Make Your Own Invisible Earphones (including step by step video)

The video step by step tutorial

It is better to watch this video in HD formats.






How to use this invisible earphones?
        First you need to put a tiny magnet in one of  your ears or put two in both of  your ears. Then you need to wear a coil necklace which is connected with an amplifier. Next connect your mp3 player to the amplifier.  Cover the coil necklace and the amplifier properly with your clothes.Turn it on. Now you can enjoy music without being noticed by other people. You can use another small magnet to get it out.  This sort of Invisible headphones is sold on ebay.


 Warning
 Warning
(Warning : Don't put the magnet deeply in your ear. Although there is no medical proof that says magnets will cause trouble to your ear , it's better not to use this device for a long time. Magnetic fields can disrupt the operation of some internal medical devices such as pacemakers.Neodymium magnets are made with special powders and coatings, so they are very fragile. They are often plated with a metal such as nickel. The magnets can fracture at temperatures over 150 °C, or under impact as a result of their own acceleration. When this happens, in some cases the magnets may break apart so suddenly that flying pieces can cause injury.
Make sure that there are no magnets around you, when you use this device. These magnets can move with surprising force when exposed to another magnet or magnetic field.)



If you don't know what you can do with this device. please watch this video. (Just for Fun

Step 1: How invisible earphones work

As you know, in a normal speaker. The magnet stays still.  The coil vibrates producing sound. Unlike the normal speaker, when this device is working , the coil necklace which is around your neck stays still.  The magnet vibrates in your ear producing sound. 

Comments

[Frank_GuYun]

Well, this is not my original idea. I saw pictures of this sort device on ebay. Then I made a prototype. And it works. You can search the keyword
Invisible headphones or invisible earphone on ebay. There are two types of invisible headphones. I made the cheaper version which use a magnet as the
in-ear piece.

[Spikin66]

I have made it and it work very well thantks to you ! i have the LM386-1 and only 3 accus of 1,5V !! i have put the tiny magnet in plasticine.

[puyol15]

Hello possible question please I want to know how many Voltage In this Capacitor 220uF ?

[amahbouli]

what kin of wires connected between the coil necklace and the amplifier

[sandy7com]

i wanna run that device at-least 3 hour
how can that possible ?

[seductive_lamp]

would this work without an amp?

[haniups]

please tell me this device can work how long time?

[Frank_GuYun]

In the experiment , I use two Mitsubishi 9v batteries . It lasted about half an hour. I don't think we can use this sort of device for a long. Because it may do harm to your ear in the long run. This is for your Mission impossible. LOL

[makecircuit]

please frank watch my website about this projet

dobyself.blogspot.com

[amahbouli]

Hi . Thank you for sharing this !! and i realy have a problem with connecting The coil necklace with the ampli circuit can you help me with that ( just some hints )

[makecircuit]

you find more information here

dobyself.blogspot.com

[makecircuit]

i love this website i learn lot of information from here thank you all thank you so match
i have some information about invisible headphone here join us

dobyself. blogspot . com

[amahbouli]

can i use the LM358 for it ?

[amahbouli]

Hi . Thank you for sharing this !! and i realy have a problem with connecting The coil necklace with the ampli necklace can you help me with that ( just some hints )

[neoygeo666]

great instructable ill try it just one queestion... while more turns give around the coil more impedance? jeje sory but im not that much familiar with electronics and more ohms more power to the magnetic field?

[Frank_GuYun]

You are right. More turns do give around the coil more impedance . But the increase in impedance is not the major influence in this case.

[thegreatestpenn]

I have a quick question about the powering of the device. Is it possible to knock down the operating voltage by switching to a different LM386 Amp?

[Frank_GuYun]

The higher the input voltage , the higher output power you'll get .So If you lower the voltage and the correspond decrease in sound volume is acceptable , you can choose using other kinds of battery. But I do recommend you to use two 9v batteries at first.

[smorton2]

so i made one using a different audio amplifier its not very loud. do yo uthink that its could be my coil or that my amp is not strong enough?

[yousra]

plz sir frank how to use this if i put the microphone when i use a telefone help me plzz

we ned your help use this like in telefone not mp3 ok i waitt you

send me a circuit plz when i put a microphone in circuit and wht the audio jack to usee

plz help me

[yousra]

plz sir frank how to use this if i put the microphone when i use a telefone help me plzz

we ned your help use this like in telefone not mp3 ok i waitt you

send me a circuit plz when i put a microphone in circuit and wht the audio jack to usee

plz help me

[yousra]

plz sir frank how to use this if i put the microphone when i use a telefone help me plzz

we ned your help use this like in telefone not mp3 ok i waitt you

send me a circuit plz when i put a microphone in circuit and wht the audio jack to usee

plz help me

[yousra]

plzzzzz help me frank how to augment volume of this invisible earphones if i augment twist 100 i can hear very strong or wht help me ;) excuse me my englich very baddd

[yousra]

To the people that say that the magnetic fielddof this device its serious Nicolo them what
For the regular speakers not so serious is the magnetic fielddd

[babylonx]

Hello, thats a great instructable!

I wonder, is there any other amplifier that can use less power and maybe only one 9V battery and last longer?

30 minutes on 2x9V batteries doesn't sound very promising.

Alternatively, is there any other way to save some battery life? I guess we need to decrease the output volume but even that would be ok for spying purposes I guess...

Thank you!

[SiesmicShockwaves]

I've built this and it worked great. I used an amplifier built into my boom box. What i want to know is how i can beef this up and make this into a sort of headphone interceptor. I want to increase the range potency and mess with people in public that are listening to music. I would mount the assembly in a bookbag. How can i beef this up like 4 or 5x?

Increase the length of the coils? Increase the voltage? Use a store bought driver?

Gvie me some pointers. Thanks!

[tomjoe77]

If I were to take this kit https://www.jameco.com/Jameco/Products/ProdDS/151204.PDF
and solder the coil necklace where the speaker should go, and then solder the input cord where the microphone should be, would it be similar to your design?
Or would it even work at all?

[Frank_GuYun]

Your idea is right. The only problem is that this circuit includes an additional operational amplifier LM1458 to amplify the small signal from the microphone.

You can watch this amazing 5 minutes video to know more about op-amp.
http://www.youtube.com/watch?v=TQB1VlLBgJE

[Frank_GuYun]

The output signal from a mp3 player is much stronger than the output signal from a normal microphone. So a LM1458 is used to pre amplify the signal from the microphone.

[inventor matt]

do all grounds or - connect together on schematic? im kinda new to circuits

where do audio ground go?

[Frank_GuYun]

Yes,all the ground wires are connected together. And in this project , the ground is connected to the negative of the battery. If you don't want to stick with the circuit, you can buy a amplifier. And I can I help you to find a proper one from the sellers you choose. Send me a message , if you need

[inventor matt]

also im using 31gauge magnet wire should that work it is .26mm

also its a LM386n-4 amplifier chip its 18v range ebay 10x = $4

selling these at school got huge list to buy but making $100's

[Frank_GuYun]

Sorry , I googled 31 gauge magnet wire. But I still don't know the parameters of 31gauge wire. If the diameter of the wire is 0.26mm. I think it would work.

[supaaben]

Ok here is my components list:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=113793278&uq=634709191197358557
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=113793296&uq=634709191197358557
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=113793477&uq=634709191197358557
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=113793547&uq=634709191197358557
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=113793603&uq=634709191197358557
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=113793635&uq=634709191197358557
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=113793667&uq=634709191197358557

What is that thing you used for the LM386 to plug into the board?

Where is the best place to buy that wire?

[supaaben]

And these too:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=113794015&uq=634709198822605915
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=113794147&uq=634709198822605915
2x http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=113794165&uq=634709198822605915

[salexandridis]

How many turns should the coil be?

[ljfa321]

Got it working, here is a video of mine working on a speaker instead of a coil, but its the same concept anyway.

http://youtu.be/kEocOJze5GI

[ljfa321]

Hi, for some reason mine is not working.
Checked everything but cant find the problem.
Can you check how many V the coil suppose to receive?
My coil didn't seen to get any voltage input after the 220uF cap, but the cap is getting around 6 V.

THanks

[Frank_GuYun]

You can connect the amplifier circuit to a normal speaker to conduct a test. If you couldn't hear sound from the normal speaker, there might be some problem with the circuit you built. If you still can't find the problem and you want to stick with the circuit, you can buy a amplifier. And I can I help you to find a proper one from the seller you choose. Send me a message , if you need

[ljfa321]

got it working, turn out its just my coil is too big and my magnet is not close enough to the coil. Will post the video later