Just read about this knee-joint powered generator. The story is that this device is built around a sports knee brace. It uses the "wasted" energy of your lower leg swinging as you walk. The claimed output of 5W is enough to fully charge a 2300 mah NiMh battery in half an hour of walking. It's not ready for production yet, but it looks much more promising than any of the other techniques for generating power from the human body.
Especially for the backpacking crowd far from a recharger of the plug in variety <img src="/forums/images/graemlins/grin.gif" alt="" /> Good post Nity, as usual <img src="/forums/images/graemlins/smirk.gif" alt="" />
PEPPER SPRAY AIN'T BRAINS IN A CAN!
Loc: Ozark Mountains in SW Missouri
That is a cool concept. I'm a little surprised by the weight, (3.5 pounds) because it looks quite small.
Here in the Ozarks you're walking downhill at least half the time, so I bet they'd be fun on the downhill side and may even save you a little energy while charging up your GPS.
For hikers there should be something better though. I mean it just seems a little out of place and clunky. Let's put our heads together and see what comes of it. Here's a shot at it...
Think about what you could do with a spring (or magnet) loaded push rod in the bottom of a hiking pole. Batteries charging in the handles... That approach seems more intuitive to me (for hikers). Has someone done that already?
If not, I'm over the whole "someone stole my idea" thing. Now I'm more into the "If I tell everybody maybe someone will do all the work and I can get one for cheap when they've got it on the shelves" thing, so let me know if you make it because I might buy one. <img src="/forums/images/graemlins/grin.gif" alt="" />
Loc: Ozark Mountains in SW Missouri
Yeah, you got it! I think that if you moved a rod on the bottom of a hiking pole about an inch with each stride you could probably generate some juice.
You should be able to use the same method as the flashlights you shake by just adding a spring or magnets to keep the rod down when there is no weight on it.
There might be more efficient methods as well. Since you have some decent force to harness when the pole is set down you might be able to create a decent jolt.
When I was a kid I used to play with donut shaped magnets place on a dowel rod. They would be stacked so the polarity made them "Float" above each other and when you pushed down on the top magnet they all would compress down. Seems like there's energy to be captured in that movement too.
It's sure a simple concept, that makes exploring the options fun. Should be inexpensive to prototype too. Shoot, I have one of those flashlights sitting around here somewhere and I love to take stuff apart and modify it for other purposes. I'll have to look around for a piece of aluminum tube.
Even if you only put a LED light in the handle of the pole to use as a lantern it'd be a fun gizmo to have. Maybe an LED and a power port for external devices <img src="/forums/images/graemlins/wink.gif" alt="" />
The generator's weight is in the magnets and windings. To generate 5W average from 1/2 of the leg's motion, the generator must be capable of at least 10W output, and that's going to be several pounds for an off-the-shelf component. Once it's customized for the application, it might drop to under a pound.
Jumping on the dream wagon for a minute - if some of your muscle cells were cultured and attached to a small linear generator, then implanted in your body with electrodes to stimulate them, you could generate your own electricity. Might have to bring more food on the trip though!
Regarding your hiking pole generator - a variable field linear generator (kind of like those flashlights, except the magnet is replaced by an electromagnet) would allow a "damped" feeling to the pole, rather than a "springy" feeling. The only drawback would be the added weight. Hiking poles that are heavy can be tiring to use.
But the one idea that I'd develop if I had the time and money is a device that would have a part that fit in the mouth. Chewing on the device would generate electricity, and as many gum addicts will attest to, chewing takes very little thought.