Homemade Chronograph

Urban Ninja · Thu Jul 06, 2006 8:27 am

Does anybody here know how to make a CHEAP chronograph? I really need one but do not want to spend a lot on one. Also I like to make alot of my equiptment my self, feeling of achievement

. I saw this on an airsoft website, but would it act as a rough guide for a spudgun? I realise spudguns fire at a much higher velocity so, what do you think?

http://www.seattleairsoft.com/modules/n ... =15&page=0.

Please tell me if you have already made one, thanks.

saladtossser · Thu Jul 06, 2006 9:42 am

oh oh i know

you need a laptop, or a modified digital sound recorder

2 sheets of thin almunium foil are being shot at

a signal is started by the breaking of the 1st foil

the signal is ended by the breaking of the 2nd foil

the length of the signal is measured on a computer using an audio editing program

frogy · Thu Jul 06, 2006 12:13 pm

BTW, this wont work with loud combustions or pneumatics unless the alluminum foil has a certain pitch when it breaks and you'd have to filter that out...

I could make one out of 4 IR LEDS, 4 IR RECIEVERS, some transistors, sone resistors, and a Printer cable probably... lol

But I'd have to make a program that'd decifer that signal getting broken when and the time between the two getting broken, and I'm not the greatest programmer so I'm not sure how it'd work....

To do what saladtosser said it's be very hard to do seeing that alluminum foil would most likely get broken from the air rushing out of your gun and the digital recorder would pick-up the shot instead of foil breaking...

WOW!! · Thu Jul 06, 2006 12:36 pm

Here is a link to make a even better chono. It is a lot easyer. I would suggest to make that one. http://home.earthlink.net/~jimsluka/Jims_chrono.html

FiveseveN · Thu Jul 06, 2006 3:32 pm

Yeah, that's the one I've been wanting to make, too. Just haven't found the time.
Besides the problems listed above, the ol' paper and mic system has a pretty serious flaw: when the projectile hits the 1st sheet of paper, it slows down. Not by much, but it's already not a scientific grade instrument, so adding tolerance is the last thing you'd wanna do.

saladtossser · Thu Jul 06, 2006 3:40 pm

frogy wrote:BTW, this wont work with loud combustions or pneumatics unless the alluminum foil has a certain pitch when it breaks and you'd have to filter that out...

what the hell r u talking about? sound has nothing to do with it... it the same idea as light but without too much electronics stuff

WOW!! · Thu Jul 06, 2006 3:52 pm

saladtossser wrote:
frogy wrote:BTW, this wont work with loud combustions or pneumatics unless the alluminum foil has a certain pitch when it breaks and you'd have to filter that out...
what the hell r u talking about? sound has nothing to do with it... it the same idea as light but without too much electronics stuff

Wtf are you talking about? If it doesent have to do with sound then read and look at the picture and tell me what the spikes all are.

Atlantis · Thu Jul 06, 2006 4:08 pm

You could make a Chronograph barrel. Have a timer start when you pull the trigger, then put a tiny off switch at the end of the barrel, when the potato hits the switch the timer will stop, cheap and simple wihtout using a computer.

You could also use 2 switches, first switch ON, second switch OFF.

saladtossser · Thu Jul 06, 2006 5:02 pm

oops, maybe i should have went there... but the aluminum foil is meant to be a conductor being broken

boilingleadbath · Thu Jul 06, 2006 8:57 pm

I know that in labratory real-bullet tests they (at least occasionaly) use a broken conductor strip for muzzle velocity tests.

Urban Ninja · Thu Jul 06, 2006 11:50 pm

Cool thanks guys, I might incorporate a few ideas and post a how to on making one. Thanks for the link.

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