Need A Little Electronics Help To Measure Barrel Vibration

[dryhumor]

This may not apply to your device, but there is useful info here. Just another bit of information.

http://s7d2.scene7.com/is/content/C...2.1286872147.1595969473-2035131074.1595969473

 

[wwbrown]

From the datasheet The STANDBY pin is active when high, so if you applied a voltage at the supply voltage the device would go into STANDBY mode, which is a power-saving mode that allows the device to be brought back to life faster than if you just powered the device down when not in temporary use.

I agree you should get the output on an O-scope, if you can't find one local to you and still are not getting output I would encourage you to send it back. I can check it out on my scope if you want to send it to me for testing, but the guys at Analog Devices are experts, me I just dabble.

I can do the frequency analysis for you if you are having problems doing it, I use Octave which is an open source Matlab look- and act-alike that is extremely powerful and free. I would send you the script I used in Octave so you could install Octave on your computer and do the analysis on your own from that point on. This is not a big deal, there are lots that can do the same or better than I in Octave.

On the Arduino side of things I would make sure you use a board that was not built in china, I would worry about the quality of the output voltage. The black box schematic of the eval board does not show any power conditioning so the quality of the supply power will probably impact the quality of the output. This is not intended to appear disparaging towards Arduino, I think those boards and the community that supports them is fantastic, but at times you need to be a little more careful of where they were made.

On the issue of power conditioning have you used a bypass capacitor that the data sheet indicates? A bypass cap is connected between the input power and ground, they recommend a 1 microFarad capacitor as a bypass capacitor. The bypass cap allows noise on the input power to go to ground instead of the power supply input, a good cheap way to help clean up the power, I am surprised the evaluation board does not have one built in.

Maybe this helps,
wade

 

[CharlieNC]

Well I have it working!I downloaded an Arduino app to read voltage and display real time like a scope, and it shows vibration and movement as expected. Originally I was watching numbers go by on the screen which just was not adequate; my bad.

Attached it to a barrel and watched the instantaneous vertical spike due to the firing pin falling when the trigger was pulled. Interestingly the barrel response was not consistent.

Now to figure how to get readings to a file where I can work with the numbers.


Thanks for helping.

 

[gunsandgunsmithing]

Well I have it working!I downloaded an Arduino app to read voltage and display real time like a scope, and it shows vibration and movement as expected. Originally I was watching numbers go by on the screen which just was not adequate; my bad.

Attached it to a barrel and watched the instantaneous vertical spike due to the firing pin falling when the trigger was pulled. Interestingly the barrel response was not consistent.

Now to figure how to get readings to a file where I can work with the numbers.


Thanks for helping.

Hang some weight from the muzzle and watch what it does to frequency, and interestingly, amplitude..WHILE the bullet would be in the bbl. Then move the weight. Pretty cool!

 

[GeoffR]

How valuable is this information? That being the vibration and twist (if any) characteristics of a barrel? What would the interest be in a system that measured and analysed these characteristics without having to physically attach anything to the barrel?

The reason I ask is that I am involved in a project at one of our local universities that could possibly include this application. While the focus of this project is elsewhere, the technology being developed would dovetail quite nicely into this particular application.

The technology involves the use of optical (laser) interferometry using photonics (LiDAR) that samples at up to 500 kHz with measurement resolution (or sensitivity) of 1 nano metre (1/10th micron). The people involved in this project have extensive experience in vibration measurement and analysis generally and this particular optical approach is simply another way to do it.

I have spoken to the project leader (who is also my son - and a former shooter so he understands the requirements for the most part) and he agrees that we could fairly easily consider this application alongside the main focus of the project (that has nothing to do with ballistics).

If there was interest that is in being able to do this that is...

Obviously cost would be an issue but it doesn't get any better than when the development of one piece of technology can piggyback on the back of the development of another that is being funded from a different source! The costs associated with laser and other optical technology is dropping considerably as time goes by. Like with lots of other technologies.

So would there be any potential value in us considering this application further? What sort of interest might there be?

 

[rwj]

So would there be any potential value in us considering this application further? What sort of interest might there be?

Yes, but you don’t know what you don’t know!

 

[GeoffR]

Yes, but you don’t know what you don’t know!

I guess my initial question makes more sense.

How valuable is this information to hand loaders? That being the vibration and twist (if any) characteristics of a barrel?

 

[Dusty Stevens]

I spent over $10k to map vibration and position of a barrel muzzle in 2ms increments. The most valuable information came from dry firing and using that same datalogger with seismic sensors and a microphone. Taught me a lot about loading and tuner effect though.

 

[CharlieNC]

I would bet this could be applied to optimizing barrels which provide wider nodes.