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Smartphone Chrony Setup Tutorial


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#1 M.J

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Posted 27 January 2013 - 10:49 AM


Ok, here goes: my attempt at giving you all the info you need to get accurate, consistent readings from your Android smartphone chrony. Keep in mind, the app from ChronyConnect only works on Android phones. Sorry 'bout that but we're not going to have an "Apple vs Android" debate in this thread and all comments along those lines will be deleted.

Let's get the test envrionment set up first. You need a target that will make some pretty good noise when hit. A good thick piece of cardboard will work fine, a metal lid or somethinhg would work as well. You also need something to shoot through. This app is meant for airguns and needs that first "muzzle report" to time the shot and generate FPS numbers. I have a stand set up with a piece of newsprint to shoot through. It doesn't slow the shot down and makes enough of a "crack" to register. I stand right behind the paper and shoot through it into the target. Target and stand are 16' (192") apart.

Chrony 11.JPG

 

My phone is set on a tripod halfway between the newspaper and the target and as high up as I dare to set it. One of the measurements you'll need is "Device to pellet path", that's how close the ball will pass over the phone. It's about 6" in this case.

Chrony 13.JPG

 

On with it, then! FIrst thing's first, go to the Google Play store and search for Chrony Connect. Get the free version first and then go back for the paid one (like $3) if it works for you.

When you first open the app it will look like this:

Chrony1.JPG

 

Tap the "Menu" button indicated by my thumb in the pic and you will get this menu:

Chrony 3.JPG

 

This lets you set up all your distances and ammo weight (for power readings). Start with distance in the "Target Options" menu. Distances can be set in a variety of different units of measure, I'm using inches.

First up "Muzzle to target": 192"

Chrony 4.JPG

 

Next is "Device to muzzle": 96"

Chrony 5.JPG

Then, "Device to pellet path: 6"

Chrony 7.JPG

After that you can go to the "Projectile Options" menu and input your ammo weight. This will give you stats for the energy in the shot in ft/lb. You can Google "steel bearing weight" for a chart, this pic has several sizes on it, as well. Weight can be in grains or grams, I'm using grams.

Chrony 10.JPG

After your all set you take your shots (3 at a time for the free version), check and repeat :)

Chrony 14.JPG

If you have any more questions or if I've left anything out please don't hesitate to ask!

 

 

 

 

 

 

Attached Thumbnails

  • Chrony 2.JPG
  • Chrony 8.JPG
  • Chrony 9.JPG
  • Chrony 12.JPG

Edited by M_J, 27 January 2013 - 10:50 AM.


#2 Henry in Panama

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Posted 27 January 2013 - 11:16 AM

Great job, clear and concise. Later this afternoon, I'll borrow the wife's phone, follow the tutorial and see how the app compares to my Chrony. Thanks!



#3 ZorroSlinger

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Posted 27 January 2013 - 01:21 PM

Just beginning my renewed interests in slingshots and I was not going to get into this deeper technical aspects of chronograph speed measurements, however as a gadgeteer, tinkerer & DIY type, this looks intriguing & fun :)
 
So the muzzle measurement point is at the newspaper sheet, then you measure from sheet to target. Hmmmm, I do not trust my inconsistent marksmanship skills. Just in case, if I were to pursue this chrony adventure, I would maybe put some kind of quick & dirty cardboard or styrofoam shield around the smartphone to protect it, especially since I would be sort-of shooting blind through that box & newspaper sheet. Good tutorial, even a beginner can understand! 


#4 Dayhiker

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Posted 27 January 2013 - 01:37 PM

Thanks M_J.  I don't have an android, but I think Henry said they have that app for the Ipod touch, which I do have.  Even if this setup isn't real accurate, it's still a good way to compare different band/ammo combinations to see how much faster one ammo shoots over another.

Great video.



#5 Henry in Panama

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Posted 27 January 2013 - 03:00 PM

Thanks M_J.  I don't have an android, but I think Henry said they have that app for the Ipod touch, which I do have.  Even if this setup isn't real accurate, it's still a good way to compare different band/ammo combinations to see how much faster one ammo shoots over another.

Great video.

 

Let me know how you make out with the iPod Touch app. I couldn't get consistent readings with mine.



#6 Tube_Shooter

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Posted 27 January 2013 - 03:38 PM

Can someone try this please? Hold or tape a piece of paper on the fork,in the flight path.It may work and if so you will not be blind shooting may give confidence to some if it works.

#7 M.J

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Posted 27 January 2013 - 03:44 PM

Can someone try this please? Hold or tape a piece of paper on the fork,in the flight path.It may work and if so you will not be blind shooting may give confidence to some if it works.

You can make a stand for the paper that is much smaller than what I have and that you wouldn't have any trouble seeing around. I threw that together in a hurry to get the initial review and the tutorial up.

#8 Tube_Shooter

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Posted 27 January 2013 - 03:54 PM

Can someone try this please? Hold or tape a piece of paper on the fork,in the flight path.It may work and if so you will not be blind shooting may give confidence to some if it works.

You can make a stand for the paper that is much smaller than what I have and that you wouldn't have any trouble seeing around. I threw that together in a hurry to get the initial review and the tutorial up.

Yes of cause you can,thanks MJ BTW did you find the BC correct for 3/8 steel? Or will this have to be tweaked as more info comes in? Great job on this it will help many

#9 M.J

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Posted 27 January 2013 - 05:04 PM

I didn't mess with the ballistic coefficient, too much for me to figure out :)

#10 Henry in Panama

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Posted 27 January 2013 - 05:41 PM

I just finished setting up step-by-step by your tutorial, and made enough shots to verify that the Android Chrono Connect app is accurate enough for membership in the SSF 300 Club. I may have been off a tiny bit in my setup because I did all the measurements alone. The Android was consistently a few fps faster than my Chrony by about 2%. Close enough!

 

Here's what my setup looks like. The sheet of paper attached to the Chrony rods is to generate a sound for the Android and the target is a cardboard box. The sheet of paper and the box are 192 inches (16 feet) apart. The phone is on the table half-way between the sheet and the target.

 

android-test.jpg



#11 lightgeoduck

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Posted 28 January 2013 - 07:18 AM

Great job with this MJ. VERY useful!!

I will have to try this soon

#12 Adirondack Kyle

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Posted 28 January 2013 - 10:44 AM

Bill Hayes did a vid on the app as well, his first shot was right on!! The next two were a few fps off. The slap of the bands were loud enough for the app to pick it up , no paper, just have to use wood or something loud to set your target in front of.
I think it works better in an open area, also, i believe your phone quality has something to do with it. More sensitive the audio, the better.
As long as you calibrate the app every time you shoot, and measure your distances carefully, this app is very reliable.

#13 Guest_OldSpookASA_*

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Posted 28 January 2013 - 06:46 PM

The one observation I would make here is this. It seems to me that the phone could be anywhere along the path between the first target and the second target because sound travels at a constant velocity. What I am trying to say is that the sum of the sound travel time between the first shot and second shot is always equal to the sound travel time between the first target and second target. That would in fact be true even if the phone was not between the two targets. The reason I bring this up is that phones which get shot are probably going to quit working. You should test with the phone just behind and below the first (newspaper) target. I believe you will get the same accuracy that way. Also the distance below the pellet path will probably be more consistent if the phone is closer to the shooter. Just random thoughts.

#14 Guest_OldSpookASA_*

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Posted 28 January 2013 - 06:51 PM

The one observation I would make here is this. It seems to me that the phone could be anywhere along the path between the first target and the second target because sound travels at a constant velocity. What I am trying to say is that the sum of the sound travel time between the first shot and second shot is always equal to the sound travel time between the first target and second target. That would in fact be true even if the phone was not between the two targets. The reason I bring this up is that phones which get shot are probably going to quit working. You should test with the phone just behind and below the first (newspaper) target. I believe you will get the same accuracy that way. Also the distance below the pellet path will probably be more consistent if the phone is closer to the shooter. Just random thoughts.
In the above I should have said "the sum of the sound travel time between the first hit and second hit". The phone does not know where it is in the path. But it does need to know how far off the path it is because that changes the total length of the path the sound travels... I'm not explaining myself well =(

Edited by OldSpookASA, 28 January 2013 - 06:52 PM.


#15 Adirondack Kyle

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Posted 28 January 2013 - 07:07 PM

It does, that's one of the settings , you have to enter, muzzle to target. Device to muzzle,device to pellet path,
You are correct, but this will factor how far off the path you are as well.

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#16 Adirondack Kyle

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Posted 28 January 2013 - 07:17 PM

And yes, it will work better closer to the shooter, and, no need to shoot through something first like newspaper. The band slaps should set it off. Bill Hayes just did a vid on this.

#17 Guest_OldSpookASA_*

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Posted 28 January 2013 - 07:21 PM

And yes, it will work better closer to the shooter, and, no need to shoot through something first like newspaper. The band slaps should set it off. Bill Hayes just did a vid on this.
Welp! That certainly beats shooting your phone or your chrony. I wish we had discovered this a week before instead of a week after I bought a new chrony =)

#18 Adirondack Kyle

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Posted 28 January 2013 - 07:23 PM

Sorry to re post too much, but i think that if you wanna test your bandsets, like me, or test diff types of ammo and elastics, then this is perfect, but i would understand if the forum wont allow them for speed badges, just for the fact that n order for it to be right on, your measurements have to be perfect, hard to verify, even a few steps to the side can throw your numbers off.

#19 M.J

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Posted 28 January 2013 - 07:47 PM

And yes, it will work better closer to the shooter, and, no need to shoot through something first like newspaper. The band slaps should set it off. Bill Hayes just did a vid on this.
I'm going to keep shooting through paper because I believe it cuts down on variables and gives a better chance at consistent readings. For one, the looped tubes I often use produce virtually no slap and for another, by the time the bands make that sound the ammo is already long gone.
Also, Henry has approved this app for the Speed Club :)

#20 lightgeoduck

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Posted 28 January 2013 - 07:56 PM

Yeah the paper seems like you would get a consistant muzzle noise each time, not all of my set ups make band slaps, in fact, none of my butterfly shooting set ups make a band slap since I am afraid a set up that would would give the opportunity for a hand slap.

 

 

My wife is the one with the android, and I can't seem to find the apple app.. Henry?

 

 

LGD






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