On Thursday 06 February 2003 08:43 pm, you wrote:
> I recently aquired a Heavy Armor (www.armorbyotter.com) case for my
> PDA. It is a waterproof, crushproof, airtight case that still allows
> use of the PDA. It's really fantastic, it's even large enough for me
> to leave my compact flash 802.11 card in the unit, so I can use
> wireless while still environmentally protected. Sweet. However, there
> is one downside. When I wish to listen to some MP3s, I have to take
> the unit out of the case. So, I was trying to think of a way to get
> stereo audio out of the case without completely compromising the
> integrity of the case. Here are a few of my ideas:

> 1) Mechanical - If I could come up with a watertight connector, that
> might be an option. A watertight 1/8" stereo jack would be really
> cool, but I don't know if such a beast exists. Anyone seen anything
> relatively small (ie not mains plug sized) like this?

Hard to guarantee no leaks on any "normal" audio jack.  Maybe a bnc or=20
tnc connector would work better.

> 2) Optical - The bottom of the case is clear, so I was thinking about
> multiplexing the stereo signal into one stream and transmitting it
> optically through the case. This could work. I would have to make the
> internal portion of the circuit rather power efficient because I
> can't put D cells in there to power it. I was thinking of
> multiplexing into one signal because I was worried that if I
> transmitted two signals, I'd get some interchannel interference as
> the light travels within the polycarbonate.

This should be workable, but probably not without issues outdoors.

> 3) RF - This shouldn't be too hard. There must be thousands of little
> FM transmitters online. I would get one of those small cheap autoscan
> radios to receive the signal. Again, I don't know how power efficient
> those little transmitters are.

> 4) Induction - This one is perhaps a bit more wacky. I was thinking
> that with a couple of coils on the inside, and two more on the
> outside, I could pass the audio inductively between the two. Is this
> even feasible?

Absolutely, this could work.

> An ideal solution would be bluetooth of course. Though I have yet to
> see a bluetooth stereo headphone, and no doubt it would be out of my
> price range. If only there was an 802.11 headset :)
>
> Ideas, suggestions, threats, all welcome :)

I saw a really cool star trek looking earpiece complete with a short=20
microphone for cell phones that (apparantly) used bluetooth.  Just=20
caught the tail end of the review, but the reviewer really liked it,=20
that's for sure.

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