quick chrono question

[Jotsy]

first of all, sorry if this isn't "deep" enough to be in the deep blue section. i just have a quick question relating to chronographs, specificall this post here in the "new ideas" thread.

http://www.automags.org/forums/showpost.php?p=2090595&postcount=29

- first, does a chrono still work properly if its placed at the end of a barrel looking down the barrel?
- how big is the actual chrono device? have any of you tried opening up a handheld chrono?
- is it possible to have the chrono output the speed of whatever's in front of it in real time? or how long does it take to take an actual reading? i'm more interested in how long it takes to register a reading, not necessarily how long it takes to calculate and display the data on the screen (if anybody knows that kind of information)

thanks

[grEnAlEins]

- first, does a chrono still work properly if its placed at the end of a barrel looking down the barrel?thanks
I do not see why not, It would measure the velocity the same way, just the direction is towards the chrono instead of away. Unless it cannot "see" down the barrel without causing problems. It seems that it would have trouble with sticking into the barrel in order to shoot waves down the barrel to read velocity without having some clearance issues.

What gave you the idea, was it the PnueVentures Inc Cyber 900? That has a chrono on the barrel.

"Also in 1996 the Shocker, manufactured by PneuVentures Inc., and distributed exclusively by Smart Parts (patent Oct 19, 1999) is the first electroneumatic paintball marker, PneuVentures and Smart Parts soon parted with PneuVentures in 1997 producing the Shocker, and PneuVentures producing the very advanced Cyber 9000 the first marker with built in LCD screen, also featuring built in chronograph!"

~http://www.ody.ca/~cwells/history.htm
Scroll down to 1996 for a pic

[magman007]

or just use the terrible invention vl came out with a while back, a barrel mounted chrono, that worked terribly.

Lets put it this way, there are too many variables in paintball to get a reasonable reading the way you want to. The big red chronos arent that accurate, handhelds arent that accurate, what makes you think your system would be better? and why?

also, why would i want to worry about my chrono system messing up in addition to everything else?

lets just face it, neat idea, but terribly unnecessary. it would never be adopted.

[Jotsy]

wow, i didn't know about that Cyber 9000 thing.

actually, there's a thread in the deep blue section discussing how to make an auto-regulating-self-chrono-ing marker (i guess my thread go moved :p ). something that would adjust its regulator based on the readings it got form the built in chrono.

my idea was to have a radar chrono (or a laser range finder) placed behind the ball looking down the barrel. probably either part of the bolt or using a hollow bolt that the chrono can "see through". this way, rather than just taking a reading and adjusting the next shot, it could take a reading while the ball is a predetermined distance down the barrel, do some magic calculations, and then adjust the pressure or dwell time accordingly to get the ball up to a perfect 300fps (or whatever fps you desire) at the exact moment it leaves the barrel (or effective barrel).

which is why i'm asking if it could actually look down a barrel, and if it could actually take readings in the split second while the ball is moving in the barrel. of course it would prob need some really fast high end super chip, but if we're talking about super markers then we might as well implement the best parts.

[grEnAlEins]

wow, i didn't know about that Cyber 9000 thing.

actually, there's a thread in the deep blue section discussing how to make an auto-regulating-self-chrono-ing marker (i guess my thread go moved :p ). something that would adjust its regulator based on the readings it got form the built in chrono.

my idea was to have a radar chrono (or a laser range finder) placed behind the ball looking down the barrel. probably either part of the bolt or using a hollow bolt that the chrono can "see through". this way, rather than just taking a reading and adjusting the next shot, it could take a reading while the ball is a predetermined distance down the barrel, do some magic calculations, and then adjust the pressure or dwell time accordingly to get the ball up to a perfect 300fps (or whatever fps you desire) at the exact moment it leaves the barrel (or effective barrel).

which is why i'm asking if it could actually look down a barrel, and if it could actually take readings in the split second while the ball is moving in the barrel. of course it would prob need some really fast high end super chip, but if we're talking about super markers then we might as well implement the best parts.

This should be possible. We can look at an SFT Shocker for this. If you were to use a "hollow" bolt with a hole down the middle lengthwise, then you could afix a lazer or radar system to the tip of the bolt guide. Doing the calculation of velocity should be quick enought that the system would still be able to maintain a high ROF. The question I have is would it be able to adjust dwell/psi fast enough to maintain a desireable ROF. I see no reason why such a system of adjustment could not work, but it seems to me that there is a need for some serious R&D.

[sunyjim]

The trick with the cyber 9000 is that it only needs one break eye beam.

Chronographs work one of 2 ways. The one that your familiar with is the radar chrono that sends out radar beams, it measures, then measures again for difference in distance over a set time. So speed over time is converted into FPS

The way most firearm chronographs work is the oposite, the distance is known, not the time, so the bullet flys over two optical sensors and because the machine knows the distance between the two, the speed can be calculated.

Well with the cyber 9000 the distance is known, it's the length of the barrel, the shot is fired electrically so you don't need a sensor at the bolt, just a sensor on the end of the barrel :which is what that thing on the end of the gun is. So the gun calculates the TIME from fired, to end of barrel and can calculate and display the FPS! :)

there was a crappy chrono out by brass eagle a few years ago. A black tube with a display.
here's a google link with good pic, http://www.maxs-sport.com/paintball-shop/details.asp?sprache=en&sessionid=2276095423050106662496534&Artikelnr=772-001
it works like the firearm design I mentioned. It knows the distance and calculates the time, you could rip it up, install the sensors on the barrel and then you would have a working built in chrono!

[grEnAlEins]

Well with the cyber 9000 the distance is known, it's the length of the barrel, the shot is fired electrically so you don't need a sensor at the bolt, just a sensor on the end of the barrel :which is what that thing on the end of the gun is. So the gun calculates the TIME from fired, to end of barrel and can calculate and display the FPS! :)
Yes, but with the system to adjust dwell or psi like he is talking about, this system (known distance, measure time) is too slow. By the time adjustments are made from ball 1, ball 2 has probably already been fired and is halfway down the barrel. The system would need to detect velocity as quickly as possible. Monitoring the ball as it moves through the barrel (instantanious velocity), as opposed to as it exits the barrel and finding the average rate (average velocity for distance x) is probably the best way to do this when the process needs to be quick. If you can monitor the ball right as it comes to optimim speed, the dwell/psi can be adjusted before the next ball is fired. This is my understanding of what Jotsy wants to happen, self velocity regulation done quickly to maintain consistancy and high ROF.

[Jotsy]

The question I have is would it be able to adjust dwell/psi fast enough to maintain a desireable ROF

yea, thats my main concern too.

it could be set up so that only one pulse is sent from the chrono (or laser) a set amount of time after the trigger is pulled. the pulse is used to measure the distance down the barrel. so using the predetermined time, and the distance measured you can get the speed at that time.

also, having the chrono look down the barrel means it could also potentially be used to detect barrel breaks.

and another bonus would be that you can still use your regular barrels since you don't need a special barrel with a sensor in it.

[magman007]

ok, so would it weigh the balls? would it detect the diameter? it just wont work man, not in this current stage in painrball, there are too many variables to make it work. paint ia too in consistent, as are regulators, not to mention weather, wiind, moisture, and temperature. it isnt going to work.

[grEnAlEins]

ok, so would it weigh the balls? would it detect the diameter? it just wont work man, not in this current stage in painrball, there are too many variables to make it work. paint ia too in consistent, as are regulators, not to mention weather, wiind, moisture, and temperature. it isnt going to work.
with the exception of hardware flaws (eg reg and paint inconsistancies) no other variables should matter. The temp, humidity, wind, etc would be a constant as there would be no radical changes from shot to shot. As far as ball size and weight, this should not much matter as the differences are fairly minute so long as you shoot the same batch of paint. Plus you would shoot a lot of paint, so couldn't you just plan for the "middleground" due to the law of averages and law of large numbers? The paint would average out in size, weight, etc, and it would be close to the mean values due to a large sample (2000 rounds minimum, at least that is my minimum for a day of play). Maybe you could mass the 2000 balls and find the average mass, and input it using a similar feature to the Pred AFA system. The same could be done with bore size, have the average size printed on boxes from batch "Y" by the manufacturer. Then everything will be accounted for enough for good consistancy, right? So the only hardware flaw that might cause a problem is reg psi. Just have that be a manual adjustment and have the chip adjust dweell. The laws of averages and large numbers will apply to the reg psi too, as there will be a high number of cycles, so there will be an average pressure. The dwell can be adjusted via chip to account for the mean psi value. This should work unless I have made a gross error in application or understanding of the afforemantioned (sp?) laws. Someone please correct me if I am wrong.

Nick

[buzzboy]

I saw on one of my other, nonpaintball, forums that a guy had made his own chrony that used eyes set an exact distance from one another. It would be possible then to mount them in two sets of ports so they may read the speed of the paintball. Only problem then would be busted balls in the barrel.

[punkncat]

The history article you posted was a pretty good (and lengthy) read. Although I did find a few inconsistancies.....are we truly to belive that the regualtor on an HPA tank is what makes it more consistant than CO2.......discuss?

/hijack

[grEnAlEins]

I saw on one of my other, nonpaintball, forums that a guy had made his own chrony that used eyes set an exact distance from one another. It would be possible then to mount them in two sets of ports so they may read the speed of the paintball. Only problem then would be busted balls in the barrel.
but the idea is to "read" velocity before the next ball is ready for launch and leave time for adjustment. This method will work, but will it work in time for the next shot allowing time for dwell adjustment? I do not know, merely posing a question.


are we truly to belive that the regualtor on an HPA tank is what makes it more consistant than CO2.......discuss?
Sure! People believe dumber stuff: Closed bolt is better than open bolt, but SFT is a revolutionary, never-before-seen, supreme technological breakthrough. CO2 will dissolve your agg-type-gats. Mags are ultra-heavy blenders. Rifleing and spin increase accuracy. Twist-lock is gay. Mags are for F**s. Low pressure is better than high pressure. My shocker needs an LPR. Warps break paint. The Nitro tank will kill us all, TK and team Nitro are MADMEN!!!! And my personal favorite, "Name one thing TK and/or Airgun has done for paintball" ~the VP of my school paintball club to which I no longer belong. Must I go on... :rofl:

And regulated anti-syphoned CO2 is fine for most applications. This article predates OMFG Mode and uncapped hard ramping used with high feed rate force feed hoppers, so the minor inconsistancies at the ROF of a mech semi are negligable for the average rec user.

[magman007]

with the exception of hardware flaws (eg reg and paint inconsistancies) no other variables should matter. The temp, humidity, wind, etc would be a constant as there would be no radical changes from shot to shot. As far as ball size and weight, this should not much matter as the differences are fairly minute so long as you shoot the same batch of paint. Plus you would shoot a lot of paint, so couldn't you just plan for the "middleground" due to the law of averages and law of large numbers? The paint would average out in size, weight, etc, and it would be close to the mean values due to a large sample (2000 rounds minimum, at least that is my minimum for a day of play). Maybe you could mass the 2000 balls and find the average mass, and input it using a similar feature to the Pred AFA system. The same could be done with bore size, have the average size printed on boxes from batch "Y" by the manufacturer. Then everything will be accounted for enough for good consistancy, right? So the only hardware flaw that might cause a problem is reg psi. Just have that be a manual adjustment and have the chip adjust dweell. The laws of averages and large numbers will apply to the reg psi too, as there will be a high number of cycles, so there will be an average pressure. The dwell can be adjusted via chip to account for the mean psi value. This should work unless I have made a gross error in application or understanding of the afforemantioned (sp?) laws. Someone please correct me if I am wrong.

Nick


then, if you are going through all of that trouble, why is this system even needed? we play the law of averages now, set your gun in the beginning of the day, and check it ever so often and adjust as needed.

The point is that if the ball size and weight is changing, than the marker is still going to shoot a bigger bore ball in a smaller bore barrel faster than the averaged sized ball that we are basing this idea on, and a smaller ball is still going to shoot slower, no matter what the in gun chrono decides it needs to be at. also, it will still be a passive system, so you would see something along the lines of ball 1 shoots 290, user wants 295. Gun adjusts. Slightly swolen ball falls into the breach, and user is now shooting 297, gun re adjusts, and a smaller ball falls into the breach, user is now shooting 293. It would still be just as inconsistent.

[grEnAlEins]

then, if you are going through all of that trouble, why is this system even needed? we play the law of averages now, set your gun in the beginning of the day, and check it ever so often and adjust as needed.

The point is that if the ball size and weight is changing, than the marker is still going to shoot a bigger bore ball in a smaller bore barrel faster than the averaged sized ball that we are basing this idea on, and a smaller ball is still going to shoot slower, no matter what the in gun chrono decides it needs to be at. also, it will still be a passive system, so you would see something along the lines of ball 1 shoots 290, user wants 295. Gun adjusts. Slightly swolen ball falls into the breach, and user is now shooting 297, gun re adjusts, and a smaller ball falls into the breach, user is now shooting 293. It would still be just as inconsistent.
Fair enough. If we were to have the chrono not adjust for every shot, but instead "observe" several shots before an adjustment is made, then could it not be programed to automatically dispose of data from these outliers and adjust based on the average. The only problem with is that it would require a large sample set before you play, and I don't wanna shoot 500 balls at the chrono-station so that my gun can learn what the average ball that I am using on a given day is like as far as velocity at pressure "X" with a dwell seting of "Y" and adjust. This would probably be a multi step process too, so it waste a lot of paint and cash, but I bet it would work.

I am not saying that this system would be great, or even better than how things are now. I am merely saying that this could work, and probably do so fairly decently. The only problem that I can see is mentioned above, and that is wasting paint trying to create a large, random, sample of balls before you actually start playing. Personally I do not think I would use this sytem for this reason, and the fact that it would most likely be expensive. But I bet it is possible to have it on a marker and function well.

[magman007]

it is a system that would work, there is no argument there, it just isnt feasable. and, once the temperature rises throughout the day, the gun would be re adjusting its self. also, if we are playing with dwell, the marker could put its self into the point where it isnt performing to its maximum potential. also to whoever suggested using the spool valve, adjusting the dwell isnt going to do much on a spool valve, all of maybe 5 fps from 18 to say 40 ms.

[sunyjim]

The history article you posted was a pretty good (and lengthy) read. Although I did find a few inconsistancies.....are we truly to belive that the regualtor on an HPA tank is what makes it more consistant than CO2.......discuss?

/hijack

Yes the regulator is exactly what makes it more consistant.
Sure CO2 fluctuates by temperature. From day to day, the temperature is different so the velocity needs to be adjusted. But it is a very stable self regulating gas.
A bottle filled with a mixture of liquid and gas CO2 (normal fill), when the valve is opened the tank will put out a reasonably constant pressure over an extended period of time. Roughly 800psi depending on temperature. but assuming the temperature remains constant, the pressure remains constant until the tank is out of liquid CO2.
Compare that to a N2 cylinder, 4500psi, open the valve and the pressure immediatly begins to drop and continues dropping on essentially a straight line until the tank is empty.

So imagine if you were trying to make a marker that would run on 4500 psi, an air tank would be useless, the pressure would very quickly drop out of useful range and the marker wouldn't function. But markers don't, they run on a much lower pressure (ususally 800psi because CO2 was the gas used by the designers) so a regulator was designed to reduce tank pressure to operating pressure. It accepts whatever the tank is outputting and gives a set, much lower operating pressure amount, and continues to do so until the tank runs below the operating pressure. The paintball regulator is essentially a device that is designed to replicate what CO2 does on it's own.
So opening the valve on that same air tank now with a regulator, the tank would now put out a consistant pressure until it ran below that operating pressure.

True, trying to play speedball at 20bps with even regulated CO2 is going to give some trouble unless the marker is running a very low pressure like an Airstar Nova (ran on 95psi with a built in regulator), the co2 can't boil into gas fast enough to keep up with a standard 800 psi marker firing over I'm guessing 12 bps.

But say two identical markers with identical built in regs. One with Co2, the other a N2 tank directly connected with no tank regulator. Then fired at an equal 5 bps over a chronograph, I would be willing to bet that the CO2 out performs the N2 for shot to shot consistancy hands down.
The Co2 is essentially dual regulated, the tank already puts out a reasonably constant pressure of 800psi, where the N2 puts out an always changing, falling pressure. The regulator just refines the pressure of the co2, but has to work very hard to maintain a constant with the falling input pressure of the N2

Sorry the reply is so long. :eek: :)