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sonic ear or the like??

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New Member
Hey everyone! I want to build my own sonic ear or some sort of listening device but I am having trouble finding a plan for one. Does anyone have one or know what I need to do to build this thing? ANy help would be greatly appreciated! Thanks a lot.


Active Member
Hi phishinalong,

The principles are pretty standard for directional mikes.
If its for higher frequencies such as birdsong
then the cardboard centre of a toilet roll might do ok,
If its more for conversation filtering,
like picking out people from a crowd,
you would need a longer, and maybe wider tube,
to pick out from the surroundings.

You can follow speech with just the higher frequencies,
but it takes practice, and it sounds awful.

This kind of unit depends more on physical construction
than electronics, unless there have been some curious
advances made in this field that i dont know about.

I did hear about an evesdropping device that used a laser
which was modulated, and could be beamed through a
window into a room then shone on a surface such as a
picture, or thin item that would be expected to respond
to sounds in the room,

Then also a laser sensitive unit would be focussed on
that place, and the variations of its pick-up from
the modulated laser would be reproduced as sounds from
within the room.

This unit was alleged to give legible conversations
from up to a half a mile through the window of a room.

I have never seen such a device, but i was told they
are commonly known in circles that use them.

As to directional microphones,
thats more a constructional project
than electronic.

Best of luck with it,


Active Member
Hi phishinalong,

Maybe the centre of a kitchen roll of foil
would do, its a bit longer than a toilet roll

See what others say, there might be more
ways to do this than i know about.



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