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Chronograph

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Chronograph

Unread postAuthor: natas » Sat Apr 21, 2012 3:59 pm

I see a need for a chronograph soon. And have tried to find a crony thread inside here with no luck.
ill primarily use it for potatoes.
so I am trying to find out whats hot or not :-)


i a crony like this ok ??

http://www.ebay.com/itm/Shooting-Chrony-Gamma-Chronograph-w-Ballistic-Printer-/170826214359?pt=LH_DefaultDomain_0&hash=item27c6092bd7#ht_1313wt_759
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Unread postAuthor: Fnord » Sat Apr 21, 2012 4:35 pm

You probably won't need the printer unless you're doing a lot of serious testing. Most of us just use normal f1-chronys.

If you'd prefer your readout in m/s, go for an M1 variant.

If you're using potatoes, use the money you saved without the printer and get materials for some heavy-duty shielding.
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Unread postAuthor: jimmy101 » Sat Apr 21, 2012 5:28 pm

There are many threads on shooting chronographs. Though to find them you need to use something like "chrony" not "crony" :D

A recent one:
http://www.spudfiles.com/forums/shootin ... 23922.html

If you only need to do a few measurements and don't want to spend the $60 or so for a chrony you can do it with a laptop and less than $5 in parts.
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Unread postAuthor: wyz2285 » Sun Apr 22, 2012 5:53 am

About that less than 5$ part+pc, I haven't been able to put it to work yet :roll:
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CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Unread postAuthor: jimmy101 » Sun Apr 22, 2012 11:34 am

wyz2285 wrote:About that less than 5$ part+pc, I haven't been able to put it to work yet :roll:
Laptop + microphone (google for a copy of "SoftChrono")

A pair of photo transistors (or even CdS cells) from RadioShack + sub-mini stereo plug + wire + random bits of PVC. (http://www.inpharmix.com/jps/Jims_chrono.html)

Still having problem with no voltage from your MIC intput? [/url]
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Unread postAuthor: Technician1002 » Sun Apr 22, 2012 11:59 am

Add a copy of Audacity to record and measure the event as an alternative to SoftChrono, A ruler or tape measure to set the distance between the sensors. SoftChrno is in Beta. Audacity is no longer Beta software and is multi platform. Windows, Mac, and Linux versions are available.

Can't forget the obvious.

Oh, and shoot in the daytime with lots of light.
Photocells don't work in the dark due to the lack of shadows. :D
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Unread postAuthor: natas » Sun Apr 22, 2012 12:42 pm

thnx alot for the tips :D
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Unread postAuthor: wyz2285 » Sun Apr 22, 2012 2:06 pm

Still having problem with no voltage from your MIC intput?

yes, but I decided to looking for some new phototransistors :roll:
Oh, will SoftChrono work for a hybrid?
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CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Unread postAuthor: RJB INDUSTRIES » Sun Apr 22, 2012 5:02 pm

Some piece like this.....


RJB INDUSTRIES
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Unread postAuthor: mark.f » Sun Apr 22, 2012 5:38 pm

RJB INDUSTRIES wrote:Some piece like this.....


RJB INDUSTRIES


Only one photosensor and relatively expensive compared to Radioshack parts, though.
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Unread postAuthor: RJB INDUSTRIES » Mon Apr 23, 2012 1:49 am

Maybe....


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Unread postAuthor: wyz2285 » Mon Apr 23, 2012 10:37 am

Anybody please answer me: will SoftChrono work for a 20x hybrid? I have a chronograph but after MrC shotted his, I don´t want to risc my...
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CpTn_lAw wrote::D "yay, me wanna make big multishot pnoob with 1000 psi foot pump compressor using diamond as main material. Do you think wet bread make good sealant? " :D
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Unread postAuthor: jackssmirkingrevenge » Mon Apr 23, 2012 11:09 am

wyz2285 wrote:I have a chronograph but after MrC shotted his, I don´t want to risc my...


MrC shotted his because he didn't take the right precautions ;)
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Unread postAuthor: jimmy101 » Mon Apr 23, 2012 8:40 pm

What Technician said, you really only need something like Audacity. Softchrono has some wiz bang features but it is not required.

Just record the sound of the shot and extract the "bang" to "bink" time from the recording in Audacity. It'll work fine for any launcher, just increase the distance for launchers with very high muzzle velocities.

It is easiest to extract the signal peaks if you shoot outdoors in an environment away from walls, buildings etc., anything that gives an echo makes the recording much harder to interpret.

If you measure the distance from the muzzle to the MIC and from the target to the MIC you can correct for the speed of sound without having to put the laptop in harms way.
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Unread postAuthor: Technician1002 » Mon Apr 23, 2012 9:27 pm

jimmy101 wrote:If you measure the distance from the muzzle to the MIC and from the target to the MIC you can correct for the speed of sound without having to put the laptop in harms way.


The simple solution is to place the mic the same distance from the muzzle and target, either off to the side or halfway between. Another option is 2 mics, one at the launch and one at the target.
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