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?

How about a clock?

bwahaha.

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

Re:bwahaha.

In this house, we obey the laws of thermodynamics!

But who is going to control

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

But what will we do after peak gravity?

Way ahead of you buddy

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

But what will we do after peak gravity?

One guarantee: it's all downhill from there.

Bending Space-Time Lights the Way

"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?

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.

Waste of time and money

Simply building and shipping the 50 pound thing will probably consume more energy than it saves in its entire life. You are better off simply buying a high efficiency LED screw in bulb which are available right now for much less and do work.

Re:Looks cool...

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

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

Next thing you know...

you will have to start flipping your desktop over every few minutes ;-)

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

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:When I was a little kid I built a gravity go ca

Your story reminds me of the time when I turned an ordinary bicycle into a gravity-powered superbike. I still have a scar from that one.

Re:Looks cool...

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...

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?

Re:Looks cool...

Why not a small internal combustion engine coupled with the electric motor?

That way, you could still run the light in a power failure by running the small ICE.

Hey, you could make the engine a little bigger and add some outlets so you could power other lamps.

(The outside of my tooth is delicious.)

In the town of Bedrock...

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:In the town of Bedrock...

He could've made this even greener by incorporating a small bird ......

Would that be an African LED Light laden swallow?

Re:Looks cool...

Hey, don't you mean *vrooom*?

Re:Looks cool...

The idea sounds good to me too, but 50lbs. sounds like too much to put at the top of a lamp. I have young kids, and I don't want them getting crushed when they knock this thing over (as they almost certainly will). In addition, a lamp that requires 50lbs. of anything doesn't sound green on the construction side.

Re:Why not use a spring?

Probably could, but the overall lifetime of the device wouldn't be as long. Springs wear out over time, especially under heavy loads. The springs used in garage doors to assist you in pulling the door up (which were more common before everyone started installing power-operated doors) wear out after 10-20 years, for instance. I suspect each one of those springs -- there are typically 2 on a door -- each support 50 pounds or so.

I think part of the beauty of the mechanism is that it's really robust and long-lasting.

Just thinking about how you could build such a thing, I bet you could make a machine that had multiple ways of recharging/resetting it. My thought would be to have a lightweight 'sled' with a heavy removable weight on it. When the heavy weight is removed from the sled, a very small counterweight pulls it back up to the top of its track, so you can place the heavy weight back on. That's one way of resetting it, and the easiest provided you could pick up and lift the weight at once. The alternative would be to put a small crank on the sled's counterweight wire, which would allow you to slowly crank up the sled, with the counterweight on it. You'd end up doing the same amount of work but with a much smaller amount of force, due to the mechanical advantage of the crank.

That arrangement completely avoids using springs (it would only use counterweights) and would probably last a long time. I'm not sure whether it would be long enough to build some sort of 'Clock of the Long Now'-type device, but it would probably last a few human generations.

Re:Why not use a spring?

Another benefit is that scrap metal and rocks could be utilized as the weights -- IOW junk that's already "energy paid-for" rather than needing to be manufactured afresh, like spring steel.

As to the people whining about how it's too much work to move the weights... check your waistlines. 'Nuf said!!

Re:Looks cool...

Come on. I lift 50 pounds and much more many times most days... and I pay for it!
Think of it in terms of your health/fitness and gym membership fees you save.

Re:Looks cool...

either I'm having to lift 10 pounds 5 times every time I want to light the lamp, or I'm lifting 50 pounds.

Unless you are weakened by some medical condition lifting 10 pounds, 4 feet, 5 times in a row, every four waking hours isn't enough of a demand to be an issue. On the contrary I think this regular weight bearing movement might be a very good thing for the elderly or physically frail. [familydoctor.org]This could be viewed as an in-home several-times-a-day physical therapy light. Maybe a moveable stop, which could allow for the weight to start higher off the floor, but would need to be rest more often would be good addition for those with bad backs or knees that can't reach low to the ground. But to force people to get off the couch every two to four hours and move a few ten pound weights can really only be a benefit for the majority of the western world.

Re:Looks cool...

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.

Wet noodle?

You doubt the power of His Noodly Appendage?

Re:Looks cool...

Well, when you put it that way... I was worried about having to move 10 pounds. But 4.5 kg I can manage fine. Thanks!

Re:Looks cool...

Well, when you put it that way... I was worried about having to move 10 pounds. But 4.5 kg I can manage fine. Thanks!

I'd rather just lift 10 pounds of feathers.......

Re:Looks cool...

Give it a stand.

Set the stand on the floor, it has an arm that goes up to 50% of the height of the lamp and attaches to the back of the lamp. The lamp would be supported by the stand and wouldn't actually touch the floor. When the weight reaches the bottom, simply flip the lamp over by applying force to the upper portion. You could add in little catch or ratchet points so it would be easy to do.

Re:Looks cool...

"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?

Re:Looks cool...

so why has he not actually built the thing?

because it cant be made. You have a better chance at making cold fusion work or a perpetual motion machine than making this lamp do what was claimed.

first, there is no way for them to make enough energy even assuming 100% conversion to generate the electricity needed to power even 1 led for enough light to match that of a book light, many others here have covered this fact already..

Secondly the designer made HUGE mistakes in assumption is is a fact being missed by everyone else here debunking it.. Led's when rated in lumens are rated in their very narrow beam pattern, when you fire it into a lens/reflector to disperse the light to get an area lighting effect that his lamp is going for the lumens drop logarithmically. to go from the 15Deg beam pattern the LED's lumen output is measured at to a 270 degree pattern you will lose about 80% of the lumen output level.

So to get The claimed output, the device needs to generate a SHITLOAD more power, or increase the weight to be near 900 pounds or only operate for a few seconds at a time.

In other words, it does not work, cant work, and will never work. I think the guy is waiting for the laws of physics to be broken for his lamp to work.

I have been working with a company that designs LED lighting systems and most everyone get's confused because ratings on LED's are all over the road and not measured the same way as other lamp technologies.

This lamp if it used CFL lamps would have a far better chance at makign the claimed Lumen output than with LED's led's are still far-far less efficient than CFL lamps when it comes to area light output in beam widths wider than 20 degrees.

It can't possibly work either

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

A 40W Incandescent light bulb is ~2% efficient http://en.wikipedia.org/wiki/Incandescent_light_bulb#Luminous_efficacy_and_efficiency [wikipedia.org] , i.e. 0.8W of useful light.

White LEDS are currently ~65 lm/W and will possibly soon be 150 lm/W http://en.wikipedia.org/wiki/Light-emitting_diode#Operational_parameters_and_efficiency [wikipedia.org] so there is approx factor of 10 improved efficiency, so if the lamp can achieve 4W output he can match the 40W incandescent output. Even so this would require 57600J over 4 hours, which from a potential energy release from 1m would required a weight of 5000kg, so I think he fucked up his calculations or got a bit carried away.

Still, don't let science get in the way of art!

Re:It can't possibly work either

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

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

The drop is a screw so it's magnitudes more than 58".

And exactly how does having a screw generate more energy?

The path the weight takes to the ground is irrelevant.

An object weighing X lifted to a height of Y meters generates has a certain amount of potential energy, regardless of the path taken to the ground.

Re:You are way, way off

Sure, if you want the lamp to run for 4 minutes instead of 4 hours.

Watt is newton per second, not newton per minute. You forgot a divide by 60.

Re:It can't possibly work either

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

Re:A patent?

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?

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

Re:Home Gym..

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.

Alas

If only the machines in The Matrix knew this...

Re:Alas

Yeah, but if they had any sense, they'd have used cows, or they could have just pithed the humans; they don't WANT them thinking, they just need the meat bags.

Re:Next step ...

All you'd need is one that ran on heat, assuming you're not into necrophilia.

Re:Doesn't check out.

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

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.

He might not, but here's my work

He might not, but from what I gather, it's something like this:

PGE = m*g*h (potential gravitational energy in joules = mass * gravity * height)
50 lbs = 22.7 kg
PGE = 22.7 * 9.81 * 1.5 (I'm assuming a generous height of about 1.5 meters here, based on his diagram which gives 58" as the height)
PGE = about 334 joules

A joules is one watt-second, so 334 joules means 334 watts for one second, or 1 watt for 334 seconds.

According to Wikipedia, "The highest efficiency high-power white LED is claimed by Philips Lumileds Lighting Co. with a luminous efficacy of 115 lm/W (350 mA)." The claims is that this light can produce 600-800 lumens. If we take the lower number, 600, that breaks down to about 5 1-watt super-efficient LEDs to produce about 600 lumens.

So that's 5 watts per second, which with energy of 334 joules yields about 66 seconds of output. A far cry from 14,400 seconds (four hours).

Feel free to correct my math, it's been years since I've taken physics.

Re:!perpetual motion machine

Except that it doesn't. Do the math. One high output white LED needs 50mW for power.

Force x Distance/Time=W

22.6Kg x 1.47m x (9.8m/s/s)/14400s = .023mW

A brushless motor can operate at up to 90% efficiency, but the friction in the system will reduce the efficience a lot. We'll just say it runs at 60% efficiency. That's just 13.5mW. You need five of these to power an LED under current configuration. They want 600-800 lumens. So we'll lowball the figure with 600. Each LED can do about 80 lumens.

600/80=7.5, so 8 LEDs. That's 400mW of power for the system, or 30 generators.

Either you need 30 generators, a 680Kg weight, a 44.1m tall light (falling 30x's faster), OR a planet with 30x's the gravity. Your call.

Re:!perpetual motion machine

Run the numbers before you get too excited. IMHO they're full of crap. They're claiming on the order of 175 times more power than they actually have. Either the weight should weigh 4000 kilograms, or it should be lifted 250 meters into the air in order to put out 600 lumens for 4 hours.