#How to make wireless spy earpiece for your exams

In this note we will learn about how to make your own wireless earpiece at home easily. 

But firstly we should learn how speaker works.

You can see the gif (animation) showing how speaker works.
As we know that when we apply voltage in the inductor, the inductor acts like a magnet this effect is known as electromagnet and we all know that in every magnet there are two poles(the south and north pole). Continues changing of poles in the speaker produces sound because like poles repel and unlike poles attract. You can see in the picture down below:

Because of this effect our speaker produces sound.

OK, I hope you have got internal working information of speaker.
But till now you only learned about speaker I will tell you more than this.

I will tell you one great fact i.e. as you can see the working picture of speaker you might have notice that why the inductor only moving up and down, why not the permanent magnet ?
This is because the permanent magnet is fixed in one place but if we fix inductor in one place and make the permanent magnet free then permanent magnet will move up and down same like an inductor by knowing this effect i design one circuit which works very well.

Circuit diagram of  wireless spy earpiece.

Circuit is very simple. You can see that there is an amplifier circuitry but instead of speaker I just use induction loop which acts like electromagnet and of-curse there should be the receiver in our ear. So, I just used neodymium magnet in my ear for the purpose of receiving the signal transmitted by induction loop. I found neodymium magnet near the laser from my old DVD player.

 Now, question is that how we get sound in our ear ?  The answer is that: Normally we get sound in our ear due to the vibration and that vibration can be achieve by the magnet which is in our ear. Now, again one more question occurs that is "How magnet vibrate ?" The answer is: Magnet vibrate because of electromagnetic effect I already sayed that if inductor in a speaker is placed at the fixed point then magnet vibrate same like a inductor.

So, in this task practically inductor is fixed in our neck and magnet is in our ear which can move freely also.

Hence, if we input any music or sound in the LM386 amplifier then it  amplifies the input signal and make it more powerful and sends the signals to the inductor loop which is placed inside your neck and due to the electromagnetic effect magnet vibrate and we can hear the sound easily.
You can see in the picture below:—

If you want to cheat more perfectly then better to tear down your mobile and just solder the long wire between the front camera and the mother board. And you can show all thing at real time using video chat. You can see the picture below:—