Decting Vibration

GaryB

We have a rocket project·where we want to use a Basic Stamp to detect and record vibration during the flight. I've seen the Piezo strip, but looking though the forums, we haven't been able to figure out how to program it to record vibrations.

Questions:
1. Is the Piezo strip the best way to detect vibrations?
2. If not, what would do the job?
3. Regardless of sensor, we need assistance in writing/modifying the code, is there help somewhere?

Thanks in advance - Gary

Franklin

There is usually sample code on the product page for the product you are interested in using.

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- Stephen

GaryB

Yeah, and I got those and what it shows is that each product works. However, in the case of the Piezo, it shows it as a switch, but not how to make it detect vibration, which is what I want to do. And, is this the best sensor to measure vibration?

Gary

Franklin

You have to decide what it is you need to measure and to what tolerance and then decide what is best for you. What is it you want to measure? Do you need quantitative data or just ""there is vibration" type data?

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- Stephen

GaryB

Tolerance isn't too too important. We're looking to determine the amount of vibration (if any) through out the rocket flight and then see if there is anything that we can do to reduce the vibration.

We are using two as identical as possible high powered rockets with the same stamp/sensor shifted from one rocket to the other to establish some baseline data. Then we will modify one of the rockets to see if we can reduce the vibration. So with that in mind, which sensor makes the most sense (pun intended)? And, once that is determined, how do we program it?

Thanks - Gary

Franklin

For that you would use an accelerometer, probably 3 axis and some form of datalogger.

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- Stephen

GaryB

Thanks, Stephen. THe accelerometers that I have seen list operational g forces considerbly less that wha'ts exeperienced in our rockets. At least the ones I've seen from Parallax.

kf4ixm

You could use either the 2 axis or 3 axis accelerometer for this, there is sample code on the store product page for the accelerometers that will debug out the g-force of the axis to the screen, this could be ported (changed from debugging out to the screen to outputting values to a usb drive) to a usb datalogger that parallax also sells to record the g-forces in 1/100 of a g onto a removable usb thumb drive.

GaryB

OK, I've got each and a USB datalogger. My concern is/was that they are rated at +-3g's. What happens when those g forces are exceeded?

kf4ixm

i have not tested this, but i suspect (assume) the readings will just 'top out' at the ends of thier ranges, at least till the g-forces get to where mechanical damage to the sensor occours, and im not sure what that limit is either.

GaryB

OK, we'll giver er a try. Thanks for your input.

Gary