Re: Bluetooth Microphone?
- From: Tim Newport-Peace <tnp@[127.0.0.1]>
- Date: Sun, 28 Oct 2007 00:29:23 +0100
X-no-archive: yes
In article <1193523482.744838.308560@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
SoaringXCellence <cirruscfi@xxxxxxxxx> writes
On Oct 27, 2:51 pm, Gary Emerson <emerson_g...@xxxxxxxxxxxxx> wrote:
Just curious if anyone is making a viable bluetooth microphone or
perhaps a bluetooth headset that is compatible with our typical aviation
radios.
Obviously glider pilots really only need the microphone, but since it's
a small market one might have to live with the headset.
A bit of googling didn't have anything jumping right out at me.
I'll jump in here and If I make too many mistakes I'm sure someone
else will jump in.
The Bluetooth technology needs a processor on each end of the
connection. Those processors can be very simple (relatively)
microcontrollers. There must be power to the computer portions as
well as whatever power is needed by the microphone and speaker
elements. Short story is that the radio end of the connection does
not currently (no pun intended) provide the power needed to run the
microprocessor. The currents for the speaker is AC and very small
and
the microphone is similar. There is no power source for the radio
end
of the bluetooth to be powered.
Not exactly true. The majority of Avionics Radios (especially in US) as
designed to drive a "Carbon Lookalike" microphone, so a phantom supply
of 5-10 volts is available via the microphone connector.
Of course we power the bluetooth headset with a battery and could also
power the
radio end with a battery. That would solve the power issue.
The next technical hurtle is to match the microphone and speaker
input/
outputs to the needs of the aviation radio. As I'm sure many have
discovered in the past, the "normal" headset you buy at the local
Radio Shack does not necessarily work with the aviation radio. The
microphone and speaker impedences of the low cost headset do not
match
the requirements of the aviation radio. The plugs on the cord ends
are also different (primarily the microphone cord). That's how the
aviation headset guys can charge more money; they understand the
radio
I/O requirements and their products match those requirements.
As mentioned earlier, the Avionics Microphone is a carbon based
lifeform. A carbon "lookalike" microphone will produce a signal in the
order of 800mV and so the radio will expect a signal of that order.
Off-the-shelf Bluetooth hardware is unlikely to produce that level of
signal.
Very true. The headset end could be a standard Bluetooth device, but the
A bluetooth system would have to mimic those impedence requirements
and connector systems.
Of course with all the existing bluetooth headset designs on the
market, the
real product is the radio end of the equation. Design for power,
microprocessor, impedence matching in a small package that plugs into
existing radio systems.
In my opinion that is a lot of "extra" just to get rid of a headset
cord. I think the market would be verk small for the effort expended
to produce a working system.
radio end would be a "Special", which a special price.
Lastly, Bluetooth works on very small signal levels and I am not sure
how well it will perform with a 5 Watt Transmitter not very far away,
and maybe a 200 Watt Transponder as well.
This looks like a solution looking for a problem.
Tim Newport-Peace tnp@xxxxxxxxxxxxxxxxx
Skype: tnp-laptop
A system admin's life is a sorry one. The only advantage he has over
Casualty doctors is that malpractice suits are rare. On the
other hand, A&E doctors never have to deal with patients installing
new versions of their own innards!
.
- References:
- Bluetooth Microphone?
- From: Gary Emerson
- Re: Bluetooth Microphone?
- From: SoaringXCellence
- Bluetooth Microphone?
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