Jump to content


Photo

Chronograph calibration / precision experiment suggestion.


  • Please log in to reply
28 replies to this topic

#1 WihGlah

WihGlah

    Planet Eclipse FanBoy

  • Members
  • PipPipPipPipPip
  • 1,369 posts
  • Gender:Male
  • Location:England

Posted 09 September 2013 - 05:12 PM

I have made an observation that a particular brand of chronograph is calibrated to give higher readings than the majority of others.

 

I propose Punkworks conducts a test to compare chronograph readings between several commonly used chronographs to see how reliable they are.

 

1. Chrono a marker to 300fps

2. Fire the marker across as many chronographs as possible and record the values of each chrono.

3. Calculate the differential to the usual Punkworks Chrono. (baseline value)

 

 

Analysis:

a. Variance of the mean of each chrono compared to the baseline mean.

b. Standard deviation within a chrono's values and variance from the baseline.


Posted Image

Proudly sponsored by Eclipse and LIPS


#2 bassfisher

bassfisher

    Senior Member

  • Members
  • PipPipPipPipPip
  • 2,098 posts

Posted 09 September 2013 - 11:42 PM

Interesting. 


Carolina Riot Scenario Team

#3 Cyco-Dude

Cyco-Dude

    Member

  • Members
  • PipPip
  • 177 posts
  • Gender:Not Telling
  • Location:Dayton, OH

Posted 10 September 2013 - 02:06 AM

I have made an observation that a particular brand of chronograph is calibrated to give higher readings than the majority of others.

 

and which brand / model would that be?



#4 HeroForADay

HeroForADay

    #1

  • Moderator
  • PipPipPipPipPipPipPipPip
  • 8,810 posts
  • Gender:Male
  • Location:Calgary, Alberta, Canada

Posted 10 September 2013 - 02:10 AM


I have made an observation that a particular brand of chronograph is calibrated to give higher readings than the majority of others.

 
and which brand / model would that be?

Likely the Virtue one. There have been reports that it has a tendency to read high; although I'm unsure if others just read lower. Would be a good test for sure.

#5 cockerpunk

cockerpunk

    All the Dudes

  • Moderator
  • PipPipPipPipPipPipPipPip
  • 9,045 posts
  • Gender:Male


Posted 10 September 2013 - 08:25 AM

interesting, as i too have noticed there is a difference in several different chronos ....

i wodner if we could derive actual velocity by a more accurate method, and then compare each chrono to a standard ....


The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#6 kingJurzy

kingJurzy

    OFFICIAL TechPB's best member 2012

  • Members
  • PipPipPipPipPipPipPipPip
  • 9,054 posts
  • Gender:Male
  • Location:Bay Area, California


Posted 10 September 2013 - 08:58 AM

Wouldn't you need more than one of each type of chrono to see if there are discrepancies in the readings?


FEEDBACK: 23/0/0


#7 TK-421

TK-421

    Me So Horny! :D

  • Moderator
  • PipPipPipPipPipPipPipPip
  • 25,778 posts
  • Gender:Male
  • Location:Austin, Texas

Posted 10 September 2013 - 10:39 AM

How would you figure out if it was a difference in chronographs or just a difference in the marker? Take the average across several shots? Or is there a marker that will consistently fire the exact same fps every single time?



#8 BurningPlaydoh

BurningPlaydoh

    Blow-dough'ed

  • Members
  • PipPipPipPipPipPipPip
  • 5,280 posts
  • Gender:Male
  • Location:Twin Cities, MN

Posted 10 September 2013 - 10:48 AM

Use a high-speed camera and distance narkers to calculate the actual shot velocity?

As for shot to shot differences just shoot over both chronos at the same time. The Clock is really small.
Use a high-speed camera and distance narkers to calculate the actual shot velocity?

As for shot to shot differences just shoot over both chronos at the same time. The Clock is really small.

#9 XGC_Cheevo

XGC_Cheevo

    Pod Scalping You

  • BST Moderator
  • PipPipPipPipPipPip
  • 2,748 posts
  • Gender:Male
  • Location:Mitchell, SD

Posted 10 September 2013 - 11:46 AM

I'd be willing to let Bryce or Gordon use my Clock if they want.  I could even hand it off this weekend at GBG if they are there.



#10 cockerpunk

cockerpunk

    All the Dudes

  • Moderator
  • PipPipPipPipPipPipPipPip
  • 9,045 posts
  • Gender:Male


Posted 10 September 2013 - 12:13 PM

i wonder if we could use sound to measure it over about 1 foot. probably have to be a very highly damped room .... mmmmm

the issue is we are measuring a constnatly slowing target. so while me and bryces optial chronos show us very easily where in the flight path of the ball the speed is averaged over, radar style chronos do not. it could be simply that the focal distence is different for example.

but again, we need a method, more accurate and more trusting, to establish a true speed for each shot.

 

EDIT: high speed camera isn't fast enough BTW, at least ours isnt. when the camera is placed perpendicular to a the barrel, paintballs come out as dashes ... this is because the frame rate isn't fast enough to get a nice crisp image.


Edited by cockerpunk, 10 September 2013 - 12:17 PM.

The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#11 unfated33

unfated33

    Punk Engineer

  • Members
  • PipPipPipPip
  • 865 posts
  • Gender:Male
  • Location:Charlotte, NC

Posted 10 September 2013 - 01:43 PM

If you can get access to a pressure plate limit switch, you could set up a target at a known distance with the plate attached.  I'm not sure how you'd start the signal - maybe photoelectric switch at the exit of the barrel? - but you could then measure velocity based on the time to hit the target and the exact distance from marker to target.


Happiness... is a warm mechanical marker

Mechanical Marker Fan: Azodin Kaos-D / Tippmann Crossover

#12 XGC_Cheevo

XGC_Cheevo

    Pod Scalping You

  • BST Moderator
  • PipPipPipPipPipPip
  • 2,748 posts
  • Gender:Male
  • Location:Mitchell, SD

Posted 10 September 2013 - 01:51 PM

They could possible use the kick machine?  Set up to trigger a signal when the kick is felt when the marker is fired?



#13 unfated33

unfated33

    Punk Engineer

  • Members
  • PipPipPipPip
  • 865 posts
  • Gender:Male
  • Location:Charlotte, NC

Posted 10 September 2013 - 02:09 PM

The kick machine could possibly work, but with the velocity/distance ratio being so small, I'm nervous that any errors that come from the fraction of time between when kick is detected and the paintball is moving toward the target could give you a consistent but inaccurate velocity - especially if you have to significantly reduce the distance to avoid the paintball shedding velocity.  I'd thought about measuring off a trigger switch or board input signal, but that could possibly have the same issue.


Happiness... is a warm mechanical marker

Mechanical Marker Fan: Azodin Kaos-D / Tippmann Crossover

#14 WihGlah

WihGlah

    Planet Eclipse FanBoy

  • Members
  • PipPipPipPipPip
  • 1,369 posts
  • Gender:Male
  • Location:England

Posted 10 September 2013 - 02:31 PM

 

I have made an observation that a particular brand of chronograph is calibrated to give higher readings than the majority of others.

 

and which brand / model would that be?

 

 

 

The clock


Posted Image

Proudly sponsored by Eclipse and LIPS


#15 JGARRIGUES0001

JGARRIGUES0001

    idk

  • Members
  • PipPipPipPipPip
  • 1,005 posts
  • Gender:Male
  • Location:Florence, Ky

Posted 11 September 2013 - 11:52 PM

Talk to those guys who have that youtube channel called "The Slow Mo Guys" or whatever it is.... if there was something cool they could get out of the video, something they could shoot and upload for their own youtube channel maybe they'd let you use the equipment or come over themselves. I've seen their vids where they go out of their way to make a cool video. But I have no idea where they are, or where you are so that is probably a long shot... idk just thought id throw it out there.


Edited by JGARRIGUES0001, 11 September 2013 - 11:53 PM.


#16 swiftblade13

swiftblade13

    he that is

  • Members
  • PipPip
  • 177 posts
  • Gender:Male

Posted 14 September 2013 - 11:27 PM

if all else fails you compare the chronographs to a calibrated and certified(?) ballistic laser chronograph.



#17 Troy

Troy

    What... is the air-speed velocity of an unladen swallow?

  • Members
  • PipPipPipPip
  • 896 posts
  • Gender:Male
  • Location:Oklahoma City

Posted 17 September 2013 - 04:26 PM

I think the best way to do this is to calibrate the object that you are taking the speed of. I suggest dropping a steel ball from a fixed height.

 

Btw, after noticing a 20 fps deviation at the last field I played on between chronos, I'm very interested in the results. It's my understanding that the timing chips can "wander," unpredictably, over time in these devices... so readings between a new device and an old one may not be similar, even if they are the same model.


Edited by Troy, 17 September 2013 - 04:31 PM.

\m/

#18 madsnipes

madsnipes

    TechPB's Jailbot

  • Members
  • PipPipPipPipPipPipPip
  • 5,038 posts
  • Gender:Male
  • Location:In one of those "High-Tech" caves with Wi-fi

Posted 19 September 2013 - 04:53 PM

 

 

I have made an observation that a particular brand of chronograph is calibrated to give higher readings than the majority of others.

 
and which brand / model would that be?

Likely the Virtue one. There have been reports that it has a tendency to read high; although I'm unsure if others just read lower. Would be a good test for sure.

 

I've heard this too, that the virtue ones read high...


#32 "Dusty" of the Devil Dogs. Give us a like if you want - Devil Dogs Paintball

TechPBsig_zpsbc0cb057.jpg


#19 Demon

Demon

    Master Tech

  • Members
  • PipPipPipPipPip
  • 2,086 posts
  • Gender:Male
  • Location:Omaha Nebraska


Posted 19 September 2013 - 11:56 PM

do not put the chronoes next to each other an attempt to read the velocity, they will affect each other and improperly read.


this is borderline pornography.......(bookmarks thread)

Captain of the Westside Paintball Team

My Feedback


#20 swiftblade13

swiftblade13

    he that is

  • Members
  • PipPip
  • 177 posts
  • Gender:Male

Posted 23 September 2013 - 12:34 PM

do not put the chronoes next to each other an attempt to read the velocity, they will affect each other and improperly read.

UNLESS one of the two chrono's is a laser break-beam ballistic chronograph.



#21 cockerpunk

cockerpunk

    All the Dudes

  • Moderator
  • PipPipPipPipPipPipPipPip
  • 9,045 posts
  • Gender:Male


Posted 23 September 2013 - 03:57 PM

i guess the problem i have with this is that if we want to calibrate chornos, i'd like a standard to calibrate better then just a chorno we think is right.

is there any easy way, to define quite literally, a foot per second, using essentially a ruler and a clock?


The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#22 Demon

Demon

    Master Tech

  • Members
  • PipPipPipPipPip
  • 2,086 posts
  • Gender:Male
  • Location:Omaha Nebraska


Posted 23 September 2013 - 04:48 PM

high speed camera against a back drop of black and white lines to determine distance over time, similar to what you see on myth busters could calculate an exact velocity.


this is borderline pornography.......(bookmarks thread)

Captain of the Westside Paintball Team

My Feedback


#23 BurningPlaydoh

BurningPlaydoh

    Blow-dough'ed

  • Members
  • PipPipPipPipPipPipPip
  • 5,280 posts
  • Gender:Male
  • Location:Twin Cities, MN

Posted 23 September 2013 - 10:09 PM

high speed camera against a back drop of black and white lines to determine distance over time, similar to what you see on myth busters could calculate an exact velocity.

Use a high-speed camera and distance narkers to calculate the actual shot velocity?

As for shot to shot differences just shoot over both chronos at the same time. The Clock is really small.
Use a high-speed camera and distance narkers to calculate the actual shot velocity?

As for shot to shot differences just shoot over both chronos at the same time. The Clock is really small.



#24 cockerpunk

cockerpunk

    All the Dudes

  • Moderator
  • PipPipPipPipPipPipPipPip
  • 9,045 posts
  • Gender:Male


Posted 24 September 2013 - 01:53 PM

high speed camera against a back drop of black and white lines to determine distance over time, similar to what you see on myth busters could calculate an exact velocity.

i already said why this wont work.


The ultimate truth in paintball is that the interaction between the gun and the player is far and away the largest factor in accuracy, consistency, and reliability.

And yes, Gordon is the sexiest manifestation of "to the front."


#25 unfated33

unfated33

    Punk Engineer

  • Members
  • PipPipPipPip
  • 865 posts
  • Gender:Male
  • Location:Charlotte, NC

Posted 24 September 2013 - 02:51 PM

 

high speed camera against a back drop of black and white lines to determine distance over time, similar to what you see on myth busters could calculate an exact velocity.

i already said why this wont work.

 

Yeah, I think you're going to be better off with an instrument that will switch on/off a relay when the paintball passes or makes contact with an object.  It would seem like two photo eyes switching a timer across a known distance apart could work if you can measure the distance in a range where the paintball is not dropping significantly.  Either that, or the sensitivity of the eye would need to cover a broad vertical range without generating false positives.  That's the cheapest solution I can come up with, though I don't think it's going to be as accurate as a pressure plate switch.


Happiness... is a warm mechanical marker

Mechanical Marker Fan: Azodin Kaos-D / Tippmann Crossover

#26 Troy

Troy

    What... is the air-speed velocity of an unladen swallow?

  • Members
  • PipPipPipPip
  • 896 posts
  • Gender:Male
  • Location:Oklahoma City

Posted 25 September 2013 - 11:37 AM

 

 

high speed camera against a back drop of black and white lines to determine distance over time, similar to what you see on myth busters could calculate an exact velocity.

i already said why this wont work.

 

Yeah, I think you're going to be better off with an instrument that will switch on/off a relay when the paintball passes or makes contact with an object.  It would seem like two photo eyes switching a timer across a known distance apart could work if you can measure the distance in a range where the paintball is not dropping significantly.  Either that, or the sensitivity of the eye would need to cover a broad vertical range without generating false positives.  That's the cheapest solution I can come up with, though I don't think it's going to be as accurate as a pressure plate switch.

 

 

The object's speed being measured needs to be calibrated, using a marker to shoot a projectile introduces another, unnecessary, variable.


\m/

#27 unfated33

unfated33

    Punk Engineer

  • Members
  • PipPipPipPip
  • 865 posts
  • Gender:Male
  • Location:Charlotte, NC

Posted 25 September 2013 - 03:30 PM

I'm not sure I followed what you were trying to say, but I concede that there's no reason to use a paintball marker to test velocity.  If you know the distance a projectile crosses between two switch points, you can use output relays from each switch to start and stop a timer.  Then you can calculate velocity by the distance divided by the time.  Did you mean error induced by the accuracy of the switch response?  That's a point I'd potentially concede with a photoelectric switch.


Happiness... is a warm mechanical marker

Mechanical Marker Fan: Azodin Kaos-D / Tippmann Crossover

#28 Troy

Troy

    What... is the air-speed velocity of an unladen swallow?

  • Members
  • PipPipPipPip
  • 896 posts
  • Gender:Male
  • Location:Oklahoma City

Posted 26 September 2013 - 02:57 PM

I'm not sure I followed what you were trying to say, but I concede that there's no reason to use a paintball marker to test velocity.  If you know the distance a projectile crosses between two switch points, you can use output relays from each switch to start and stop a timer.  Then you can calculate velocity by the distance divided by the time.  Did you mean error induced by the accuracy of the switch response?  That's a point I'd potentially concede with a photoelectric switch.

 

The timing chips on Doppler devices are, at least, suspected to drift over time (which, if that suspicion is true, could cause them to be less accurate). Can we guarantee that the photoelectric method of measuring distance traveled over time doesn't have the same problems?

 

The problem is that you are using one device (like the photo electric based shooting chrony that both punkworks and I use) with a % of uncertainty to calibrate a device that has it's own, much higher, % of uncertainty measuring the speed of an object that has an speed with an unknown % of certainty.

 

Where are your controls? We can conduct the above experiment, then feed all the results (assuming we have enough data) into an ANNOVA and figure out what's going on... BUT, I prefer to run experiments as cleanly as possible.

 

I don't think that we should rely on anything that uses a timing chip as a control... if we can help it. I suggested dropping a ball from a known height, so we can calculate it's speed at any position on it's fall path given it's distance and rate of acceleration. We can compare the accuracy of a photoelectric device with our, estimated, speed projections and eliminate the possibility of timing chip drift effecting the measured speed (or we could adjust accordingly). This method will, also, give us the added benefit of being repeatable all over the country. Anyone with an object of sufficient density and low surface area could give us data. I could test my shooting chrony in my garage, you could test your handheld Doppler, someone could use a radar gun, etc.


Edited by Troy, 26 September 2013 - 03:01 PM.

\m/

#29 The Recballer

The Recballer

    South Florida Shockers

  • Members
  • PipPipPipPip
  • 909 posts
  • Gender:Male
  • Location:Miami, Florida

Posted 10 October 2013 - 07:46 PM

Wouldn't the inconsistency of the marker blow the whole test?


Interested in DMs, NTs, and Dye Cockers

- Dye Owners Club -

South Florida Shockers #16

 





1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users