Wireless Power

Wireless Power
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.

200,000 views and more than 500 comments. Thanks for all your awesome feedback!


 
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Step 1What is it? How does it work?

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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649 comments
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Jan 3, 2012. 4:13 PMhrishikeshp says:
anyone know a function generator kit like the one mentioned above that is cheap, because the one oin his post is retired, and someone posted a newone, but it is also retired Please help!!!!
Jan 3, 2012. 2:56 PMHamayal says:
Hi Robotkid249, I had just finised reading your article on, Wireless Electricity, and it was very well written, and the eagar to see it for my self, I tried building the model explained, seeing the success before me. It's great to see some one who takes pleasure in expiressing their knowledge with others, such as yourself. I wasnted to implement this concept, into another situation, in which I would like to power a 9V motor DC motor. What guage of wire would I require in the primary and secondary coils to do make this work smoothly, and how would I, in the future, be able to determine this on my own? Thanks, Hamayal.
Jun 20, 2011. 4:41 AMNeMewSys says:
Hi, great article!!
Your 147.7 square wave AC signal generator just retired from the market, are there any alternatives?

How do you know wich capacitor to use to get that frequency? Could you show us the math?

Thanks ;)
Jun 20, 2011. 6:23 PMdanielkim802 says:
there's a newer version of the kit that can still produce the same output: http://www.sparkfun.com/products/10015
Jan 3, 2012. 6:26 AMbvd says:
I am also very interested in this.

Can someone point me in the direction of a kit I could use to generate the 149KHz signal?
Dec 23, 2011. 8:54 AMhrishikeshp says:
hey i checked that link and that one was retired too anybody have suggestions?
Jan 5, 2012. 9:07 PMShogunD says:
http://electronics-diy.com/store.php?sel=kits&sub=function_generator
Theres a possibility.
I haven't tried it yet but I plan on it.
Dec 20, 2011. 12:03 PMmirtunio says:
Hey I have a question, what are the cons if I use a 18 - 20Hz signal and what capacitance should I use on the receiver end?
Dec 27, 2011. 4:26 AMadilvij9 says:
Hi, we want do this project but the problem is we don't know

which type of copper wires to be used, ( i.e thickness of wire)

what are the dimensions to be used please tel the length and breath

1) primary coil dimensions

2) secondary dimensions

and last thing is "how/ can we glow the led about 10 inches from primary coil ".

please help .we really want to do this . please answer ...
Dec 5, 2011. 3:50 PMblob800 says:
Very nice instructable!

I'm interested in learning more about inductors, LC circuits, etc. Did you find any good books on these subjects? (where did you learn that you need a 147.7 kHz square wave AC signal)?
Aug 22, 2011. 9:57 AMM-Taimoor says:
I wanna know that which copper coils these are, are they insulated or wiring copper coils
Nov 16, 2011. 3:22 AMadas11 says:
i interested in this topic.i am an electrical engineering student. plzz any one send me perfect list of equipments my mail id is anjaliswann@gmail.com
Nov 24, 2011. 7:41 PMTheHomebrewGuru says:
MIT copied Nikola Tesla, big deal
Nov 23, 2011. 1:28 PMNeMewSys says:
Hi robotkid249, could you provide a more detailed schematic of the coil number one (the most complex), with the values and part names, like you did for the second one? Thanks! Great device :)
Nov 14, 2011. 1:55 AMDixonLam says:
Can i know the input voltage is 6volts in DC or AC??

I had run testing on this project topic also but i could not get a high output from the receiver part.
Nov 10, 2011. 4:51 PMrr5 says:
please help me..........can u tell how many turn in secondary coil ..? very urgent & want to prepare 4 exhibition
May 8, 2011. 9:57 AMjmg1271 says:
Tesla transmitted power wirelessly a century ago. Anyone ever heard of Colorado Springs? How about the tower he never finished in Shoreham, NY?
Jun 22, 2011. 5:29 AMR.A.T.M says:
ya but this it much diffrent and dont get me rong tesla is awsome almost a god to somepople but the pont being that this can be built by anyone with commonknolag o electronics
Sep 30, 2011. 5:51 AMvernors says:
(removed by author or community request)
Sep 30, 2011. 6:47 AMR.A.T.M says:
do you even know what jmg1271 is talking about
Aug 27, 2011. 8:56 PMmarkee2 says:
Nice instructables! got some problem in freq matching. Got similar idea of the project and gives some formula of the frequency you wish to use depending on the available capacitor , inductor, and supply frequency you have.
from:
 http://www.simple-electronics.com/2011/08/wireless-power-witricity-project.html

F1=F2= 1/(2π√(L2*C2))

resonant transmission.jpg
Aug 23, 2011. 4:30 PMwmiddleton says:
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?
Aug 11, 2011. 1:13 PMdlinvega says:
While I have no knowledge of electronics, this is a really good intensive to learn and so, I would like to figure it out and teach other beginners like me.

It would be really nice if you could begin the instructable with a list of items one will need.

Required:

- 1 x Function Generator kit [link]
- # x Capacit..
...
Alternatively you can by the kit [link]

Anywho, keep up the nice work!
Aug 10, 2011. 8:01 PMsteev2_hovey says:
It's wont open... could someone send me the PDF file please, steev2_hovey@hotmail.com
Aug 9, 2011. 4:14 AMjkline3 says:
Hi Can some please send me a exact list of componets and/or simpler instructions.

My email:
jacksen.kline@gmail.com
Jul 25, 2011. 6:20 AMTNThieding says:
I was very surprised I got this to work! Through the process of building, I was scared of power spreading all over and ruining electronic devices. In the end I was in awe!
Jul 7, 2011. 7:14 AMrohitforothers says:
heh can any1 send me the a perfect list of components required for it
on rohitforothers@gmail.com
The faster the list gets to me the better...
plz help on...
May 5, 2011. 1:19 PMMadScientist101 says:
could you use a 555ic to replace the function genorater?
May 15, 2011. 10:28 AMMadScientist101 says:
why, surely it would do the same job but less options
May 26, 2011. 2:10 PMGoodhart says:
LM555's are power hogs...really !
Jun 12, 2011. 7:14 PMThe nerdling says:
dang i have heaps
Jun 15, 2011. 2:05 PMGoodhart says:
Well, compared to their low powered cousins they are....still they are quite useful.....just not if you need to keep a battery fresh without recharge for awhile. I have a bunch of them too, as I use then for simple timing projects....
Jun 15, 2011. 4:37 PMThe nerdling says:
ok
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Author:robotkid249
"I am always doing that which I cannot do, in order that I may learn how to do it." -Pablo Picasso "Everyone can be smart. Everyone is given a box of crayons in Kindergarden." There are only two mis...
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