Re: Inexperienced and need to find/design 2ch remote control+audio receiver combo

Thank you, Frank, for your helpful post. This all just landed on me
the other day, and in addition to the technical matters with which I
have little experience, there are the even more daunting legal (FCC)
matters with which I am even less familiar. Obviously, no matter how
hard I study, there are limits to how much I can learn in a short time,
so any pre-processed input from someone who has experience is greatly
appreciated.

I *think* I may have found a way to get this project taken on by a
professional in this area. It's a tricky business. While Phil has hit
upon the "naivety' factor, he missed the "extremely limited resources"
part. Here's hoping.

In that case, all I would have to do is create a demo unit for
presentation that *does* what we need it to do. It wouldn't have to
have the range. It wouldn't have to operate at the frequencies that
the end product would. And would not have to have the security. It's
the difference between building something that 'works' and designing a
'product'. I feel well up to the former task. The latter scares the
hell out of me.

Anyway, I'm still very interested in coming up with the best solution I
can, if only to compare it to what actually gets designed assuming that
we can get this taken on.

To that end:

1. The target size is about 10x10x3 cm.

2. Battery life needs to be at least a few hours.

3. It needs to have a two channel remote control.

4. The first channel would power up a circuit that flashes a set of
LED's marquee style.

5. The second channel would operate a small buzzer motor.

6. Independently, monophonic voice quality audio would be transmitted
to the device. It would need to be loud
enough to be heard and understood by the wearer.

7. All devices would be performing these actions in unison.

8. The channel 1, channel 2 remotes, and the voice, may occur either
alone or in combination with each other.

9. All actions would be under manual control. But the operator would
be selecting combinations of actions from a menu in a browser based
application and executing them that way. He/she would not be pushing a
button on an appliance device like with a garage door opener. The
audio would be the output of a sound card in the server. It could be
reproducing either decoded mp3 or ogg files, or passing through real
time voice from the operator.

10. The transmission would be intermittent, not continuous.

11. It is understood that licensing for use of a higher power
transmitter and/or use of the particular frequencies used, may be
required.

12. I had been considering the possibility of using repeaters, but am
not sure what the legal requirements for that might be.


13. The thing about all of this that scares me the most is the security
issue. The fact that I need to operate all devices simultaneously, and
that the wearers would actually own the devices, taking them home with
them, plus the fact that these people are essentially anonymous, makes
it virtually impossible to secure this in such a way that someone could
not commandeer control of the devices for their own purposes, if even
in a limited area. This is particularly worrisome for the audio. The
"normal" methods of securing transmissions between pairs of
transmitters and receivers don't apply, here, so far as I can see.

In general, I would be interested in advice as to a general strategy to
pursue. There is obviously too much for me to learn in a short time.
So my current strategy is to find a direction that looks reasonable,
and focus my efforts on familiarizing myself with the specifics of
that. And, of course, seeing if I can get this project transfered to
people who know what they are doing. ;-)

Thanks again for your help,
Steve

.