# Wireless Power

Quarter of a million views, thanks everyone!

The power cord, I know you hate it. Sometimes, you just want to cut it apart! Well say goodbye to your power cords, because with the power of inductive coupling your device will not need to be connected metal to metal. Seemlessly your device can be charged!

This instructable will show you the basics of creating your own cheap and easy wireless power mat, which you can use to power your device through the air!

New Update: complete list of components.

Check out my new project on sending a balloon into space!!
http://www.instructables.com/id/My-Space-Balloon-Project-Stratohab-Success-High/

## Step 1: What is it? How does it work?

A few years ago MIT created a system for transferring power wirelessly. They transmitted power over a two-meter distance, from the coil on the left to the coil on the right, where it powers a 60W light bulb. Back in 2006, this was a pretty cool thing. You can only imagine what the implications of something like this would be. Well, unlike most of us, we do not have the time or material goods like MIT has. So i have made this simple and easy to follow Instructable, so all of you good people can experience the joy of wireless power.

Inductive Coupling uses magnetic fields to transfer power. There is a primary coil, which generates a magnetic field. Then there is another secondary coil which is composed of a capacitor and a coil, the capacitor creates a resonant circuit with the primary and secondary coils. Seem easy? Well, before publishing this instructable I found many useful and a lot of non-useful info on the subject.

In my research I found, that to transfer power in very complicated. Once i did it I found that you do not need to go to MIT do do this sort of stuff. With a little electrical know how, this is easy.

It all starts with the transmitter. This transmitter needs to create 147.7 kHz square wave AC signal. Let me take a minute to explain this all. Level one on the frequency scale is Hertzs, then there is kHz, then MHz. MIT used a 10 mHz wave to drive there coils, but for this we will be using a 147.7 kHz signal so it does not get too complicated.

The secondary coil has a 0.02 uF capacitor. This will allow the two circuits to be coupled therefore, transferring power efficiently. The 0.02 uF capacitor is used only for this frequency, and the value of this capcitor will change depending on the frequency.

The primary coil creates a magnetic field, when another coil is placed near it, energy will be induced into it.

Be in mind that i could not get a hold of a 0.02uF capacitor so i used two 0.01uF capacitors connected together.

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danzman1 month ago

What do you think of this circuit - https://www.youtube.com/watch?v=4UmVLfFNx7U . I think this is the simplest and cheapest system I have seen. Can this work with your primary coil?

rikkebobbie0072 months ago
can you get ahold of a hertz-uF ratio for me. I would like to tamper with this concept if you don't mind.
Elecstudent4 months ago
Would someone please provide a better schematic? I'm not sure if I'm building this wrong, but mine is not working, I did a lot of troubleshooting and etc but unsuccessful.. Any help would be appreciated..
PolaR14 months ago
i love this
ChemTrailsMN.4 months ago

Has anyone built a WIFI Power Harvesting circuit that will power an LED as yet? If So please let me know the scematic, thanks.

marlon.bell.57 months ago

MIT did't invent this its like 100 years old

5 months ago

damn right they dint invent this, it was Nikola Tesla, how can MIT claim to invent a device that was created 100 or so years earlier, Teslas main coil that would of supplied the world with free wireless energy was dismantled and sent to a dark room in A51, MIT are wrong to claim they invented this when they obviously didnt.....poor tesla ripped off by everyone he worked with including Thomas Edison, and Einstein, and now he's been ripped off again by a school

7 months ago
Nicola tesla
Can i use wifi or bluetooth emission to power a led, if so could you explain...
gxb54436 years ago
Do the inductances have to match between the two coils have to be the same?
6 months ago

Yes

6 years ago
no, however the number of coils on both sides along with the distance between them (called the mutually inducive element) and the load you use will affect the applied emf to the secondary circuit.
6 years ago
oh so this will transfer power no matter what. If the the base and reciever were tuned to one another though there would be way greater efficiency, right?
6 years ago
If the Circuit reached resonance, there would be voltage/current magnification, which you may have to consider when choosing your components. the advantage would be that energy would only be dispersed A, in the resistive element, and in the space between the coils. i looked it up, and every time the distance doubles, you lose magnetic power by a factor of 4.
6 years ago
the load will have effect? How do you take that into account? So this way is just two arbitrary coils that will couple together. If you tuned the base and receiver to be in resonance, wouldn't that transfer as close to 100% power transfer as you can get?
here two capacitor of value .01 uf are connected in parallel or series???????
6 months ago

parallel

4 years ago
Parallel.
quinnmiller19977 months ago
This is an amazing guide! Very informative. Thank you
evictor21 year ago

Aren't the exposed wires dangerous because AC is passing through them? How can this be insulated safely without affecting the resonant properties of transmitting and receiving coils?

7 months ago
Looks like low voltage to me
1 year ago

The power is so low that it won't hurt you.

1 year ago
Thanks for the reply. Would that still be the case if I were to build a unit capable of powering a 40W 120V light bulb wirelessly? Would the conductive socket of the bulb and other exposed wires need to be insulated then?
AliganyiraT7 months ago

Well done but my main target is " Transfer of electricity " completely without any single wire. As we join hands in that research, we should also focus our aims at long distance applications. Let's connect at, aliganyirataddeo2014@gmail.com.

john.hawes.969 months ago

I see a heck of a lot of wire for something supposedly 'wireless' .

8 months ago
wireless as in you are not physically hooking your device to a power source other than putting the receiver on it. make the receiver penang and you have wireless power.

could you tell us the formulas required to calculate the values to prepare the primary and secondary coils and also the ratings of the components used to construct the required circuit to achieve the specific output(i.e voltage and amperes).

railgunfuzz5 years ago
Couldnt you use a crystal resonator on the secondary coil?
10 months ago

Over doing it! Quartz resonators are in the kilohertz range.

06-04895 years ago
can the range be increased?....how?...is it posible to increase it to about 1meter or longer?.
5 years ago
yes the higher the frequency the longer the range
10 months ago

Also, the thinner the effective cross section of the wire, do not go overboard or your skin effect will fry your wire.

Websteria4 years ago
Is there a way to do this with a smaller amount of coil?
10 months ago

Yes, it can be accomplished in the same manner by using the same ratio of wraps of wire (internal coil/external coil) (make sure it is insulated wire and away from anything flammable as sparks may still ensue (and DO NOT plug a circuit like this into a wall or anything above a 1.5v battery))

wmiddleton4 years ago
hi, i'm liking this small DIY project :)
umm, what do i need to put in my mobile phone, mp3 etc. to charge it from the coils?
10 months ago

You should be able to find the information by removing the back panel of your cell phone and observing the sticker on the battery, it should say something like "6.5v 600mWh" the second number is how much your battery stores, the first is the voltage it stores at. Though, you shouldn't really try to charge your phone in that manner, you will end up frying your circuit board and possibly over charging your battery (not fun, lithium burns require hospital treatment.)

3 years ago
hello wmiddleton!!!
are you found the solution in your case???
i hope u can share u solution to me...
thank you...
MasoodZ10 months ago

Great,

wonder if I could make one too

MayankD10 months ago