I've sure you've all heard of the "Forever Flashlight" - basically, a flashlight that, instead of using batteries, is shaken to generate current and recharge a capacitor. I'm sure you all think it's pretty nifty.
Wouldn't it be nifty if ALL flashlights were like that? Better yet, wouldn't it be nifty if all battery-powered devices were like that?
Well, no reason why they couldn't be.
All that's necessary is to scale down the same inductive generator that runs the Forever Flashlight to the size, and shape, of a standard D-cell battery. (C and AA versions might be possible, but would be harder to operate and not last so long, so let's focus on the D-cell for now.) Then put contacts on the end, and voila! You can now insert this cell in any battery-powered device and shake it to generate electricity on the spot.
Sure, it may be more expensive than a standard battery, but it's the last battery you'll ever have to buy - and you don't even need to own a charger. You don't have to worry about leakage. Just put it in and forget it. Ideal for camping gear, emergency gear that will be left in a car trunk for years at a time, and any situation where you might need more power and don't want to be bothered to change the batteries repeatedly.-- gisho, Nov 18 2005 The Forever Flashlight http://www.thinkgee...adgets/lights/5a9f/For those of you who HAVN'T run into this epitome of niftyness before. [gisho, Nov 18 2005] Or we could put hundreds of ants on a treadmill inside a d-cell battery-sized cylinder. They would all have to be going the same way and this could probably be achieved by use of pheromones.-- jellydoughnut, Nov 20 2005 >Well, no reason why they couldn't be.
I like the basic idea, but am concerned that by the time you make room in a D-cell sized battery for the mechanics, there's precious little room left for the capacitor/rechargable battery. Your D-cell might run as long as an AA-cell, but in many applications maybe that's OK. I'm particularly amused by the thought of shaking a (personal massage) vibrator in order to have it vibrate ...
Still, + pending demonstration of impracticability.-- csea, Nov 21 2005 It least this is not another boys' bathroom idea.-- DrCurry, Nov 21 2005 This is a great idea. It does not really matter if the cell charge life is comprimised by a small capacitor as the main use would be for emergency or infrequently used devices.
I think that many manufacturers would be quick to discourage the use of these cells in many smaller, high-tech devices (Such as Digital Cameras and CD Players), however, as many devices will not have been tested/designed to be constantly and violently shaken...-- Minimal, Nov 21 2005 Perfect for Cordless Mice!
I also have an idea to recharge the batteries. If you do morning walk strap them to your legs(bcoz legs move a lot).-- kamathln, Nov 24 2005 You wouldnt be able to use it in many portable electronics; mp3 players PSPs etc.
-I replaced your old iPod battery with these new shake batteries.
-Hey where did my music go-- AlexTheGreat, May 15 2006 You could put them in a tumble drier with the heat off to recharge.-- caspian, Aug 14 2011 random, halfbakery