New Twist on Power Walking

An anonymous reader writes "Carrying a newly designed backpack loaded with between 44 and 84 pounds of gear, users generate enough electricity to simultaneously power an MP3 player, a PDA, night vision goggles, a handheld GPS, a CMOS image decoder, a GSM terminal in talk mode, and Bluetooth."

Kangaroo

[awol]

Sounds a lot like the energy differential shown by hopping kangaroos. Their energy consumption is remarkably low given the velocities they generate and it seems to be the result of energy stored in their lower leg tendons. In other words they are using the same benefits to get a large increase in overall energy output with a marginal increase in metabolic consumption.

Re:84 pounds to power devices?

[timeOday]

Unfortunately, dismounted infantry have to carry around heavy backpacks most of the time, see for instance [smh.com.au]:

A typical operation lasts for five or six days in the field, requiring each man to bring 22 litres of water, ammunition and packs that can weigh up to 90 kilograms, along with an M-4 carbine and a 9mm sidearm. Other missions can go on for 10 days.

More and more, batteries only add to the problem... recycling some of the walking energy to reduce the need for batteries is a fantastic idea, getting it to actually work is even better.

Maybe next they can reduce the need to carry water by recycling urine!

Re:84lbs of what?

[Eivind]

It can be any load, it's just used for inertia. The device simply suspends the load on springs so it can slide an inch or so up and down the frame. Then energy is extracted from this movement. Very modest amounts of energy, I should add, around 7 watts.

For most applications this is a nonstarter: if it's daytime, solar would work better (since it'd work at rests too) and for many operations at nigth, simply carrying a battery is easier, because you want say your nigth-vision goggles to keep working even if you leave the backpack behind for some job.

why is this new? why a backpack?

[speculatrix]

why new?
self-winding watches have been around for many years to store energy in springs to power a watch, and Seiko and other companies have watches which store electricy in ultra-capacitors.

why a backpack?
why not use wrist- or ankle-mounted generators, which get a lot more movement, so presumably the generator could be a lot smaller and lighter?

Re:why is this new? why a backpack?

[promatrax161]

Well, on the other hand, if you would be running with a knee-mounted generator, perhaps it could make difference. Of course, you would not be running with a heavy backpack, but you might want to charge your batteries while jogging (which you might be doing anyway)?

Re:why is this new? why a backpack?

[promatrax161]

Exactly! Moreover, by spreading generators through the armor you can make the power supply more redundant, which is always good in combat.

Would this work for spacesuits during Mars exploration mission? I mean, OK, the joints are stiffer, but one would move also by jumping over large distances, due to less-then-normal gravity...

Meh

[Cthefuture]

You may generate 7 watts but if you are storing that in a battery you won't get that much back out.

It's a good idea though since a suspended load is going to be absorbing energy anyway (ie. the springy-ness), might as well use that to generate power.

However, a lot more energy could be generated by absorbing the person's weight (plus anything they carry). For example, if you could store the energy absorbed by the padding of your shoes as you walked. Now that would be some power.

Re:84 pounds to power devices?

[Divide By Zero]

Well, my mod points expired, so I'll have to just agree with you.

US Army's been developing computers for infantry for the last few years (I forget the code name, but it was typical Pentagon two parts macho two parts silly one part corny) and the stuff I read/saw said that the limiting factor was battery life. Rechargables are HEAVY. Tack that onto a 90kg pack that he's carrying anyway, and range gets shorter as your soldiers carry more If a grunt can power his laptop, field radio, GPS, and other electronics on the battlefield by walking and carrying the stuff he has to take anyway, and have that power generation help HIM to walk more efficiently, he can effectively power his gadgets for free AND get extended range by using less energy to walk/run. I can't see any way Defense ISN'T gonna be all over this like white on rice.

I've been somewhat involved in Geocaching, and one of the biggest complaints of cachers is running out of batteries for their GPS. One of the most popular trade items is spare AA batteries. If they can make this affordable to the consumer, and you can carry your water, trades, poncho, and whatever else you need for a day in the woods and power your Garmin or Magellan on the strength of that, that's huge.

Then there's the college kids with their newfangled eye-pods, high schoolers with cells, grade schoolers with game boys. They all carry a bunch of books everywhere they go. My high school backpack was 30-40lbs. That's a cell or PDA no prob. Retrofit a briefcase for Joe Yuppie to carry his paperwork and recharge his blackberry or laptop at the same time. Less time tied to an outlet, more time being on the road and productive (or so he'd have you believe). Get a small rig, put your mp3 player in it, strap it to your waist and go jogging. Kiss your low-battery warning goodbye. Make a tiny version and build it into a digital wristwatch, never change your battery again.

How are these people NOT going to be writing their own check?

Re:84 pounds to power devices?

[timeOday]

You don't recycle walking energy, you _drain_ extra walking energy, so it will be heavier to wealg, given the same total load. Have you ever ridden a bicycle with a dynamo-driven headlight? That's more or less the idea.

Or it might be more like regenerative braking - not energy for free, but putting energy to use that would otherwise be wasted.

The guy carrying the pack is already raising it by a small amount with every step (because it bobs as he walks). Thus he is doing work. If the weight is suspended, it won't bounce as much with each step, and some of the energy previously used to lift the pack will go into the batteries. At least hopefully that's how it works out.