Vibration Monitor (Hyde, Wanttaja?)

Pete Schaefer wrote:
Cool. Maybe we should do entire airplanes around bluetooth. That way, any
geek with a PDA can hack our planes when we fly by. Yeah, **** all these EMI
worries!

Sorry, but that idea sounds like an awfully inviting drive-by target.

Bluetooth has a limited range -- about 10m absolute max. Do you often
fly overhead geeks at 36ft AGL?

Not only that, but Bluetooth also allows closed networks to be set up --
no access to anyone outside the selected group of devices.

Sorry, but you shouldn't get all sarcastic about someone suggesting a
technology that you clearly don't have a clue about.

Frank

Frank:

I do have quite a clue about EMI, and clearly have a better clue than you
about systems engineering in general. Here's a question for you:

Why bother?

If you're trying to cert bluetooth for aviation, maybe with the thought of
selling some other bluetooth product that you think you can make a big chunk
of cash with, then, yeah, maybe going off to play with bluetooth on your
airplane makes sense. Personally, I can't see it. Maybe it makes sense for
using it to reprogram boxes on your airplane, but to go to the extent of
making it useful/safe in flight....nah. Way too much effort for too little
return, given that the inclusion of an RS-232 port is so freakin' easy.

If you have some other goal in mind, maybe some other sensing or data fusion
tech (e.g. may you have a huge array of air data sensors for some advance
stall detection method), then you have to look at whether or not the tech
risk buys you something that you can't get otherwise. Why bluetooth rather
than the 1/2 dozen other wired data communication protocols (e.g. 1392, .
422, 232, 485, CAN, etc.) that are out there?

I get rather frustrated with people who get really !@#$ing enamored with
technologies for implementation and loose sight of what their goals are. All
too often, risk variables get introduced where none is warranted, resulting
in zero or negative value added. I beat on my guys daily about issues like
this. (Kelly Johnson (...yeah, I work at that place.....) had a lot to say
about where it was acceptable to take project risks..too bad so much of it
never got captured in "the rules").

So, back to Blue Tooth....

Why bother?

For data collection, I've already got a half-dozen options in my hip pocket
that I know will work just fine with very well understood EMI issues that I
know how to mitigate. What's my goal? Blue tooth airplane or getting the
data for some other purpose?

I have very little room for Geek Factor on any airplane that I'll ever
build. If it can't buy it's way on (I'd lump Blue Tooth in here), then !@#$
it.


Pete

P.S. I just got done with a 5 hour drive and am tired as all !@#$. I've got
4 beers in me to diffuse stress. Please forgive my abbrasiveness. I'm not
really that bad of a guy. I just don't want people to pursue ideas that
will get them killed.


"Frank van der Hulst" wrote in message
...
Sorry, but you shouldn't get all sarcastic about someone suggesting a
technology that you clearly don't have a clue about.

Pete Schaefer wrote:
Frank:

I do have quite a clue about EMI, and clearly have a better clue than you
about systems engineering in general. Here's a question for you:

Why bother?

For the same reason that we build planes instead of buying them.

If you're trying to cert bluetooth for aviation, maybe with the thought of
selling some other bluetooth product that you think you can make a big chunk
of cash with, then, yeah, maybe going off to play with bluetooth on your
airplane makes sense. Personally, I can't see it. Maybe it makes sense for
using it to reprogram boxes on your airplane, but to go to the extent of
making it useful/safe in flight....nah. Way too much effort for too little
return, given that the inclusion of an RS-232 port is so freakin' easy.

I agree totally. except maybe about RS-232. I suggest that some sort of
current-based rather than voltage-based signalling would be more
noise-immune. Bring back 20mA current loop! :-)

If you have some other goal in mind, maybe some other sensing or data fusion
tech (e.g. may you have a huge array of air data sensors for some advance
stall detection method), then you have to look at whether or not the tech
risk buys you something that you can't get otherwise. Why bluetooth rather
than the 1/2 dozen other wired data communication protocols (e.g. 1392, .
422, 232, 485, CAN, etc.) that are out there?

The TWO key ideas in the proposition (wasn't mine, BTW) were wireless
comms and self-powered. If you can do BOTH of those, then wired comms
and power is best. Wireless comms has been pretty much solved. For
example, I saw a projection in an engineering mag that within 25 years
wireless will replace wired as the cheapest comms technology to the home.

But without "self-powered" it is pointless. Are there any devices out
there that can turn (e.g.) vibration into *useful* amounts of electricity?

I get rather frustrated with people who get really !@#$ing enamored with
technologies for implementation and loose sight of what their goals are.

Hmmm... so what are *my* goals? Maybe I want the geekiest plane on the
block? I suggest that one or other of your 4 beers has introduced some
patronisation (as well as abrasiveness) into your system.

All
too often, risk variables get introduced where none is warranted, resulting
in zero or negative value added.

I'll choose what risks are warranted on *my* project, thanks.

I beat on my guys daily about issues like
this. (Kelly Johnson (...yeah, I work at that place.....) had a lot to say
about where it was acceptable to take project risks..too bad so much of it
never got captured in "the rules").

This is fine where *you* get to set the goals.

So, back to Blue Tooth....

Why bother?

*With* self-powered devices, it gives options not available via wired
systems.

For data collection, I've already got a half-dozen options in my hip pocket
that I know will work just fine with very well understood EMI issues that I
know how to mitigate. What's my goal? Blue tooth airplane or getting the
data for some other purpose?

I have very little room for Geek Factor on any airplane that I'll ever
build. If it can't buy it's way on (I'd lump Blue Tooth in here), then !@#$
it.


Pete

P.S. I just got done with a 5 hour drive and am tired as all !@#$. I've got
4 beers in me to diffuse stress. Please forgive my abbrasiveness. I'm not
really that bad of a guy. I just don't want people to pursue ideas that
will get them killed.

Hey, I prefer to talk straight too. And also don't want people to kill
themselves. But if people don't experiment with Experimental category
aircraft, then nothing is going to change.

Frank

Frank van der Hulst wrote:

*With* self-powered devices, it gives options not available via wired
systems.


Couple of sources. This is a hot research area.

http://www.sandia.gov/media/NewsRel/...eredsensor.htm

http://www.perpetuum.co.uk/

Frank van der Hulst wrote:

Why bother?


*With* self-powered devices, it gives options not available via wired
systems.


Even if you have to run 12V to it, in a metal airplane that will only be
one wire and one connection. Assuming they can build a wireless device
that can stand up to typical airplane abuse for a while*, this would
make for a much simpler and safer installation. At these power levels,
the EMI issue is a red herring that would be easily defeated with a
$0.98 roll of aluminum foil, and once defeated on the ground the
problem isn't likely to pop back up in flight (like loose cabling will).

IMHO

*It seems that your standard store bought router is designed to die
after a few years. I wouldn't trust this quality control with my
comfort. I barely trust it with my ability to read this newsgroup.


--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

So, what things on the airplane are you guys going to replace with
self-powered blue tooth devices?


"Ernest Christley" wrote in message
om...
Even if you have to run 12V to it, in a metal airplane that will only be
one wire and one connection. Assuming they can build a wireless device
that can stand up to typical airplane abuse for a while*, this would
make for a much simpler and safer installation. At these power levels,
the EMI issue is a red herring that would be easily defeated with a
$0.98 roll of aluminum foil, and once defeated on the ground the
problem isn't likely to pop back up in flight (like loose cabling will).

IMHO

*It seems that your standard store bought router is designed to die
after a few years. I wouldn't trust this quality control with my
comfort. I barely trust it with my ability to read this newsgroup.

Pete Schaefer wrote:
So, what things on the airplane are you guys going to replace with
self-powered blue tooth devices?

First thing would be Bluetooth headsets... no more cords tangling round
the cockpit.

Next would be various engine instruments... EGT, CHT, etc.

Maybe move the entire radio receiver out to a wingtip or somewhere well
away from the engine's RF noise. But I can't see that being
self-powered. Perhaps we could use Tesla's beam-power technology to run
those.

Frank

Frank van der Hulst wrote:
Pete Schaefer wrote:

So, what things on the airplane are you guys going to replace with
self-powered blue tooth devices?


First thing would be Bluetooth headsets... no more cords tangling round
the cockpit.

That's a good one. Keep an old pair if wired sets stuck in an
accessible hole someplace...just in case.


Next would be various engine instruments... EGT, CHT, etc.

Perfect. If the signal dies, the plane won't know it. The Cherokee I
trained in didn't even have a working EGT.


Maybe move the entire radio receiver out to a wingtip or somewhere well
away from the engine's RF noise. But I can't see that being
self-powered. Perhaps we could use Tesla's beam-power technology to run
those.

Frank

Oooh. You just lost me on that one. To much complication with the radio
to human interface there. You've got a device in front of the pilot to
select a station, which must transmit it to a device out on the wing,
which has to recieve and interpret it correctly, then transmit the
correct station's signal back over bluetooth. You'd still have to run
signal wires for the physical backup. I just don't see the advantage
when remoting the antennae is all that's necessary to avoid the engine EMI.

How about stress monitors built into the prop (I have no idea if anyone
makes such a thing). Would help you to carve a perfect prop.

Miniature temp probes and air pressure sensors that you can stick all
over the place. Would make it real easy to map out the pressure regions
on the airplane and design a better cooling system or decide if wing
modification would be necessary/beneficial.

Vibration sensors stuck inside control surfaces and different parts of
the skin. Early warning system for flutter. Might only give you time
for a short prayer, but it may save your butt if you can react quick enough.

Nothing is stopping anyone from doing any of this with wired sensors.
It would just be cleaner and easier if the wire can be left on the spool.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

"Frank van der Hulst" wrote in message
...
First thing would be Bluetooth headsets... no more cords tangling round
the cockpit.

That would be pretty nice. But now you need batteries in your headset to
power the audio amp.

Next would be various engine instruments... EGT, CHT, etc.

I guess you'd need some devices (i.e. wires) for routing the signal through
the firewall or around it. How much lighter would this be than, say, a
twisted pair for CAN?

Maybe move the entire radio receiver out to a wingtip or somewhere well
away from the engine's RF noise.
But I can't see that being self-powered.

The receiver could be, but not the transmitter. An antenna wire is probably
a lot lighter than running power out, so I guess that would need to stay in
the cockpit.

Pete Schaefer wrote:
So, what things on the airplane are you guys going to replace with
self-powered blue tooth devices?

I'm typing out loud here...

When I suggested bluetooth the other day, what I had in mind was a kit
that you would temporarily hang on an airplane for specific tests, much
like we hang all the orange on Navy aircraft for flight tests. Much more
accurate pitot-static, vib sensors, postion sensors, data loggers, etc.
You could, for example, have a kit for flight testing an RV-8. Pop it
on, do the tests, and remove it. Or it could be used for "external
stores" such as a camera.

Afterward, I contemplated replacing all signal wires with wireless. So
any wire not carrying power could be replaced. This might be especially
useful for a refit, where access is far more difficult than during
initial construction.

Other harebrained ideas...two planes in semi-close formation could
network via bluetooth. Why? Could be low prob. of intercept comms on a
private channel, sharing of nav data, text messaging, ipod music files.

There's an ongoing thread on rec.aviation.soaring on bluetooth and
cellphones aboard planes.