Help needed to construct wireless headphones

[Gaurav]

Hi everybody,
It has been a long time since my college and I wish to brush up my
learning that I once did. I am in need of a wireless headphone and
would love to construct one of my own. I understand that the basic
concept is that I channel the output of my music system to a FM
transmitter and receive it in a small FM receiver that I can carry
around in my pocket and listen to through headphones.

If I am right so far, it boils down to constructing a FM transmitter.
I came across some circuits, the easiest of which appeared to use
BA1404 chip. Unfortunately, I could not find the chip. I came across
some other simple digital circuits that used a set of NAND gates but I
could not get it to work. It appears that a breadboard (of the type I
am using to set my components on) is not suitaded for such fast
circuits. Could anyone please me point to a simple circuit which:

1. does not use too many components,
2. works with stereo transmission (what is music without stereo,
right?)
3. is easy to construct,
4. works on less power (cuz I do not need to transmit beyond maybe 50
feet), and most importantly
5. is hard to go wrong with.

I would be very thankful for your kind help in regaining my lost love
of electronics.

Cheers
Gaurav

 

[Michael Black]

On Mon, 5 May 2008, Gaurav wrote:

Hi everybody,
It has been a long time since my college and I wish to brush up my
learning that I once did. I am in need of a wireless headphone and
would love to construct one of my own. I understand that the basic
concept is that I channel the output of my music system to a FM
transmitter and receive it in a small FM receiver that I can carry
around in my pocket and listen to through headphones.

No, you're assuming the only way to do it is with radio. Right now you

will see really cheap wireless headphones that amount to nothing more
than an fm broadcast receiver in the headphones and a transmitter to
match, but that doesn't mean it's the best route.

Using IR (infrared) to transmit the sound may be better, and is hardly
a new idea. They existed thirty years ago.

Feed the audio into a voltage controlled oscillator running at some
frequency above audio, and that feeds a string of IR LEDs. Then at
the receiver, a photodiode or something to collect the IR light, and
then a demodulator to turn it back into audio. No fussing with radio.

Michael

 

[Gaurav]

Using IR (infrared) to transmit the sound may be better, and is hardly
a new idea.  They existed thirty years ago.
   Michael

Interesting idea indeed. But would that not mean that I would have to
remain in the line of sight with the emitters? Anyway, if it is easier
to construct, I am all for it. Could you please point me to some link
that does something of the kind. I will also google it up and see.

Thanks again.

Gaurav
PS: I guess, this will be a great learning experience. I would love to
hear more and more ideas.