Contactless Electrical Current Transfer?

ferralis (Not an EE) asks: "Recently I've come up with a design for a very fun toy (to be unveiled later if I'm successful). What's missing is a means to send electrical power over a distance of five to ten centimeters (2-4 inches). I've done some research (mostly online) and have found extremely limited information. Even my beloved Google has forsaken me, and even my pleadings to eldritch information deities such as AltaVista have gone unrewarded. Can anyone help?" "The way I see it, to do this a person needs merely set up a high-frequency electrical field using a larger coil (primary) and a similar but smaller coil (secondary) can be placed within it, creating an air-core transformer. Unfortunately I can't find the math or even anecdotes about what happens when the secondary is off-center, or there is more than one secondary introduced... and I am not looking to build a Tesla coil here. I can imagine that many toys could be built using such a system, and one would think the knowledge would be well known and readily available, but apparently it is not. For this application, efficiency is -not- an issue."

Comments

A question

[DAldredge]

Does the person using this toy have to live past the first use? :->

I've thought of this before too

[Toxygen]

A wireless power cord.

I mean, we've got wireless everything already, and all those radio waves and GHz signals are basically a form of energy streaming through the air, so why couldn't we do it with electricity?

Think of the bliss a wireless power bar would bring.

Patent pending.

Re:I've thought of this before too

[Anonymous Coward]

Think of the bliss a wireless power bar would bring.

Eternal bliss, as you step between it and your home network and wind up arcing 110 volts.

Well maybe not eternal bliss, if you have the evil bit set.

easy

[pizza_milkshake]

use lightning. i've seen it travel much further than you require.

One solution...

[wronskyMan]

You could mix up some chemicals, use your electric power source to put some current into them to cause a complex electrochemical reaction. Call this wireless energy reaction "charging", for example. Then when you want to power your toy, just put the chemicals into a sealed metal container in the toy (such as a "cell"). If you need more power, you could even use a group or "battery" of these "cells" to increase the voltage available to your toy. Then when you need more power, simply remove the chemical containers from the toy, "charge" them again, and put them back in.

Re:One solution...

[Henry V .009]

Oh come on, at least try a suggestion that could be accomplished with current technology. Your fancy schemes are obviously science fiction.

Well...

[Chilles]

A piece of copper wire of about 10 cm should do the trick.

Re:FCC Class B certification

[aminorex]

Built a little catapult that is wound back by a stepper, and tosses a metal ball into a catcher.
The catcher runs a generator. Now all you need is
an infinite supply of metal balls.

Okay, no metals balls? Use one of atmospheric gas
molecules, alpha particles, or photons.

(1) Atmospheric gases: Use a motor on the power
source to drive a fan. Use a fan on the power sink
to drive a generator.

(2) Alpha particles: Nevermind. This is a non-starter unless you can do thermionic power.

(3) Photons laser on the power source, PV on the
power sink.

Do you mind if things get wet?

[ankhank]

Squirt a stream of water across the four inch gap, aimed at a small Pelton wheel spinning a generator on the receiving end.