Half a croissant, on a plate, with a sign in front of it saying '50c'
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Things with Strings

Updated version of the old talking doll
  (+18, -1)(+18, -1)
(+18, -1)
  [vote for,

Once upon a time a lot of dolls were made that had a voice powered by pulling a string. This string wound up a spring, and as it unwound, the doll would say one of several possible sentences.

Nowadays we use battery-powered electronics for many things including talking dolls. However, batteries die and must be replaced. I submit that this nuisance factor will encourage sales of this Idea.

On TV there are advertisements for flashlights that you can shake for a few seconds, and then it shines a light for several minutes. It works because the flashlight contains a reciprocating generator, and the output of that generator is stored in a capacitor. The LEDs of the flashlight use only a small amount of power, compared to the generated amount, and this is how several minutes of light can be produced. (One flashlight I've seen has a crank; it says to crank for one minute to get 40 minutes of light. Cool!)

Well, the kinds of generators I've seen so far, for these kinds of low-power gadgets, are too bulky. You don't want to add a big crank to your cell phone, for example! But what about a small generator? Here's the Idea....

A small rotary generator (maybe 2 centimeters cubed) has its axle connected to a flywheel and a racheted pulley. This pulley also has a spring. A string is wound around this pulley, and the end of the string is attached to a pull-ring. So you pull the string pretty hard, and the generator spins up to a pretty high speed. It keeps spinning after you reach the end of the string because of the flywheel and ratchet. The spring allows the pulley to pull the string back. And while the generator is spinning, it is charging an appropriate sized capacitor. This extraction of energy eventually stops the spinning generator, but the now-well-charged capacitor should be able to run the gadget (cell phone, iPod, flashlight, CD player, etc) for a significant time, before the string needs to be pulled again. The weakest part of this Idea is probably the string; it needs to be as tough as Kevlar to be pullable for hundreds or thousands of times without breaking.

Vernon, Jun 02 2006

//You don't want to add a big crank to your cell phone, for example!// http://www.britishe...op=imgLib-viewImage
...Um [fridge duck, Jun 02 2006]

Here is is! (as a generic portable charger) http://www.gizmag.c...or-its-power/13798/
Only took 3-4 years to get produced, heh. [Vernon, Jan 11 2010]

This is how they talk. http://entertainmen...rks.com/see-say.htm
[VJW, Jun 28 2011]


       Forget the flywheel, too heavy if you want to get a good amount of power out of it. How about a strong spring that slowly drives a generator when flexed with the string?
GutPunchLullabies, Jun 02 2006

       UB, we know you are!   

       only kidding honey - have a lot on my mind!
po, Jun 02 2006

       [GutPunchLullabies] - what kind of name is that? A reincarnation of Philip Dick? I like your amendment to the idea.
Zimmy, Jun 03 2006

       The string is definitely better than shaking. Teaching young kids to shake their baby dolls ought to be avoided.
Ling, Jun 03 2006

       [UnaBubba], thanks.   

       [GutPunchLullabies], a flywheel need not be big/massive to be effective/useful. Perhaps you remember some toy cars that you would roll along the floor and then let go? They had small flywheels that your initial motion revved up, and provided the energy to keep those small cars moving. And those flywheels are pretty much what I had in mind here. And regarding your strong-spring notion, I agree it could work, but I feel it adds extra complexity. Also, it is the equivalent of the mainspring of a mechanical watch, and I hesitate to tell you how many watches/clocks I've broken by over-winding them. A pull-string would make over-winding/breaking that spring far too easy! Next, getting the mechanical power into the form of stored electricity can be done either quickly or slowly, when the storage device is a capacitor. And about the same amount of energy will go in, either way. The simpler method will yield the most stored energy (less wastage to mechanical complexity/friction-losses).
Vernon, Jun 04 2006

       Well, if the energy can be generated slowly or quickly, why the flywheel? Why not just pull a lot of current out of one slow, hard pull?   

       Also, what does my name have to do with PKD (RIP)? , [Zimmy]?
GutPunchLullabies, Jun 05 2006

       "Why not just pull a lot of current out of one slow, hard pull"   

       Two reasons. First, people are lazy. Second, the difficulty of the pull is related to the load. A hard pull implies a big load, which in turn implies a big generator and big other stuff, including the overall gadget. So, if the capacitor-charging circuit can only handle a modest load, and you can pull harder than that, you need a temporary energy-storage device, like a flywheel.
Vernon, Jun 05 2006

       This is really good. +   

       Since people are so into the look of their phones you can do a lot of designs/colors for the pull-ring.
pigtails_and_ponies, Jun 06 2006

       Yeah, that makes sense that you would need a bigger generator to capture more electrons at once. My first impression was that you would need to capture the energy slowly, I just wasn't sure why.   

       But how about this: Use the energy of opening or closing the phone to spin up the flywheel/crank the spring.
GutPunchLullabies, Jun 06 2006

       I have no objection to additional power sources, if it helps to keep the unit running when you need it to be running. A cladding of solar cells, for example. But very likely none of those will provide as much power as a pull-string could.
Vernon, Jun 06 2006

       I dunno. It seems a little too easy to break for reasons mentioned above. How about having a small flywheel sticking partway out the side, and have it revved every time you pull it out of your jeans pockets? It could be revved on a flat, hard surface as well, just like one of those little toy cars.
qt75rx1, Mar 17 2008

       Having grown up with those toy cars, I think it would be fun to charge up your phone in this manner before making a call. And you could get auto skins for the phone as well.
normzone, Jan 11 2010

       wow. Good one. [+] Girls get the talking tina version, boys get the revved-up-like-a-deuce version.
fishboner, Jan 11 2010

       [+] ::singing::: ...brown paper packages and things that have strings... these are just some of my favorite things.
Jscotty, Jan 12 2010

       How do those dolls used to generate speech using a spring ? was it autophonograph thing ?
VJW, Jun 27 2011

       yes. <link>
VJW, Jun 28 2011

       + yes...where has [Vernon] gone?
xandram, Jan 24 2021


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