than enough power to get a useful amount of light out of an LED. For example, this LED uses 68mW https://www.sparkfun.com/products/531 and is marketed as "so bri…

It's hurts to look at it because it's focused into a very narrow beam. Very bright sure - in one tiny spot, and totally useless to illuminate a room.

They even include a photo of the beam pattern - it's almost as focused as a laser.

(You can tell on an LED by looking a the top - round tops are focused, flat ones spread out.)

Re: A $5 Lamp Powered Solely by Gravity

#27

Post by ZeroGravitas »

Lagged2Death wrote: post #10

Some people get excited by F1 racing, the Bugatti Veyron, or stuff like the latest iPhone, telling you they are technology enthusiasts or engineering fans. But if you ask me, it's always at the low end of things - like this project - where the really inventive, exciting engineering happening. Sure, something like an F1 car is impressive after a fashion, but considering the price, yeah, well, it better knock my damn s…

"To define it rudely but not inaptly, engineering is the art of doing that well with one dollar which any bungler can do with two after a fashion." -- Arthur M. Wellington

Re: A $5 Lamp Powered Solely by Gravity

#28

Post by joeyh »

I use kerosene lights by choice in the winter in weeks like this one when there is no sunshine. So, here's my firstish world problems take on it. May not apply to people for whom a gallon of kerosine is a significant fraction of their monthly income.

I have a hard time seeing myself using something like this, except as task lighting. I'd be fine to have to lift a weight if I was only going to be using the kitchen for 30 minutes (it could even serve as a useful timer), or similar. But getting up every 30 minutes rules out using it anywhere I need longer duration light for eg, reading.

Also, anywhere I could use this, I could use any of the many inexpensive crank LED lamps available everywhere, which run for similar amounts of time.

The pity is that, with the right design, this could support a longer cord for a further lift distance, so it'd run an hour. Or multiple weights used in sequence or parallel so it can be primed for even longer (iirc that's how my grandparent's cuckoo clock worked). From what I can see, it's not designed to be very hackable, and something like this needs hackability.

The LED light is the other problem with it; I'd much rather have a well ventilated kerosine light than blue tinged LED for almost any task. (I'm curious to see studies about kerosine health risks however.) Since this light cannot be moved, it has to illuminate the whole area, and its light doesn't seem up to it, so I'd be doubtful about eg, reading by it either.

Re: A $5 Lamp Powered Solely by Gravity

#29

Post by nuclear_eclipse »

pyre wrote: post #8
dsl wrote: post #4

Not to nitpick, bit it's not powered by gravity, it is powered by people going over every 30 minutes and lifting a weight back up to its top position. EDIT: Apparently people don't understand that using gravity to generate energy is a thing, and the title "Powered Solely" suggested someone found a way to do that.

Gravity is the storage mechanism. When someone says something is battery-powered, do you start an argument about how that technically isn't correct?

Gravity isn't the storage mechanism; the ballast bag is. Gravity is the mechanism used to unleash the stored energy, the same way that the electro-chemical voltage difference between the two components of the battery is the mechanism that unleashes the stored energy in the battery. If anything, it's a ballast-bag-powered light.

Re: A $5 Lamp Powered Solely by Gravity

#30

Post by ars »

pdonis wrote: post #6
ColinWright wrote: post #2

Previously submitted and seriously doubted: http://news.ycombinator.com/item?id=4889266 In that thread[0] revelation[1] said: At perfect efficiency, this seems to give you about 55mW for a hour, if I asked Wolfram correctly (for 20kg lifted one meter) - [2] - So probably a hoax. [0] http://news.ycombinator.com/item?id=4889426 [1] http://news.ycombinator.com/user?id=revelation [2] http://www.wolframalpha.com/input/?i=…

Um, please read the entire previous thread before dismissing this as a hoax. As you can see from a number of posts that I and others made there, the light is comparable to a kerosene lamp, which is what it's intended to replace. It is not, of course, comparable to the kind of light we in developed countries are used to, but that's not what it's intended for.

Using the numbers above and the typical LED efficiency you get 5 lumen of light per half hour ASSUMING perfect mechanical efficiency.

http://www.wolframalpha.com/input/?i=20+kilogram%E2%80%90for...

A simple wax candle produces 11 lumen. And there is no way you will get anywhere near perfect efficiency.

So at best, this will product maybe 1/3 of the light from a candle.

If you directed that light into a small spot, it could be useful, but of course it's a large device and you can't do that.

If you illuminated a room with it it would be enough to walk around and not crash into things, but not enough to read.

Another comparison: Assuming a 2 meter by 2 meter room (which is tiny), this would produce 1.3 lux (again, assuming perfect efficiency).

Moonlight produces betwen .25 and 1 lux.

So at best, with reasonable efficiency, and assuming a tiny room, this is comparable to moonlight under a full moon.

Can you read in moonlight? Go try.

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