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Re: a launchable rocket

From: Michael Sharp <>
Date: Wed, 01 Jul 1998 18:01:42 -0500

Jim Stiles wrote:
> 
> I am working on some fairly advanced rockets with a friend - we are

<snip>

Jim, 
I am perhaps the only other person on this list that was once certified
(ATF licensed as well) to fly high-powered rockets. I used an I-Max on
and H sized motor. I could have gone to J-sized but after my initial
certification, I got out of rocketry totally. Reason: Certification
costs, annual recertification with the Bureau of Alcohol, Tobacco and
Fire Arms, and the costs of motors, not to mention, that because of
recent laws, its illegal to own high powered motors unless you just
happen to have a bunker in your back yard. BTW, for the rest of reading
this post, yeah.. I know its not a "wearable issue", so I'll be short
and to the point. And if you're wondering why the ATF is involved, its a
whole can of worms.. basically, they're worried about safety issues
concerning high-powered motors.

> The parameters for the space available is that it is as long as it needs to
> be, 6 inches in diameter, and the whole system will be subject to lots of
> G's (like in the low hundreds range, depending on motors, etc).

In this case the *best* way to make a computer is to go totally i.c. You
can buy small computer made just for data logging, but if you're a
programmer, and dont mind working with 8-bit, you can use the Microchip
16c74. It has an 8-channel A/D converter on board, and 4k of program
space.. contact me if you need more specs... People that I know have had
equipment *destroyed* during launch, because good constructions tactics
where not used. I've seen boards blown to shreds, not to mention good
working camcorders (used in flight) totally trashed during acceleration.
You *must* build a good, sturdy board, possible reenforced if possible,
if you're going to make this work. Battery power need only be powerful
enough for the launch and recovery. You can keep your logger "hot" with
ground support equipment until launch.

> significant issue - I ran a TI micro system almost 20 years ago that had
> enough cycles to do this stuff (although the OS was BASIC, so presumably
> something real will require a little more horsepower).

If you're interested in a BASIC chip, there is a BASIC version of the
8052 out (8052AH-BASIC). It has an 8k BASIC interperter on board, and
can access 64k of ram. I built a mobile robot around one of these i.c.s.
BTW, JameCo has these 8052's and a company named Prologic has the board.
Again, contact me if you need further assistance.

> 
> If anyone has suggestions (OS, processor, A/D interfaces, etc), I would
> love to hear them.

Yeah.. I put 3 years of research into making an accelerometer. I have an
ultra-simple design that costs just a few dollars, and can out put an
analog (0-5v) signal proportionate to acceleration.. I'll give you the
basic design if you want it...

OK.. "Cyborgs" I've said enough. If anybody else has anymore rocket
questions they would like to ask me, please email directly. Thank you.
-Mike :)+<

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