Peter L. Peres wrote:

>> 2. For free-fall parachuting - you just passed 3,000' (2,000', whatever)
>> going too fast - BEEP! pull now!
>
>Same answer as above, imho, but I was under the impression that free
>jumping has a limit on the speed at which you can pull with certain
>umbrellas. So this is better answered by a speedometer (heated thermistor
>probably). The height problem is solved by a VERY special barometric
>device that is a SAFETY device and is mounted on the harness proper.

Having done both a jump and electronics I don't think I'll be relying on a PIC,
even if I programmed it ;-) The altimeter sky-divers use is calibrated against
the plane's altimeter on each jump. Whatever it is has to be near-perfect, the
chutes I used as a learner have *never* failed to open. Not once. Ever. We still
carry a backup, and learn how to use it.

>> 3. I have a friend into model rockets - how high do they get?
>
>Almost everything that you can build @ home, including SMT, is too heavy
>to ride on all but the heaviest model rockets. 

The rockets you want to know the altitude of tend to be the bigger ones anyway.
I've often thought about getting telemetry, but the small size makes it a tough
challenge. The real question I usually have though is not how high, but where
the HELL is it? My brother launched a 3 stager with D engine booster in less
than ideal conditions, and well, we found the second stage over half a mile
away, and the third stage could be still up there.
-- 
Bob Cousins, Software Engineer.
Home page at http://www.lintilla.demon.co.uk/