Homemade chronograph

Antonio · Thu Jul 24, 2008 4:38 pm

Wombat wrote:Something like this was posted once before on nerfhaven, here's a link-

http://nerfhaven.com/forums/index.php?s ... hronograph

This setup only uses one microphone so is easier to setup. Moving the mic in the middle or using the time correction (speed of sound>) it achievable with one mic. Why use two...?

Sticky_Tape · Fri Jul 25, 2008 7:52 am

Does the slash in distance/time=speed?

jimmy101 · Fri Jul 25, 2008 1:20 pm

Sticky_Tape wrote:Does the slash in distance/time=speed?

Yes. Divide the distance in feet from the muzzle to the target by the time between the two peaks in the recording.

The distance can be pretty much whatever you want, you just need to know what it actually is to a reasonable degree of accuracy.

Sticky_Tape · Fri Jul 25, 2008 2:18 pm

Thanks Jim it was confusing.

Antonio · Fri Jul 25, 2008 3:17 pm

Sticky_Tape wrote:Thanks Jim it was confusing.

lol that was the only dividing sign I could find. but yeah its basic if you just put the mic in the middle.

ross_brigoli · Tue Dec 16, 2008 12:35 pm

Check this out. No need to manually compute.

Here's my home made chrono. http://briggs69.blogspot.com/2008/11/pc ... hrono.html

starman · Tue Dec 16, 2008 12:51 pm

Nice work there Ross. Too bad parallel ports have all but disappeared on modern computers.

brplatz · Tue Dec 16, 2008 12:54 pm

Actually i did this too, possibly before you. Here
I used a mic input for the data which is still there on most computers nowadays.

jammerjam · Thu Jan 08, 2009 9:52 pm

but I have a question for those who are in the know.

I recently purchased a new rifle, an AGM MP-001 sniper rifle, and wanted to see what the fps was on it. I have an audio file that I took from this rifle using a piece of software called SoftChrono. Now I took the shot from 20 feet away inside with the mic, mono, at the 10 foot mark. I had a metal plate at the target spot, yeah I know... I had a lot of ricochet!, and had a really good report sound when the bb hit the plate. SoftChrono reported both fire, and target hit but it returns the FPS as being 1221 fps.......

Sorry about this post... I figured out my problem... I had my trigger levels set wrong, AND had some setting wrong.

So.. I apologize for reviving this post, but there is a really nice software based Chrono that appears to be pretty accurate. Although I don't like the results I got.. 340 fps is really low....

JAson

rp181 · Thu Jan 08, 2009 10:03 pm

brplatz, Yours is quite different, ross uses a computer to automatically get the readings. This also helps in keeping results consistent. I was recently looking for a way to interface a serial cable to a computer, but i deal with java.

Homemade chronograph

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