ktulus cry brings news of a device that can power portable gadgets, prosthetic joints, and other mobile appliances by harvesting energy generated by walking. Researchers are working on making the device — still a moderately cumbersome 3.5 pounds — smaller while maintaining its energy harvesting capacity. CNet has a write-up with more pictures and a diagram of the device.
"In the mode in which the brace is only activated while the knee is braking, the subjects required less than one watt of extra metabolic power for each watt of electricity they generated. A typical hand-crank generator, for comparison, takes an average of 6.4 watts of metabolic power to generate one watt of electricity because of inefficiencies of muscles and generators. A lighter version would be helpful to hikers or soldiers who don't have easy access to electricity. And the scientists say similar mechanisms could be built into prosthetic knees other implantable devices such as pacemakers or neurotransmitters that today require a battery, and periodic surgery to replace that battery."
Walmart customers, I think if we can get them walking with these on, we'll solve all of our energy needs! Think about it. The entire country powered by fat, Cheetoes, Doritoes, Beer, etc.... And, with all of these large folks walking, they'll be in better health and therefore reduce the burden on our health care system ( one of the biggest expenses the Medicare has to deal with is kidney dialysis because folks fry their kidneys from hypertension. ).
A study in Holland [plosjournals.org] disagrees about the savings from obesity reduction:
Conclusions
Although effective obesity prevention leads to a decrease in costs of obesity-related diseases, this decrease is offset by cost increases due to diseases unrelated to obesity in life-years gained. Obesity prevention may be an important and cost-effective way of improving public health, but it is not a cure for increasing health expenditures.
A similar thing is going on with anti-smoking campaigns and mandatory seat-belt laws. With less people smoking, there are less people dying earlier of lung-related illnesses. With mandatory seat-belt laws, we're seeing a decrease in the number of viable organs for organ donation.
I'm not a smoker. But that's why I don't understand why so many of those socialist european countries are so against smoking, when they are so worried about "aging population" and creaking health services.
Sure discourage people from smoking, and educate them on the dangers. But don't make it impossible.
Tax tobacco enough and the smokers pay for their own "funeral" and everyone else's:).
If smokers survive past retirement age, they'll still be paying tobacco taxes. Give the best "donors" a cert of appreciatio
Actually, there is concern that this device may cause muscles to atrophy. It works by helping slow down your leg during the part of each step where your quadriceps "slow down" your leg. Similar to how electric cars use "regenerative breaking" to slow the car down and gain back energy.
In fact, theoretically when this device gets light and exact enough, walking can take less effort than without the device!
It is less than one watt of extra metabolic power when braking. I would assume (without RTFA) that this is analogous to regenerative braking in electric/hybrid cars.
Yes, you are right. This brace helps you to brake your leg, when you straighten it for next step. It uses your lower leg momentum to generate electricity.
It generates energy as the knee is using energy to slow your downward motion, hence the statement "less than one watt of EXTRA metabolic power for each watt of electricity".
Thats neat. But wouldn't it be more efficient for us slashdotters if it was put on our arms... Depending on which one is using the mouse... Or... Umm... The one not holding the lotion bottle?
Not Segway, Nautilus. Put an assembly of these suckers on all your major joints, dump the generated power into a resistor, and you have an exercise machine.
At least this finally makes some sense out of Naked Snake's whole "walk around to recharge the battery" thing. Does this device generate enough power to operate a soliton radar?
I do believe I remember someone saying on slashdot.jp yesterday something about 5 min of walking = 1 hour of battery time for a standard cell phone. So I would say probably.
When someone comes up with one that can convert talking into usable energy, let me know. I have several women in my office that could generate enough power to light a small country!
it's so heavy right now because they made all the parts easily replaceable to the scientists working on it. The scientist they interviewed on it also mentioned that if you stop wearing it, you tend to swing your leg harder for the first 3-10 steps, unaccustomed to the now-unpresent braking by the device. Really neat idea... while it makes sense to me, I didn't realize we actually braked our legs as we walked forward.
Someday all that exercise equipment in gyms will reclaim all their expended human energy into powering their own devices. Since even top performers like Lance Armstrong produce only 500W for under 20min [active.com], maybe we can just hope that exercisers can work off their lighting bill, if not heat their showers.
Hikers with a body suit, though, might be able to cook their dinner.
Actually, most gyms already do this - if you haven't noticed, most modern gym equipment (bikes, rowing machines, etc.) doesn't start up until you start using it.
Now, if we could find an efficient way to extract the extra heat produced during exercise from the human body, that would be awfully cool - the human would be able to perform longer, and the heat could be used for something useful. Turns out the human body is a terribly inefficient heat engine - according to NASA SP-3006 (I research human power as
On the efficiency of the human body as an engine, the number you quote is about right. However, assessing that as a terribly inefficient heat engine is a bit odd. A really well-tuned automobile engine, running on pre-refined fuel, might get 40% thermal efficiency or so. The human body, of course, starts with rather unrefined fuel (food, to the non-techie:-) ), runs all the necessary chemical conversion machinery, and produces its output. It also expends a lot of energy in self-repair and maintenance, whi
Gyms have lots of lights that are on even when the gym is empty, or when people are taking a rest. I think their body work could power those lights pretty well, offloading from the grid quite a bit. Maybe there's a way to capture that waste body heat to heat up the water in the showers that people take after exercising. If the mechanical work is captured efficiently as power for lighting, then those gyms could nearly disappear from the grid, except as backup. The elevators in NYC gyms probably keep the energ
Now, if we could find an efficient way to extract the extra heat produced during exercise from the human body...
I have an idea: we could put the humans in a little shell that captures their heat energy as they go about their lives. Come to think of it, it would make more sense if they were sedentary....and we could feed them through tubes....and make them think they were living free....oh, nevermind.
In the mode in which the brace is only activated while the knee is braking, the subjects required less than one watt of extra metabolic power for each watt of electricity they generated. A typical hand-crank generator, for comparison, takes an average of 6.4 watts of metabolic power to generate one watt of electricity because of inefficiencies of muscles and generators.
That is a bogus comparison, the arm and leg muscles are too different. A fair comparison might be bicycle based generator. Junk like thi
"Well less than one watt in and a full watt out makes me think not science as well."
statements like that make me think: try actually reading the article instead of just looking at the pictures.
the subjects required less than one watt of extra metabolic power for each watt of electricity they generated.
Try thinking harder. Your logic seems to assume that there is sufficient kinetic inefficiency to make up the difference. While this may be true for cars it is unlikely for a biological organism that
I think it was a fair comparison. How portable is a bicycle based generator? That and I imagine more people have been exposed to hand crank generators than they have bicycle based ones. It also doesn't say the device takes in less than one watt for every watt it puts out. It says the device required less than one watt of extra effort on the part of the wearer to get one watt out. In other words it's capturing some of the energy that would have been wasted anyways.
Really? I could be mistaken then. I would have assumed the pedal on a bicycle based generator would have been bigger than the whole unit for a hand-crank one.
Really? I could be mistaken then. I would have assumed the pedal on a bicycle based generator would have been bigger than the whole unit for a hand-crank one.
One implementation of the generator is a device that makes contact with a wheel and spins as the wheel rotates. These are very small devices. With regard to making a bicycle a stationary generator a hole and some minor carpentry skill will accomplish that. However I think that is a tangent. If you are going to walk to generate power you could proba
It also doesn't say the device takes in less than one watt for every watt it puts out. It says the device required less than one watt of extra effort on the part of the wearer to get one watt out. In other words it's capturing some of the energy that would have been wasted anyways.
Their measurements are naive. Respiration only indicates total energy consumption. It does not indicate a reallocation of energy within the body, for example digestion may have been slowed to provide additional energy. Further
As a guy who has had constant pain in his knees for the past 7 years, I am warning you that something like that may permanently damage your knee joint by simply forcing a minuscule change to the way your knee rotates while walking. I mean if unfitting shoes can hurt your knee, foot and hip joints (and they can) then this device may certainly hurt all of those joints as well if it forces you to change the way your legs are naturally moving.
Don't damage your joints, the pain may last for the rest of your life.
As a guy who has had constant pain in his knees for the past 7 years, I am warning you that something like that may permanently damage your knee joint by simply forcing a minuscule change to the way your knee rotates while walking.
The article states that the brace is activated only while the knee is breaking. Of course it's going to be painful if your knee is breaking. Duh...
Hello Slashdot community. My name is Max Donelan and I am one of the inventors of this energy harvesting technology. I thought I might try and clear up some of the misconceptions that people have about what we did. Here goes.
When you walk, your muscles are constantly taking some of your mechanical energy away from your body and dissipating it as heat. Other muscles (or even the same muscles at a later time) are acting to put mechanical energy back in to the system. This is a little like stop-and-go driving. Perhaps more accurately, it is like driving with one foot on the gas and one foot on the brake. While walking this way may not sound like a good idea, it is what we do. We can take advantage of the fact that walking is inherently uneconomical to generate electricity economically. The idea is to use a generator to help the muscles in taking away the mechanical energy. But instead of dissipating it all as heat like muscles, the generator also produces some electricity.
Here is a thought experiment that may make it a little clearer. If you stand up from your chair, your muscles that run down the front of your leg act to extend the knee. They increase your mechanical energy because by the time you are standing you have more gravitational potential energy. When you sit back down, the same muscles are active but now their job is to take the energy away from your body and dissipate it as heat (your kinetic energy is the same whether you are standing or sitting but your potential energy is less when you are sitting). Unlike traditional car brakes, your muscles require substantial "gas" (i.e. food) to decrease the energy of the system. And muscles are totally different than an electric motor - if you run an electric motor in reverse it takes mechanical energy and produces electric energy (i.e. a generator) but when you run muscles in reverse, they don't take mechanical energy and produce chocolate bars (i.e. food or chemical energy).
OK, back to the thought experiment. If we were to couple a generator to your knee motion, it would always resist the motion. So, it would make it harder to stand up and easier to sit down. It would produce electricity in both directions. What if we had some way to engage and disengage the generator and we disengaged it when you are going from a sit to a stand and engaged it when you are going from a stand to a sit. While this would only produce electricity for half the time, it would actually make the whole task easier. You can get electricity and lower the effort required to do the task! Of course this requires you to already have the need to do the task and that is why it makes more sense to do it during walking.
For the commenters that think it is too heavy, they are right. We are a year in to the next version and you can check it out on http://www.bionic-power.com/ [bionic-power.com] The graphic on the splash page will give you an idea of what it will look like. It will be less than 1 kg.
With regards to other energy harvesting technologies, I think they are all pretty cool. My favorite is the self-winding watch. The drawback is that it gets only about 5 micro watts. The shoes are all very cool and will likely serve a real need but they also get much smaller amounts of power. If you are already carrying a heavy load, the backpack is fantastic.
I am enjoying reading your comments so keep them coming!
Someone needs to work on their reading comprehension skills:
In the mode in which the brace is only activated while the knee is braking, the subjects required less than one watt of extra metabolic power for each watt of electricity they generated.(emphasis mine)
That means that the system captures some of the energy that would normally be "wasted" and converts it into electricity instead....
Does it double its output ... (Score:3, Funny)
Re:Does it double its output ... (Score:4, Funny)
Parent
Lots of applications ... (Score:4, Funny)
Sergeant: Private!
Private: Sir!
Seargeant: Walk faster! We're trying to reach HQ.
Re: (Score:2, Informative)
(In the US Army, at least, "sir" is reserved for male officers and warrant officers.)
Re: (Score:2)
Considering the the potential energy stores in... (Score:4, Interesting)
Re:Considering the the potential energy stores in. (Score:5, Informative)
A study in Holland [plosjournals.org] disagrees about the savings from obesity reduction:
Parent
Re: (Score:2)
Re: (Score:2)
Re: (Score:3, Interesting)
But that's why I don't understand why so many of those socialist european countries are so against smoking, when they are so worried about "aging population" and creaking health services.
Sure discourage people from smoking, and educate them on the dangers. But don't make it impossible.
Tax tobacco enough and the smokers pay for their own "funeral" and everyone else's
If smokers survive past retirement age, they'll still be paying tobacco taxes. Give the best "donors" a cert of appreciatio
Re:Considering the the potential energy stores in. (Score:4, Funny)
Parent
Re:Considering the the potential energy stores in. (Score:3, Insightful)
Re:Considering the the potential energy stores in. (Score:5, Interesting)
Actually, there is concern that this device may cause muscles to atrophy. It works by helping slow down your leg during the part of each step where your quadriceps "slow down" your leg. Similar to how electric cars use "regenerative breaking" to slow the car down and gain back energy.
In fact, theoretically when this device gets light and exact enough, walking can take less effort than without the device!
Parent
less than one watt for one watt? (Score:2)
Re:less than one watt for one watt? (Score:5, Informative)
Parent
Re:less than one watt for one watt? (Score:4, Informative)
Parent
Re:less than one watt for one watt? (Score:5, Funny)
That's simple: They violate the first law of thermodynamics, not the second one.
Parent
Re: (Score:2, Informative)
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Walking and running is a controlled form of falling forwards.
Maybe
Of course someone might be calculating a metabolic watt different from a plain old electrical watt for some reason.
Well... (Score:5, Funny)
In other news: (Score:4, Funny)
Re: (Score:2)
Not Segway, Nautilus. Put an assembly of these suckers on all your major joints, dump the generated power into a resistor, and you have an exercise machine.
rj
Metal Gear? (Score:2)
Re: (Score:2)
These stories are getting old. (Score:3, Funny)
they had a bit about this on NPR (Score:5, Informative)
Exercise Power Plants (Score:2)
Hikers with a body suit, though, might be able to cook their dinner.
Re: (Score:2)
Now, if we could find an efficient way to extract the extra heat produced during exercise from the human body, that would be awfully cool - the human would be able to perform longer, and the heat could be used for something useful. Turns out the human body is a terribly inefficient heat engine - according to NASA SP-3006 (I research human power as
Re: (Score:3, Informative)
A really well-tuned automobile engine, running on pre-refined fuel, might get 40% thermal efficiency or so. The human body, of course, starts with rather unrefined fuel (food, to the non-techie
Re: (Score:2)
Maybe there's a way to capture that waste body heat to heat up the water in the showers that people take after exercising. If the mechanical work is captured efficiently as power for lighting, then those gyms could nearly disappear from the grid, except as backup. The elevators in NYC gyms probably keep the energ
Umm likely no (Score:2)
http://hardware.slashdot.org/article.pl?sid=07/03/02/049254&from=rss [slashdot.org]
Re: (Score:3, Funny)
I have an idea: we could put the humans in a little shell that captures their heat energy as they go about their lives. Come to think of it, it would make more sense if they were sedentary....and we could feed them through tubes....and make them think they were living free....oh, nevermind.
None shall pass. (Score:2)
Compare against bicycle not hand crank ... (Score:2)
That is a bogus comparison, the arm and leg muscles are too different. A fair comparison might be bicycle based generator. Junk like thi
Re: (Score:2)
the subjects required less than one watt of extra metabolic power for each watt of electricity they generated.
Re: (Score:2)
statements like that make me think: try actually reading the article instead of just looking at the pictures.
the subjects required less than one watt of extra metabolic power for each watt of electricity they generated.
Try thinking harder. Your logic seems to assume that there is sufficient kinetic inefficiency to make up the difference. While this may be true for cars it is unlikely for a biological organism that
Re: (Score:2)
Re: (Score:2)
Smaller than a hand crank, and they generate enough energy to power a headlight. And that was with 1970s tech.
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One implementation of the generator is a device that makes contact with a wheel and spins as the wheel rotates. These are very small devices. With regard to making a bicycle a stationary generator a hole and some minor carpentry skill will accomplish that. However I think that is a tangent. If you are going to walk to generate power you could proba
Re: (Score:2)
Their measurements are naive. Respiration only indicates total energy consumption. It does not indicate a reallocation of energy within the body, for example digestion may have been slowed to provide additional energy. Further
You can get hurt by something like that (Score:5, Insightful)
Don't damage your joints, the pain may last for the rest of your life.
Re: (Score:2, Funny)
What's that? Oh, braking...
Never mind.
I just like it because ... (Score:2)
There's an abundant source of power here (Score:3, Funny)
Or how about a micro one that works off a woman's jaw muscles? No, wait, that means their cellphone batteries would never quit. Yikes!
Audio interview about the "Energy Brace" from CBC (Score:4, Informative)
http://www.cbc.ca/quirks/archives/07-08/feb09.html [www.cbc.ca]
The Interview (in OGG & MP3 formats) :
http://www.cbc.ca/quirks/media/2007-2008/ogg/qq-2008-02-09_01.ogg [www.cbc.ca]
http://www.cbc.ca/quirks/media/2007-2008/mp3/qq-2008-02-09_01.mp3 [www.cbc.ca]
Comment by one of the inventors (Score:5, Interesting)
When you walk, your muscles are constantly taking some of your mechanical energy away from your body and dissipating it as heat. Other muscles (or even the same muscles at a later time) are acting to put mechanical energy back in to the system. This is a little like stop-and-go driving. Perhaps more accurately, it is like driving with one foot on the gas and one foot on the brake. While walking this way may not sound like a good idea, it is what we do. We can take advantage of the fact that walking is inherently uneconomical to generate electricity economically. The idea is to use a generator to help the muscles in taking away the mechanical energy. But instead of dissipating it all as heat like muscles, the generator also produces some electricity.
Here is a thought experiment that may make it a little clearer. If you stand up from your chair, your muscles that run down the front of your leg act to extend the knee. They increase your mechanical energy because by the time you are standing you have more gravitational potential energy. When you sit back down, the same muscles are active but now their job is to take the energy away from your body and dissipate it as heat (your kinetic energy is the same whether you are standing or sitting but your potential energy is less when you are sitting). Unlike traditional car brakes, your muscles require substantial "gas" (i.e. food) to decrease the energy of the system. And muscles are totally different than an electric motor - if you run an electric motor in reverse it takes mechanical energy and produces electric energy (i.e. a generator) but when you run muscles in reverse, they don't take mechanical energy and produce chocolate bars (i.e. food or chemical energy).
OK, back to the thought experiment. If we were to couple a generator to your knee motion, it would always resist the motion. So, it would make it harder to stand up and easier to sit down. It would produce electricity in both directions. What if we had some way to engage and disengage the generator and we disengaged it when you are going from a sit to a stand and engaged it when you are going from a stand to a sit. While this would only produce electricity for half the time, it would actually make the whole task easier. You can get electricity and lower the effort required to do the task! Of course this requires you to already have the need to do the task and that is why it makes more sense to do it during walking.
For the commenters that think it is too heavy, they are right. We are a year in to the next version and you can check it out on http://www.bionic-power.com/ [bionic-power.com] The graphic on the splash page will give you an idea of what it will look like. It will be less than 1 kg.
With regards to other energy harvesting technologies, I think they are all pretty cool. My favorite is the self-winding watch. The drawback is that it gets only about 5 micro watts. The shoes are all very cool and will likely serve a real need but they also get much smaller amounts of power. If you are already carrying a heavy load, the backpack is fantastic.
I am enjoying reading your comments so keep them coming!
Re:Perpetuum mobile? (Score:5, Informative)
In the mode in which the brace is only activated while the knee is braking, the subjects required less than one watt of extra metabolic power for each watt of electricity they generated.(emphasis mine)
That means that the system captures some of the energy that would normally be "wasted" and converts it into electricity instead....
Parent
Re: (Score:2)
Sounds more like Maxwell demon
Re: (Score:3, Informative)