0-15000 feet (0-4572 meters) altitude measurement with electronic pressure sensor

http://focus.ti.com/docs/mcu/catalog/resources/appnoteabstract.jhtml?familyId42&abstractName=slaa254  
for an example.

Dave

That depends on your accuracy requirements.  For really inexpensive,
fairly accurate for the money sensors I would use a absolute pressure
sensor from Freescale semiconductor; they're available from Digi-Key,
they don't cost too much, they look like an 8-pin DIP on one side and
have a hose nipple on the other -- they're hard to beat.  Get one with a
range of 0-15psi.

Yes, and I don't think you'll have to amplify it too much.

Findable on the web, I should imagine.  IIRC you lose more than 5 psi at
15000 feet, but it's been a while.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

On 2005-10-25 14:33:43 +0200, <Daniel Kolizev> said:


If you want an accurate reading, it would be better to go to the
aviation shop and buy an Altimeter. If you need to record the altitude
along the flight, you need a barograph, and you can find one at a
glider field. By now I think they use GPS with data recording as GPS
can deliver an altitude data.

Regards,

MLB

The relationship between height and pressure is given on this page:

http://en.wikipedia.org/wiki/Atmospheric_pressure

I'm not sure which sensor you need.  Use the equation to find out what the
range of pressure should be from the given height, then get the sensor which
most closely matches that range.

Brent S.

http://www.vaisala.com/businessareas/instruments/products/barometricpressure/pmb100

These look they will need a transmitter or something similar in addition
to the barometer module.

Additionally, you may want to try a radiosonde or similar instrument.
The sondes are already meant to go with a balloon. You will need some
sort of receiver however. I am only familiar with the one used by the
Navy but I would imagine there are others out there.

http://www.vaisala.com/businessareas/measurementsystems/soundings/products/radiosondes/vaisalaradiosonders80
Just a thought.

P = 1.013 - (1 - (0.0065-h)/288)^5.255

Pressure in Bar, h in metres.

Clifford Heath.

| Which off-the-shelf electronic pressure sensor component (part number) would
| be used to measure altitude of a baloon starting its journey from sea level
| (0 meter) to 15000 feet (4,572 meter) ?

Well, this doesn't exactly answer your question as asked, but it might
(or might not) be more useful than actually answering your question.
(Which others have done anyways.)  And you did ask in
rec.models.rc.air, so I'll answer in that context ...

If you're looking to record the altitude over time, and want it small,
accurate and relatively cheap, get the RAM2 at
http://home.epix.net/~rcbrust/ .  It costs about $100 and will record 9
hours of altimeter data at one data point/second with a resolution of
about one foot.  And it only weighs 7.5 grams.

If you're looking to know how high your balloon is and want this
transmitted in real time, you may want a variometer.  There's several
to choose from, but the Picolario at http://www.picolario-usa.com/  is
a popular one.  Alas, it costs just short of $400.  (But there are
other options that are cheaper, but have fewer options.)  I don't know
if these would have 15,000 feet of range, however -- though you might
be able to use a scanner and a highly directional antenna to increase
the range.

Another option is the Flight Data Recorder at
http://www.eagletreesystems.com/ , and it can both transmit and record
information, and can keep even more information than just altitude.
It also has a GPS option that might be useful.

Note that these altimeters give altitude data that is a good deal more
accurate than a GPS.  You may or may not care, but the difference is
there.

Of course, if you want something that you can tie into something else
on the balloon, then none of these are likely to be what you want, but
you might find them useful as a starting point of something you
homebrew.

--
Doug McLaren, dougmc@frenzy.com              / is the root of all directories.