# Smartphone Chrony Setup Tutorial



## M.J

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.









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.









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:









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









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"









Next is "Device to muzzle": 96"









Then, "Device to pellet path: 6"









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.









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









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


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## Henry the Hermit

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!


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## ZorroSlinger

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!


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## Dayhiker

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.


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## Henry the Hermit

Dayhiker said:


> 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.


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## Tube_Shooter

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.


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## M.J

Tube_Shooter said:


> 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.


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## Tube_Shooter

M_J said:


> 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.[/quote]
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


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## M.J

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


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## Henry the Hermit

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.


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## lightgeoduck

Great job with this MJ. VERY useful!!

I will have to try this soon


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## Adirondack Kyle

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.


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## Guest

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.


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## Guest

OldSpookASA said:


> 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 =(


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## Adirondack Kyle

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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## Adirondack Kyle

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.


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## Guest

adarondack kyle said:


> 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 =)


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## Adirondack Kyle

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.


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## M.J

adarondack kyle said:


> 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


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## lightgeoduck

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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## lightgeoduck

Henry in Panama said:


> 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


thanks for the pic and great idea to on doing comparitive readings. I was wondering how I was going to ensure that I was doing the same thing for both set ups, and now I know I can get two readings from each individual shot.


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## All Buns Glazing

Took me a while to find it until I searched for "chrono" instead of "chrony connect" lol.


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## Adirondack Kyle

Thanks , either way, good to know. Soon as the weather gets better, i can work on those speed badges!!


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## The Gopher

maybe a stupid question, would the "muzzle" be the slingshot tips or the anchor point or somewhere in between?


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## M.J

The Gopher said:


> maybe a stupid question, would the "muzzle" be the slingshot tips or the anchor point or somewhere in between?


As far as the app is concerned, the muzzle is the first sound it hears. That's why I shoot through the paper and into the target. The "muzzle to target" distance is from the front of the piece of paper to the target.

Does that help?


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## ZorroSlinger

Quick look on net and found this. I don't recall if anyone mentioned 'Shot Muse' for iphones ....

http://bulletin.accurateshooter.com/2011/10/new-iphone-shooters-app-has-multiple-functions/

It's not free but still budget cost-effective compared to dedicated chrono device. I'm not iphone or apple products user and don't know if they offer trial of app for testing.


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## Henry the Hermit

lightgeoduck said:


> 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


Sorry I missed this earlier. I have been unable to get consistent readings with the Apple apps I've tried and the results were difficult to interpret.


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## jsbelljr83

M_J, thanks a MILLION for posting this info!! I downloaded the app for my Driod and rigged up a box with two openings to shoot though but never got the app dialed in for distance, bearing weight, etc. Depending on how much snow we get tonight I will set my phone up Sun and test it out. Thanks again!!!!! :woot:


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## B.P.R

Whats the ammo weight of a 9mm steel ball? 

You americans are talking in jibberish with your 3/8" haha


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## Charles

blue pocket rocket said:


> Whats the ammo weight of a 9mm steel ball? You americans are talking in jibberish with your 3/8" haha


http://americandad.biz/chromechart.htm

https://www.google.ca/search?q=convert+inches+to+cm&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-USfficial&client=firefox-a

https://www.google.ca/search?q=convert+cm+to+inches&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-USfficial&client=firefox-a

A 3/8 inch diameter sphere is .9525 cm. With all due respect, surely you did not need to ask this question if you have internet access. 

Cheers .... Charles


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## Joseph

Oh wow, this is so cool. I'm not going to be able to try it until I go home so not for another 6 weeks by I am really excited about trying out some of my setups.


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## Arturito

I have done some slomo video/audio research, the problem with the android app is that was made for airguns not for slingshots, which has a different noise pattern than airguns, slingshot noise is composed by two bursts of noise, first burst is made by rubber retraction/acceleration and the second burst occurs when the rubber start entangling dissipating the remanding (not used) energy slap.









1 is the release time

2 is the first burst of noise due to retraction/acceleration

3 is the time of minimum noise, rubber is at a rubber length behind the fork, this is the point where ammo separation starts.

4 is the residual energy dissipation, rubber slows and entangles/slaps.

5 is the time of target hit

so the net time should be calculated between 3 and 5 (adding the relaxed rubber length to distance).

I've checked with the android app and it seems to use time at 4 at the peak to calculate speed, that's why it gives more speed than a crony, the correct time is at point 3 adding a band length to target distance.

crony's gives a "instantaneous speed" while audio calculus gives the "mean speed" to target (crony doesn't take account of some little friction with air).

The 2 paper method introduces a little slowness because ammo is transferring some energy to the first paper (if is too thick)

Cheers

Arturo


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## M.J

That's why I shoot through newsprint. Loud enough to register the sound but thin enough that they don't slow the ammo to any meaningful degree.


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## Henry the Hermit

M_J said:


> That's why I shoot through newsprint. Loud enough to register the sound but thin enough that they don't slow the ammo to any meaningful degree.


And that's why your method is the approved one for SSF 300 Club. It works.


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## jokso

I got me a package from dankung, 1842 and flat latex so I played a little today....
With flats, double per side, 22mm to 11mm taper 8.55mm lead, results were between 236-265fps, on more than 10 shots and slapping was horrible. So I made me new double pseudo 1842, tested it few minutes a go and I'm still stunned :blink:







These are first 3 shots, fourth was 240 and last 2 316 and 324 :hmm:

I was shooting exactly 5m away, without paper just band slap...it is to good to be true so I shot 4 more shots and saved mp3 for audacity but waves are different than before, every shot has 3 major spikes(instead of 2 like before)...I posted link to mp3 file if anyone wants to take a look

https://dl.dropboxusercontent.com/u/51687567/20130602_221555%20(1).mp3

p.s.

There is something wrog with dropbox so i uploaded here

http://depositfiles.com/files/loplxxl11


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## M.J

Like Henry and I have said, the only way to get reliable results with this app is to shoot through one piece of paper and into something else that will make a noise when hit. Tubes especially don't make enough noise on release to register.
I don't even use the big box anymore, just a small piece of paper on a stick mounted up in the firing line. You said you were shooting from "exactly 5m" but is that where your feet were or where your slingshot was? It matters to the app which is why you need the first paper since it can be set at an exact distance.
If you use the app the way I described then it's very reliable, if you do it any other way it's pretty much useless.


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## ash

When I first tried the app, it was just using the sound of the bands and mid 300s were common, but the results were very inconsistent, much like yours. As soon as I started using a paper first noise producer, the results stabilised in the mid-high 200s... much more realistic figures.

Now that I have a genuinely fast setup, I'm finding it difficult to get over 360fps. I can shoot ammo in four different sizes at 350fps again and again, but rarely higher, even with the small ones and even when it sounds faster. I'm wondering if there are other complications from band noise and rebound noise that need to be accounted for. I might look at a double sheet noise producer and different app sensitivity or placement.


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## All Buns Glazing

Yeah, as MJ said. I've done a lot of experimentation with this app, and the only way to get consistent results is by shooting through paper, into paper. I shoot from a couple of meters away from the paper when using flatbands so it doesn't register a false muzzle shot.


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## jokso

Oh but my tubes produce more than enough noise, app is registering it every time. The problem is it produces 2 large sound spikes....couldn't use paper, didnt have where to hang it, I'll try to think of something later.


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## Imperial

ash said:


> When I first tried the app, it was just using the sound of the bands and mid 300s were common, but the results were very inconsistent, much like yours. As soon as I started using a paper first noise producer, the results stabilised in the mid-high 200s... much more realistic figures.
> 
> Now that I have a genuinely fast setup, I'm finding it difficult to get over 360fps. I can shoot ammo in four different sizes at 350fps again and again, but rarely higher, even with the small ones and even when it sounds faster. I'm wondering if there are other complications from band noise and rebound noise that need to be accounted for. I might look at a double sheet noise producer and different app sensitivity or placement.


is 350 the top of mark for the app ?


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## jokso

It can't be because its made for air rifles, and thay go over 1000fps


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## All Buns Glazing

Imp, I would assume certainly not - it's designed for rifle fire.

The problem with using the band slap noise for the muzzle shot, you need to know exactly what point the bands make that slapping noise. Half a foot is a significant difference when you're talking about a projectile travelling a couple of hundred feet per second over a fraction of a second.

Here's how I did it at my old house. I recommend using a system that doesn't drive you crazy like this one did, but I managed to get the measurements fairly accurate (when the paper isn't shot to helton)


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## ash

It gave me a 381 just once and other figures over 350. I would think it tops out at 999 or more.


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## Imperial

okay guys, just asking, since it wasnt set up right. i use my phone for calls,

not as a speed gun.


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## All Buns Glazing

Priorities Imp... priorities. I remember my wife called me once during a slingshot shooting video I was making. She seemed to think she did nothing wrong.


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## Dr J

Very interesting information ! Am I to understand from all the above, that the app works ok on the iPod but not the iPhone! Or am I missing something that will make it click?


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## Arturito

if you are not going to to use the 2 paper method and avoiding "secondary" noise this application for me is useless, much better is Audacity analysis, you can obtain average speed to target, or the same 2 paper method for the iPhone, I've learned to interpret correctly the 2 bursts noise pattern of a slingshot to match very close the 2 paper method without the cumbersome of it's installation and let me know the speed of every video I record ... my 2 cents ...

Cheers

Arturo


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## Henry the Hermit

Dr J said:


> Very interesting information ! Am I to understand from all the above, that the app works ok on the iPod but not the iPhone! Or am I missing something that will make it click?


The app does not work on Apple. It works only on Android devices.


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## JUSTJOB

I know I am responding to an older thread. Great info too in this thread!

I did however notice that Apple now offers the app for Chrono Connect too now.

So are we allowed to use the Apple version of Chrono Connect also? Or only the Android version of Chrono Connect?


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## All Buns Glazing

If it's anything like their maps, I'd say no! ;-) (kidding, I'm sure it's the same. Try it out!)


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## One Shot-Corey

i would think if its the same app it should be ok but u might want to pm henry and ask him


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## Henry the Hermit

I don't have an iPhone, so can't test it. I do have an iPod and will try to give the app a go later this week.


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## JUSTJOB

Thanks Henry!


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## SzBalogh

BC for lead round balls: 0.38" -> ~0.05, 0.45" -> ~0.07. I think it makes not much difference on the low distances we are using the app.


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## gunslingster

I didn't even know that you could get this app, so yet another thing I have learned on this helpful forum.


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## ukj

Anyone have current info for ios
audio app?
If so exact name so can search apple app store.
Getting curious sometimes as to
speed parameters for testing different
setups.
THX for your info if you know!
I did sesrch but must not have used correct find words?
ukj


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