This will of course also work for other activities which flex the legs. See icon.

Whats a neurotransmitter and why does it need external power? Is it time to get my tinfoil hat on?

One for IT managers there I think

I'm sure I once read somewhere about an idea that would allow "knee jigglers" and "foot tappers" to charge their laptops by means of a device under the desk.. Wonder if something like that's available..? The last office I worked at I knew a chap that could power the whole bloody floor.

Recharge battery, Ipod, camera, PDA.

We are Borg, resistance is futile (pronounced fyoo dill)

Power neurotransmitters? Funny that, mine don't need charging every night (well, not in a socket anyway). But pray tell us, how does this device allow us to recharge our nervous system in chemicals?

Forgive me for adding an air of practicality to the proceedings, but unless you're wearing two of these, wouldn't this make for unevenly toned leg muscles, by reducing the impact of the exercise on the leg it's attached to?

And by extraction, even if you were to wear two (attractive as they are), aren't you going to have to walk/run further to get the same aerobic effect you used to due to it "helping the leg somewhat with its task"? Doesn't that defeat the object of the *cough* exercise of exercising?

It has military uses, personal communications, charging NODs and battlefield equipment etc. Expect the patent to be swallowed up by the Big Green Machine.....

"aren't you going to have to walk/run further to get the same aerobic effect you used to due to it "helping the leg somewhat with its task"?"

No - the device is extracting power from the system, so can only increase the amount of energy required, and thus the aerobic load. It may reduce the energy absorbed by the knees, but only because it absorbs that energy itself, rather than because there is less energy to absorb.

As far as I understand, your body is using energy to both 'push off' and take a step, as well as to stop your body collapsing to the floor at the end of a step. This device 'helps' the leg with this second part, absorbing some of the energy for itself.

You are still putting in the same energy when taking the step, but you are doing less work 'removing' that energy at the end. Kinda like adding gravitational potential and removing it each time your body takes a step; this device assists the removal of it. IANA expert in gait analysis, however.

"The last office I worked at I knew a chap that could power the whole bloody floor."

Sorry! :)

I'm also the annoying guy in the cinema..... my wife hates it.... wonder if paris is a knee jiggler

is for somebody to invent a pair of electric legs, so that less-active people can make use of this device too.

Of course, those legs will have to consume less than 5 watts to be REALLY useful.

... is to connect this to a vibrating phone and you can smile as you jog !!

no worries about my Bushnell Holosight quitting when I'm in the field. If I get two, that's ten watts, enough to keep a GPS and maybe even comms gear charged.

Beats carrying a few more pounds of batteries-more room for ammo!

My team has worked on similar things back to 03-04. We disclosed a very similar idea, but it is cool to see it put into practice.

If this thing is patented, then the patent is probably easily invalidated due to prior art. A problem is that people that work on energy harvesting come from all different fields and don't read the literature outside their own field.

It is in fact true that the device can improve the efficiency of the knee, but the real problem is weight. Adding weight to your body will increase your load regardless and probably more so than the "braking" gain in efficiency. And yes, you'd probably want one on each knee to keep it balanced.

Even at 5 W (which I doubt is a long-term, continuous power), it would take 10-12 hours of brisk walking to recharge a laptop. Forget about foot tapping to recharge.

I mean, in eco mode, my laptop is clocked at an average of about 9 watts (i have a proggie that measures battery discharge in mWh, and as a byproduct tells you the net power drain), and upto a little under 30w with every last possible gun blazing. This could be a nice topper-upper if, say, I was to travel somewhere and had it stashed in a backpack. Eight hours of walking around the city on & off, with the generated power also partially shared to phone, AA-trickle charger and mp3-cum-USBHDD could leave a nice two hours of photo backing up / uploading and the like without having to grovel to someone for use of their mains sockets or scrabble around in the murky, spider-infested depths behind the bunks in a hostel room.

Double them up and everything could get a guaranteed brimfull charge by the end of the day, and you'd get a tad more extra exercise into the bargain (maybe only 10% or so, but it's something).

Would it also work with cycling, to power the (white/red LED) lights without having to nob around with dynamos and stuff?

(Yeah, ok, my laptop is a low-drain ultraportable and was bought as such, so that it could both be used in a cramped train set (i measured; a 14" would be physically unusable on the birmingham commuter line, this 12" proved to be *just* usable), and so it could potentially last a workday of approx 50% use if I forgot/didn't have carrying space for/anywhere to plug in the charger, without needing a costly and cumbersome high-capacity battery (instead of it's 48Wh supplied compact one... now dipping below 30Wh after 2 years but still good for more than two hours off-charge). But, really, wouldn't that also be the machine of choice for a foot-travelling city rover, keeping the weight on their shoulders and bulk in their backpack to a minimum?)