At 05:39 PM 12/31/00 -0500, Sean Breheny wrote:
>Hi Dave,
>
>Ok, it sounds like you are talking about problems
>associated with using these systems for parachute
>ejection. I thought you meant there were significant
>problems with using accelerometer-based altimeters for
>simple rocket altitude logging. If the rocket launch
>fails in that way, I would hardly expect accurate
>altitude data :-)

It's a common fault in design though, assuming that what the sensor tells
you means something that it doesn't, necessarily.


>I just thought of another thing that you (or someone
>else on the list) might be knowledgeable about: my
>altimeter contains one crystal and one ceramic
>resonator. Considering the mass and thrust of my
>rocket, it should experience a peak acceleration of
>about 14 G. Would this damage either the xtal or
>resonator?


Hard to say.  I've seen failures that looked like stopped clocks. I would
expect crystals to be more problematic than resonators. I would certainly
mount the crystal so that the maximum force was through the long axes of
the case, rather than through the thin part of the case.

Also, springy battery contacts are to be avoided.


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