Wireless Power

won't the magnetic field screw the memory of an mp3 player or something?

 If you have a hard drive in the MP3 player, then yes. Examples: Older iPod models like the iPod 1G, and one of the newer iPod models: iPod Classic (5G).
If you have flash memory, then no. Examples: Newer iPod models (excluding, of course the iPod 5G) and all iPhone models, as well as most other MP3 players.

You could always use a ferrite choke to cut down on the magnetic interference on the cord running to the MP3 player. (www.radioshack.com/product/index.jsp?productId=3012599)

And of course, you could just test it out and see what happens...

 So my c200 Sansa won't be affected by it?

Yours Sansa C200 will be safe seeing as it is a solid state memory device so you can use this tech. with out erasing your MP3.

awesome! I think I might make one of these then!

 um, whats the mathematic relation between the gauge of the wire, # of turns, size/shape of the coil, frequency and capacitance? or were I can find it?

Nice Instrutable! Very well done!

will this work like the power mat?

whats the voltage on your primary ?.....I want make a higher power one........I am thinking of using the electronic ballast of an flurosent tube....it is rated 40 watt and 56khz.....it also AC...so what do you think ?...will it work ??

The energy vampire thing is probably a bit overkill.

I think all you need is a step up transformer and a single diode and capacitor. The bead might be all you need to make the transformer if you wind it right; and if the load is the LED, you probably don't even need the diode, just a resistor to limit current.

If you do this though, you may need to up the frequency, the bead works best at high freq.

Um... my circuit is amplified (volt wise) when it passes through my glass of orange juice, i this normal? if yes what is amplifying it the plastic cup or the orange juice cuz i would like to know

So, what's the capacitor for? You said that it is necessary for magnetic resonance, but what does that mean?

Nice project, I have a computer mouse that works on this technology thus beeing wireless but having no bateries, I bought it like 5 years ago, it`s good to know how it works

Sorry to ask again but I'm having some some trouble with the 555 timer circuit. I'm using the astable 555 timer circuit but when I plug it into the coil the 555 timer gets really hot and the frequency goes way off (like it changes from 150 khz to 110 than back to 170 and then to 150 again). If anyone has any ideas please help me, and if anyone has any better ideas on how to make the 555 circuit can you please send it to samr37l@gmail.com. Thanks a lot,
SAm

The primary coil probably is drawing too much current for what the 555 can stably provide. It is a good idea to use a power transistor or something for the coil that way your don't draw your power from the 555 it's self.

Also, because of the heat the current is making the 555 will mess up. It does it with temperature drift.... that is why it's probably better to get a function generator that is more resistant to this. It is a common problem, does the same thing with cold too.

do you have a good circuit to do this? like how could a put in the power transistor cuz I already tried that and I blew a 555 timer.
Thanks,
Sam

It's probably a voltage thing.

The point of this system is that the sender coil has to ring strongly- you're probably overloading the 555 timer, because the volts on the ringing coil are tens of volts, in both directions, even though you're only feeding in a few volts from the oscillator. I doubt the 555 timer can take that. At the very least you need a transistor or two to decouple the timer from the coil.

I don't really have a circuit, but you just use it like any old transistor. A power transistor is rated for more current. Basically just hook up the output of the 555 to the base of your transistor, then have the coil power hooked up to the other two ends of the transistor. In this way the transistor acts like a switch and will pulse the coil on an off but the power transistor will take allow for more current to be drawn.

do the coils have to be uniform ?

Couldnt you use a crystal resonator on the secondary coil?

what is the power output on the secondary coil? could one use a 5v regulator to charge an ipod or is there not enough power. how does one adjust the power output of the function generator?

Wow, I always wanted to do something like this but never really understood how to. My dad had an old function generator, an oscilloscope, and this capacitive decade box thing. I used 0.022 uf because it was the closest value to yours. Then i hook up my scope and set it to graph volts and tweaked the frequency and it worked perfectly. Then i started playing with the amplitude settings and then i got some strange numbers. I got close to 45 volts ac when the coil was directly in the other one. I also checked the amperage and i was getting about 20 mah but i don't know how i was getting so much voltage. But great Instructable dude, 5 star.

Yes, it's a resonant circuit. You really can get stuff like that happening. It's like pushing a swing, you feed in a small amount of energy on each cycle and it gets bigger and bigger until the losses equal the energy you put in. These circuits are quite low percentage loss, so the voltage/current can go up many fold over what you feed in.

For the function generator you might be better off using a Colpitts oscillator, it can give quite a bit of power.

I'm also wondering a bit about your receiver circuit. Your circuit goes AC->DC which then feeds into the Joule thief which then goes DC->AC (at much the same frequency you started at) and then goes through the ferrite bead, which is essentially a step up transformer and then it gets rectified by the light-emitting diode again!!! It seems a bit tortuous.

I think you would do slightly better to wire the ferrite bead onto the receiver coil- you're already at high enough frequency for that to work I think (more or less anyway, you could up the system frequency to make absolutely sure if necessary) and then feed the output of that straight into your LED.

Also, the more turns on the ferrite on the LED side the better, you need the volts, particularly at long range.

how could i make this on a larger scale perhaps the main coil at 1 sq. ft.

Isnt yur cap a little counterproductive? Should it not be inline with the positive line, rather than spliced into both leads?

As someone else stated, the two capacitors are in series, so the actual value is .0.005 uF or 5 nF. This value across the coil creastes a parallel tuned tank circuit which resonates at some frequency determined by the coil inductance (the .005 uF is fixed). This inductance is determined by the number of turns you put on the coil. I would suggest varying the frequency to see where the best results are, since the author gave no specifics about how big the coil was and how many turns it had.

Also, the LED is a light emitting DIODE, and hence rectifies the AC like a diode. But it takes over 2 volts to light up a red LED, and even more for other colors. It might give better power transfer if more turns were added to the coil, and lower capacitance used.

Also, 1N5817 schottky rectifier and filter capacitor could be used to rectify the coil's AC to a DC, and then a voltage boost circuit such as a Joule Thief could be used to extract even more power out of the coil. But the real problem is that the output of the function generator is very low. In the schematic of the function generator, they show that only one of the 'HC04 inverters is used, the other four are not used. I ordered one, and the first thing I'm going to do is cut the circuit board traces and add the other four inverters in parallel with the output. That will give a lot more output current.

Another thought. The function generator could be replaced with a simple Joule Thief circuit. The big coil would be the main JT coil, and another coil would be added for the feedback coil. Once the JT 'transmitter' is working, the receiving coil would be tuned to the transmitter's frequency. JTs work around this frequency, in the 50 to 200 kHz range.

The radio snack wire that you gave has three sizes of wire. The above says 'your magnet wire' but not which size you used. Please add. Thanks.

I would like to build the circuit by sparkfun by myself, i bought the components from a local electronics store but i have trouble reading the circuit, for example there are many 74hc04n ICs displaye in the circuit yet only one is needed and the 74hc04 IC has 16 pins but only one input and output is stated in the diagram so how do i connect this?

sorry, probably a little off topic but i have some comments about this project
1. Amazing, thank you. I needed a high voltage out for a few ion experiments i want to do. I am also wondering if this can be done strictly through vaccume tubes (modified or otherwise, i have a few compressors (one from canadian tire, and one from an old freezer) i'm still looking into whether this is enough vaccume pressure to operate thermionic tubes.

2. Nikola Tesla did NOT "invent" AC or DC. Many professors and students of the art at the time postulated on AC type movement and DC type movement. Long before Tesla arrived on the scene. DC was what more research had been done (probably cause no one wanted to do higher calculus). Through solving the math equations in 4 dimentions(xyz, and time) Tesla found a better description of atomic/ionic interactions through electric and magnetic fields. Infact he was able to utilize the vanderwaals forces in ways that even we havent tried properly (many people think HAARP but most situations and installations do not follow the principles outlined by tesla. Tesla found in AC, the components and infrastructure (that he invented or adapted from other inventors in europe at the time) would allow for a power grid. In Electrostatics (a more general form of DC found everywhere in nature) tesla found the movement of colombs can be more economical (i wont dicuss the mechanism here cause i feel its a right of passage reading his lectures to understand the ramification of this mode of energy. War would have to end or we would perish.. kinda like nukes).

dick tracy said "he who controls magnatism controlls the world" what he didnt know was tesla had mastered the magnetic field and saw that electrostatic ion reactions controlled the universe. He didnt agree with two modern viewpoints. 1, einstein was taken advantage of; too many assumptions taken (einstein left out the electric universe!) 2, particles. When wave interactions can create particle behaviors he still understood that matter is a wave matrix. i could go on but no one has the attention span for true electrical theory any more, let alone any of tesla's lectures.

Your compressors won't achieve anywhere near the level of vacuum that you need to operate any sort of "vacuum tube". In fact, the level of vacuum will be so low that anything you would attempt would be considered "gas-filled". You need s very powerful vacuum pump, such as an oil diffusion pump, to build a vacuum tube.

this is very true, i've recently come across better data on the requirements. Though i've now thought about creating a partial vaccume with a conductive gas like oxygen and no wire inside the bulb. You could use a bifilar pancake coil (with magnetic fields reinforcing rather than cancelling) to acellerate the gas by a capacitance effect. Im not sure that it would be a more efficient way to light things though.

"Once i did it I found that you do not need to go to MIT do do this sort of stuff." While you're right about that, this doesn't compare to what they did. The device that you demonstrate here has been around for many decades. It is commonly used in devices such as wireless mice that don't use batteries.

how did connecting a capacitor makes the coil coupled???

I am completely confused at what you mean about making either of the coils. Can you go into more details? I am kind've short on budget and can't afford to make several and test them.

Magnet wire is used in many types of transformers so can be stripped from old equipment and i beleive that old microwave ovens are cheap sources of magnet wire (coated in insulating material so that when 'coils' are made they don't just short circuit)

I am not sure how to make the coils, it wasn't very descriptive. Also i am not sure how to set up the function generator kit

you stick four nails in a board and wrap it around, over and over until it's the right size. then you pull some out and lift the coil off. wrap a bit of tape around each side and you're good to go!

Would a primary coil and the receiver coil having similar loop size increase the efficiency of the power transfer? Since maximum efficiency would require the receiver loop to be in the center of the primary coil, that seems to make sense. Any ideas?

I highly suggest you read up on MIT's recreation of Nikola Tesla's experiment (though modern society is so historically dense that they gave MIT the applause that had been waiting tesla for about 100 years now).

What you want to do is calculate the capacitance and inductance of the sending and recieving circuits. You want the circuits to be in "Resonance"

Here are two MIT Lectures that deal with this idea.
-The first link is on Resonance.
http://www.youtube.com/watch?v=eqjl-qRy71w
- The second link is on non conservative fields (the recieving circuit and how power is distributed with in such a circuit). VERY NON INTUITIVE!]

I highly suggest for anyone studying electricity to review Walter Lewins lectures on physics. He allways had an experiment of some kind to show you a physical representation of the theory, he does not leave holes in the explination, and he will admit faults in the theory. He does not assume you are stupid and "just dont understand" like most teachers i've come into contact with.

Hey your LED is in parallel to your circuit, in fact if you set it up that way you don't really even need the capacitors. I am beginning to question whether you are using a resonant coil; you said you used .02 uF but your capacitors are in series making the capacitance .005 uF. What I see here is either a simple air core transformer, or an extremely lucky resonant coil. I suggest you try and measure your inductance and then calculate and see if you are making a resonant circuit. Could you post some dimensions for your coils? and what gauge you used?

Thanks, and nice job!
Dr. Choc

guys u shold know that this is nothing new little more over 100 years ago a serbian scientist doctor Nikola Tesla invented wireless power transmission and the electricity could go over few miles
- and yes he is the one that invented tesla turbine , dc motor and dc electricity and many other important thinghs we use in our daily lives.

Tesla invented AC and the AC motor, not DC. Tesla viewed DC as inefficient and wasteful, and eventually faced off against his original employer (Thomas Edison) to determine which system of current delivery would become the standard for consumer use. Tesla did do some groundbreaking work with electricity, if anyone's interested in wireless power, his old projects are worth looking into. He was decades before his time.

Tesla invented AC power

did any one tried calc the input power and output power of the ckt??

what is the efficiency wid ur ckts??

and value of capacitance used is 0.005uF not 0..02uF.

and it'll work not only wid square but also wid sine and tringular waves.

did any one notice?? what ever may be the input wave , output at sec coil is always sine. I figured it out why it happens.....is any one else interested??