Gravity Lamp Grabs Green Prize

eldavojohn writes "A lamp powered by gravity has won the second prize at the Greener Gadgets Conference in NYC. From the article, "The light output will be 600-800 lumens — roughly equal to a 40-watt incandescent bulb over a period of four hours. To "turn on" the lamp, the user moves weights from the bottom to the top of the lamp. An hour glass-like mechanism is turned over and the weights are placed in the mass sled near the top of the lamp. The sled begins its gentle glide back down and, within a few seconds, the LEDs come on and light the lamp ... Moulton estimates that Gravia's mechanisms will last more than 200 years, if used eight hours a day, 365 days a year." The article contains links to the patents and the designer/inventor Clay Moulton's site." I think my laptop would require a slightly larger weight to pull this off.

What's next for gravity power?

[friedo (112163)]

How about a clock?

bwahaha.

[notgm (1069012)]

i'm going to use the light from this lamp to power my photovoltaic weight lifting machine.

Re:bwahaha.

[nicklott (533496)]

In this house, we obey the laws of thermodynamics!

But who is going to control

[joeflies (529536)]

the consumption of gravity? Just imagine the peril if we use our precious resources like gravity on things like lamps, when we have coal to burn.

Will it still be cool to light up your lamp with gravity, when there's no gravity left and people are spinning right off the planet into outerspace? I guess it will eliminate the greenhouse gas issue by allowing the atmosphere to disappear when there's no more gravity left - but unfortunately it will also not allow people to live (the ones that are still on the planet after the other ones spun off into space as noted earlier)

Peak Gravity

[Tteddo (543485)]

But what will we do after peak gravity?

Way ahead of you buddy

[Sciros (986030)]

I've already started looking into buying "gravity offsets" and trying to use as much rope, glue, velcro, and static cling as possible.

Re:Peak Gravity

[griffjon (14945)]

But what will we do after peak gravity?

One guarantee: it's all downhill from there.

Bending Space-Time Lights the Way

[MSTCrow5429 (642744)]

"The acrylic lens will be altered by time in an attractive fashion, Moulton said. "The LEDs produce a slightly unnatural blue-ish light. As the acrylic ages, it becomes slightly yellowed and crazed through exposure to ultraviolet light," he said. "The yellowing and crazing will tend to mitigate the unnatural blue hue of the LED light. Thus, Gravia will produce a more natural color of light with age."

He predicted that the acrylic will begin to yellow within 10 to 15 years when Gravia is used in a home's interior room.

Why would I buy a product that takes 10-15 years to become tolerable for normal household use, when in 10-15 years, either this technology will be updated so that it comes with natural light out of the box, or new competing technologies develop that do the same thing, without the color drawback?

Hmmm. What else falls around the house?

[ScentCone (795499)]

Got me thinking about how, in a two-story house, there's all sorts of vertical movement. I was picturing a way to step on a platform (sort of like those that parking lot attendants sometimes use) to ride from the second floor to the first. That buffered ride down could throw some energy into a flywheel. And, how about all of the greywater from upstairs? Three people taking their morning showers send many pounds of water down a vertical path to ground level. I wonder if passing that through some sort of screw drive might give up a few watts.

Re:Looks cool...

[edittard (805475)]

Say what?!? Why on earth would they tell you that?

This is slashdot, we have articles here, not thinly disguised advertisements.

Re:Looks cool...

[eln (21727)]

I really like the idea, and would probably buy one if the price is right.

However, one thing concerns me. The weights are moved up to the top by human power, which is fine, but according to the picture on the designer's website, the weights are 5 10 pound weights in each lamp, so either I'm having to lift 10 pounds 5 times every time I want to light the lamp, or I'm lifting 50 pounds. Perhaps he could incorporate some sort of foot pedal mechanism or something to more easily lift the weights. If he could figure out how to do that, and also maybe improve the efficiency a little more to get more than the 40-watt equivalent it gets now, I could see this becoming a solid replacement for traditional lamps.

Re:Looks cool...

[Angostura (703910)]

Perhaps he could incorporate some sort of foot pedal mechanism or something to more easily lift the weights.

I can't really see why a small electric motor couldn't be incorporated into the design to do this, surely it would be much more convenient?

In the town of Bedrock...

[StCredZero (169093)]

He could've made this even greener by incorporating a small bird or monkey whose job it was to crank this to the top. This way, the people of the world are motivated to preserve wildlife so that they can read novels at night.

Re:Looks cool...

[PFI_Optix (936301)]

For the average male, yes. But this is slashdot. One only needs the strength of a wet noodle to post here, and actual exercise is frowned upon. As is leaving the basement for fresh air and/or a little sun.

Re:Looks cool...

[TheLostSamurai (1051736)]

"Concept illustrations of Gravia" "Moulton estimates" "He predicted"

As far as I can tell this is nothing more than vaporware. There doesn't seem to be any indication in the article that this thing has actually been built. While is does seem like a cool concept the overall implementation does not seem that complicated; so why has he not actually built the thing?

It can't possibly work either

[Maddog Batty (112434)]

22.6 Kg x 1m x 9.8 m/s^2 / 4 hours = 0.015W if conversion is 100% efficient (which it won't be)

The red led on the front of your modem requires around this amount so the glow will be feable. To get the equivalent of a filament 40W bulb requires around 10W so the system is only around a factor of 1000 out.

Re:It can't possibly work either

[Kijori (897770)]

22.6 Kg x 1m x 9.8 m/s^2 / 4 hours = 0.015W if conversion is 100% efficient (which it won't be)

The red led on the front of your modem requires around this amount so the glow will be feable. To get the equivalent of a filament 40W bulb requires around 10W so the system is only around a factor of 1000 out.

Your conclusion is right, but your figures are a bit out. The drop is 58" according to the plan [core77.com]. This gives about 0.022W at 100% efficiency.

For reference, the highest efficiency LEDs that I know of get 131 lumens per watt. If we're generous and allow them 150 lumens/watt, they still need 4W of power. This would require a drop of 255 metres using the 50lbs of weights he claims. Since we can't really go above 1.5m high, we'll need almost 4 tonnes of weights.

A shame really, I'd have rather liked one.

Re:It can't possibly work either

[Jonas the Bold (701271)]

Ok, what the hell. Exactly what kind of worthless prize or conference is this, that they didn't check to see that you need 1000 times the energy the weight could possibly provide? And exactly what kind of scientist designed this thing that can't possibly work?

Meanwhile they're talking about how it would last two hundred years. Right. That's what they spent thier time with, trying to find a way to convince people how incredibly green this thing is.

I hate this sort of environmentalism that has absolutely no regard for reality. This one has no regard for basic conservation of energy, they might as well have said we can solve the energy problem with perpetual motion.

Re:It can't possibly work either

[spinfan (893209)]

Upon further inspection, it turns out the 50 lb mass is actually 50 6-volt lantern batteries. Oops.

When I was a little kid I built a gravity go cart

[MrJerryNormandinSir (197432)]

I never won a green prize for that.

I guess I was ahead of my time.

All I remember was.. the brakes didn't work, and I felt pain for 2 weeks.

Re:A patent?

[by Anonymous Coward]

You don't know the difference between a lamp and a clock?

One tells time, the other emits light. I thought that was fairly obvious.

Re:A patent?

[aztektum (170569)]

Duh! Because it's a *light* powered by weights!

Re:Home Gym..

[krlynch (158571)]

how long before the home gym captures energy for your home.

Never :-)

Humans can not produce large amounts of sustained output power, even when exercising. A "healthy human" can probably push out 300W for about 20 minutes [ohiou.edu] before they collapse from exhaustion. Even if you can convert all of that to electricity and store it for later use at something like 50% efficiency (which would be staggeringly high), you're only talking about 0.05kWh of usable energy. You could do much better if you were willing to exercise at much lower intensity for much much longer periods of time (but who would do that just to light a minuscule handful of light bulbs). But you're really not going to ever get usable amounts of power out of your daily exercise routine.

Re:Doesn't check out.

[retep (108840)]

Yup, they say it emits 600-800 lumens.

Given that LEDs emit about 100 lumens/watt, that's say, 6 watts, * 4 hours = 86,400 joules They claim it's about 2m high.

Plugging those two values into the gravitational potential energy calculator at http://hyperphysics.phy-astr.gsu.edu/Hbase/gpot.html [gsu.edu] gives a weight of about 5000kg, slightly above the claimed 22kg...

Physics for designers

[James McP (3700)]

You sir, are correct.

There's 50lbs of weight that fall about 4ft, if I'm reading the diagrams right. That's 200 ft-lbs. Which comes out to... hmm... 0.075 watt-hours. Over 4 hours that means 0.019 watts continuous power. From memory really good blue LEDs are around 200 lumens/watt so .....3.8 lumens. A candle is ...13 lumens. So it's about a third of a candle. An ideal light source is ~680 lumens/watt would be 13 lumens, or a candle.

To get ~700 lumen light at 200 lumen/watt would require 3.5 watts of power, over 4 hours is 14 watt-hours or 3700 ft-lbs. Over 4ft of fall that amounts to 925 lbs. My goodness, that is a group effort.