I wanted to ask how can I built a covert micro earpiece. I think the design is quite simple, but Im not getting any thing related to making a spy earpiece. Help would be appreciated.
Thank you.
You mean a directional microphone and earphone that are small enough to clip onto your ear? Is that possible?
Or do you just mean like a hearing aid?
Either way, I'm not a hobbiest sure you can make one packaged well enough for you to use. You could certainly make a handheld thing that does the same thing though.
The source could be an mp3 player or a mobile phone. The earpiece should be small enough that it is not visible to others anyways and ofcourse should be wireless the distance between the earpiece and the induction loop can be small enough say around 15-30 cms. To give you an idea check out this page..
The expensive Chinese "invisible earphone" has a range of only 15cm. From the loop around your neck to the earphone in your ear.
There is no microphone, it receives audio from a cell phone.
start with a very small speaker-earpiece then add a battery and receiving circuit. The receiver is probably an AM detector with a reasonably high frequency >1MHz