simple diy ballistic chronograph

[farcticox1]

Anybody tried making one of these, does it actually work ?

[mark.f]

Of course.

[farcticox1]

noyce

[jimmy101]

I think that is a bit more complex than needed. You don't need the IR LEDs since ambient light is usually enough. You can use a slice of a pipe to mount the phototransitors so that ambient light can get to the detectors. Since you don't need the LEDs you don't need to use the USB port.
http://www.inpharmix.com/jps/Jims_chrono.html

[farcticox1]

it's so simple it will nearly build itself

[D_Hall]

Back when I played paintball you could BUY systems that worked exactly as described in this thread. And they were pretty cheap.

[farcticox1]

BUY stuff ? I think I'm in the wrong forum

[mark.f]

BUY stuff ? I think I'm in the wrong forum

Back when...

I don't think you can buy them anymore so you're still on the right forum.

[farcticox1]

close call, back to making stuff for nothing

[jimmy101]

If you are really cheap (raises hand) you can just use your phone (or laptop or tape recorder or ...) to record the sound of your gun firing at a piece of wood a measured distance from the barrel (watch out for the ricochet). The recording will have a strong signal when the ammo "uncorks" the barrel followed shortly thereafter by the sound of it hitting the target.

[mark.f]

When I made mine I had all the parts lying around (including the Arduino). But starting from complete scratch would require an arduino (~$40), any laptop capable of running Arduino CC (which is any laptop made in the last 20 years capable of running debian: ~$50 - max not defined), and some IR LED's and phototransistors ($10).

Jimmy's method linked on his site is probably your best bet if you have a computer with a sound card (highly likely, includes integrated audio... sampling rates will obviously differ). Although, the software recommendations could be updated a little (*hint hint* , Audacity can do most of the things mentioned on the page at least on Debian).

If you're transitioning to Larda-level velocities, or you want something dead simple, you can build a break-wire chronograph, which is exactly what it sounds like (a wire carrying a sense current which when broken triggers either the "STOP" or "START" function of your "timer", which could also be a sound card).

[jimmy101]

Jimmy's method linked on his site is probably your best bet if you have a computer with a sound card (highly likely, includes integrated audio... sampling rates will obviously differ). Although, the software recommendations could be updated a little (*hint hint* , Audacity can do most of the things mentioned on the page at least on Debian).

Actually, the page does say:

Note Added 16 October 2007.
I no longer use SoundRecorder or AudioEdit. The best freeware program I've found for recording and displaying sound files is Audacity.

[mark.f]

Actually, the page does say:

Note Added 16 October 2007.
I no longer use SoundRecorder or AudioEdit. The best freeware program I've found for recording and displaying sound files is Audacity.

My mistake, nice catch.

[Xamllew]

Has anyone here tried any of the various chrony smartphone apps? I have one called Chrono Connect but have yet to try it.

[mark.f]

If I'm reading it right it works like a normal "microphone chronograph" which can be done without spending $3.85 to unlock the "Pro version". It's handy to have available on your phone, but as mentioned, the technique is really simple and can be done with few special "tools" (software).