this wud certainly interest u

[jam_mafia]

hello everyone,
this is my first post in this group hope it would be honoured.i have seen a mobile charger which basically charges the mobile when you jog or walk.you read it right.i donot know the circuit through which i could make this happen.i am very much interested in doing this project,i have a very vague idea that a transducer would be used in this circuit.
i request the members of the group to please help me out of this situation.i am a final year student in electronics stream i would love to get replies for this post because that thought keeps on haunting me please HELP!!!!!!!!!!

 

[akg]

hello everyone,
this is my first post in this group hope it would be honoured.i have seen a mobile charger which basically charges the mobile when you jog or walk.you read it right.i donot know the circuit through which i could make this happen.i am very much interested in doing this project,i have a very vague idea that a transducer would be used in this circuit.
i request the members of the group to please help me out of this situation.i am a final year student in electronics stream i would love to get replies for this post because that thought keeps on haunting me please HELP!!!!!!!!!!

the charger u explained above is not in the public market yet , yes but it can be done .

during walking : there appears a alternate pressure difference in our shoes , this mechanical motion can be converted to elec: using peizo(?) .
another thing we have a vertical motion during walking , magnet along with a current generating coil can produce ele:

In all these methods the current produced is small .. u need to refine the technique to generate enough electricity . but these are the basics

 

[chemelec]

Considering your arm movement as you walk:
And Attaching a simple Coil to a moving magnet on a pendilum. So the magnet passes through the coil as your arms swing back and forth will also work to generate electricity.

 

[jam_mafia]

cud u provide a concrete circuit so that i wud get into action????? :?:

 

[mstechca]

what happens if one takes a small, unshielded dynamic speaker, and consistently pushes the center of it?
Doesn't that create an AC voltage?

 

[chemelec]

what happens if one takes a small, unshielded dynamic speaker, and consistently pushes the center of it?
Doesn't that create an AC voltage?

Yes it does. Actually a Speaker acts as a Microphone.

Problem is the Movement through the magnetic field is too Short and also the Coil is too small to generate much voltage.

 

[audioguru]

what happens if one takes a small, unshielded dynamic speaker, and consistently pushes the center of it?
Doesn't that create an AC voltage?

Shielding a speaker's magnet doesn't affect how it works internally.

Connect the wires of two DC motors together. Without a load, when one is spinned then the other one also spins from the power (miniscule) that is generated.
Put an electrical or mechanical load on them and you will see the extremely low efficiency.

Connect the wires of two speakers together. Scream at one speaker and see if you hear much from the other one. Not much.

All of these "generator" methods don't generate enough of anything when they have a load.

A battery is charged with power, not just voltage.

 

[Oznog]

They're probably doing the same thing as the "shakelights". Induction coil and a cylindrical neodymium magnet that can slide back and forth through it.

For walking, a more practical solution might be to hang the magnet vertically from a strong spring and tune its oscillation to try to resonate with a walking pace.

Really the power output is quite low though. The shakelights sort of exaggerate because the LED, which doesn't require a lot of power to begin with, runs at full intensity for only a brief time and it tapers off so technically the LED is lit almost indefinitely though not at a useful level. It would only be a tiny fraction of the current usually used to recharge an iPod or cellphone.

Easy to play with though, just get a big shakelight from Fry's, and probably modifying it with the vertical spring would be the best idea.

 

[jam_mafia]

circuit plzzzzz

i thank everyone who have posted but i need a circuit diagram on the topic if u guys cud help me i wud be happy!!!!
thanx,waiting for the circuit so that i can get into action!

 

[Nigel Goodwin]

Re: circuit plzzzzz

i thank everyone who have posted but i need a circuit diagram on the topic if u guys cud help me i wud be happy!!!!
thanx,waiting for the circuit so that i can get into action!

You're not talking about a 'circuit', you're talking about a 'transducer', a device that converts mechanical energy into electrical energy. For a circuit all you need is a blocking diode to feed the battery.

There have been a number of suggestions of how it might be done, you need to experiment to try and find what might be practical - but essentially most of them consist of a coil and a moving magnet.

 

[chemelec]

Oznog: They're probably doing the same thing as the "shakelights". Induction coil and a cylindrical neodymium magnet that can slide back and forth through it.

Actually I bought one of those Shake lights, (With An LED Light) Just for Fun.

Being Curious, I Took it apart to find out there was NO MAGNET in it.
JUST A Plain, Short STEEL ROD.
And Just Two Small Batteries. The Coil did NOT Generate any power.
It Wasn't even Electrically Connected to the batterys
But thats somewhat understandable, because those batteries are Also NOT Rechargeable anyway.

After "Carefully Reading the Article" Supplied with it, It Didn't Actually say it Did generate power.
But it Sure Implied something to that effect.

I was NOT False Advertising, But REALLY DECEPTIVE WRITING.

 

[Nigel Goodwin]

Being Curious, I Took it apart to find out there was NO MAGNET in it.

You were ripped off, proper ones have a magnet and no batteries!.

 

[audioguru]

Remember long ago when the Japanese were learning electronics and made some very crude products? One product was stamped "Made in Usa". Usa was the name of a little town in Japan.

Some of their AM portable radios were embossed "14 transistors". Inside even the detector diode was a transistor and 7 transistors were neatly connected together in a circle and not connected to the circuit! :lol:

 

[chemelec]

Being Curious, I Took it apart to find out there was NO MAGNET in it.

You were ripped off, proper ones have a magnet and no batteries!.

If The Proper ones Don't have Batteries, They Definately need a Good, Very High Capacitance Capacitor to hold the Current Charge.

Either that or you would need to be Constantly Shaking It while your trying to point it.
Not Very Practical.

I Suggest you check out a Proper one and let us Know what it Actually Contains.

audioguru Posted: Remember long ago when the Japanese were learning electronics and made some very crude products? One product was stamped "Made in Usa". Usa was the name of a little town in Japan.

Some of their AM portable radios were embossed "14 transistors". Inside even the detector diode was a transistor and 7 transistors were neatly connected together in a circle and not connected to the circuit!

YES, I Remember those Very Well.

There is Also the Crappy Wattage Ratings on Power Amplifiers.
Also Speakers.

One VERY BIG Manufacturer who's name I won't mention here, Listed one of there Speaker to be rated at: 150 Watts, "RMS" and an 8 Ohm impedance.
Inside the cabinet was an inline 2 Amp, auto-reset Fuse.
**Try to Figure that one out?

 

[audioguru]

Getting my slide-rule for that one:
1) 2A RMS into 8 ohms is 32W RMS. The voice coil will heat quicker than the fuse so it becomes 10 ohms, and the power rating is 40W RMS.
2) Music that isn't compressed too much has an average to peak ratio of about 1:10, so the speaker could have a rating of 400W!

No, that's music power, it would have a rating of 800W max (for square-waves).
Let's see. At resonance, a speaker's impedance is much higher. It would be 37.5 ohms to carry 150W and the 2A fuse wouldn't blow.

See how a cheap little speaker (or amplifier) can be rated for 150 Whats? :lol:

 

[Nigel Goodwin]

If The Proper ones Don't have Batteries, They Definately need a Good, Very High Capacitance Capacitor to hold the Current Charge.

Either that or you would need to be Constantly Shaking It while your trying to point it.
Not Very Practical.

I Suggest you check out a Proper one and let us Know what it Actually Contains.

They contain a 'super cap', if you search back in these very forums there are a number of threads about them, including disassembled pictures of one.

 

[Oznog]

They contain a 'super cap', if you search back in these very forums there are a number of threads about them, including disassembled pictures of one.

Oh I'm laughing my ass off that they sold a regular flashlight with a fake shaker so users go shaking the thing around for no reason.
http://www.21st-century-goods.com/page/21st/PROD/WNGO
Not all of these contain a "super cap". The hand-crank dynamo LED flashlight I have had a rechargeable lithium coin cell inside.

Yep- rechargeable lithium coin. I looked up the part number, got the spec sheet, and everything.

chemelec, What's the Deal with the Random Punctuation? I can't even fit that into any mode of speech I've heard.

 

[audioguru]

I wonder how soon the gears strip on the crank.

Gary's punctuation is fine. He uses caPitalS SomeTimEs becauSe he doesn't want TO BE RUDE!

 

[chemelec]

No, that's music power.
See how a cheap little speaker (or amplifier) can be rated for 150 Whats? :lol:

I Agree it must be music power, But it was definately stated as RMS power.

 

[audioguru]

No, that's music power.
See how a cheap little speaker (or amplifier) can be rated for 150 Whats? :lol:

I Agree it must be music power, But it was definately stated as RMS power.

Didn't it say for what duration (milliseconds or tone bursts?)?
Didn't it say what frequency (high impedance resonance?)?
Didn't it say how much distortion (awful-sounding with its voice-coil jumping out of the magnetic gap, or hitting the ends of the magnetic structure?)?
Didn't you see the tiny decimal point so it reads 15.0W? :lol: :lol: