Can I use smartphone slow motion video to estimate amplitude？

[EatPeach]

Hey guys.I‘m a watch repair amateur. Recently my timing machine is malfunction. Meanwhile I'm working on some scrap movement with the IOS app called timegrapher. The amplitude reading seems inaccurate and unstable.

So I've been thinking can I estimate the amplitude with the slow motion video of the balance wheel？

Is amplitude the degree of the balance wheel oscilate from A to B? Or I still have to do some calculation？

[Graziano]

Hi there not as accurate as a timing machine but it would surely give you an idea how its going , you should be getting about 250-300 degrees any more is a bonus ,yours looks like about 310 degrees .However positional error ,amplitude in different positions would be a bit more challenging . Then you've got beat error which you can't see .But I think it's ok for a general idea.  Hope this helps

Edited March 8, 2020 by Graziano

[Marc]

1 hour ago, EatPeach said:

Is amplitude the degree of the balance wheel oscilate from A to B?

Nope....

Amplitude is the angle of rotation from the balance point of rest to the furthest point it reaches from it's point of rest.

So amplitude = A to C, or B to C.

A to B is amplitude X 2.

Your video seems to show an A to B rotation of about one full turn, or 360 degrees, which equates to an amplitude (A to C or B to C) of 180 degrees.

Edited March 8, 2020 by Marc
I checked the video

[Nucejoe]

Good set up to have, specially to spot  overbaking, rebanking and in general faults in escape mech.  

[EatPeach]

22 minutes ago, Marc said:

Nope....

Amplitude is the angle of rotation from the balance point of rest to the furthest point it reaches from it's point of rest.

So amplitude = A to C, or B to C.

A to B is amplitude X 2.

Your video seems to show an A to B rotation of about one full turn, or 360 degrees, which equates to an amplitude (A to C or B to C) of 180 degrees.

So my case is about 180 amplitude?

[EatPeach]

18 minutes ago, Nucejoe said:

Good set up to have, specially to spot  overbaking, rebanking and in general faults in escape mech.  

Yes but I think I'm currently dealing with low amplitude as opposed to the rebanking basically. But I'll keep in mind.

[EatPeach]

1 hour ago, Graziano said:

Hi there not as accurate as a timing machine but it would surely give you an idea how its going , you should be getting about 250-300 degrees any more is a bonus ,yours looks like about 310 degrees .However positional error ,amplitude in different positions would be a bit more challenging . Then you've got beat error which you can't see .But I think it's ok for a general idea.  Hope this helps

Yes I agree, basically those old scrap movement is difficult to have a 270 amplitude, prositional error is even worse. Am I really have 310 in my case？ Based on Marc‘s reply is more like 180? 

[aac58]

8 minutes ago, EatPeach said:

So my case is about 180 amplitude?

Yes, Marc is right, A to B is twice the amplitude.

[Marc]

22 minutes ago, EatPeach said:

So my case is about 180 amplitude?

Yes.

What value were you getting from your timegrapher IOS app and your timing machine?

[EatPeach]

2 minutes ago, Marc said:

Yes.

What value were you getting from your timegrapher IOS app and your timing machine?

Highly unstable, from 170 to 270 even 310. So basically useless.

[Marc]

4 minutes ago, EatPeach said:

Highly unstable, from 170 to 270 even 310. So basically useless.

are you getting the same degree of instability from both the timing machine and the Timegrapher app?

[EatPeach]

2 minutes ago, Marc said:

are you getting the same degree of instability from both the timing machine and the Timegrapher app?

My timing machine is not working now, so I can't test this with this peculiar movement but generally speaking No

[Marc]

I don't know how good these mobile phone apps are, I have generally steered clear of them. I'm not convinced that the phone mic is entirely suitable, or that the app can filter out sounds that aren't the watch. Have you tried the app with a different watch to see if you get a more stable reading?

[EatPeach]

1 minute ago, Marc said:

I don't know how good these mobile phone apps are, I have generally steered clear of them. I'm not convinced that the phone mic is entirely suitable, or that the app can filter out sounds that aren't the watch. Have you tried the app with a different watch to see if you get a more stable reading?

To some extent yes, sometimes you can get a stable reading for a while and then it changed. but you can't get a stable reading without constantly  fiddling with the mic.

[Marc]

18 minutes ago, EatPeach said:

To some extent yes, sometimes you can get a stable reading for a while and then it changed. but you can't get a stable reading without constantly  fiddling with the mic.

I suspect then that the apparent instability is likely to be an artifact of the phone/app combination rather than the watch

[EatPeach]

9 minutes ago, Marc said:

I suspect then that the apparent instability is likely to be an artifact of the phone/app combination rather than the watch

yes this is highly plausible and I think the app is good but it indeed needs a quiet professional mic to make it a handy timing machine.

[JohnR725]

The key to getting a timing machine to work is a decent pick up. Using capacitive microphones like common found on phones and other devices doesn't seem to be the best way to go from past experience of other people in this group. We've had several times in the past problem solving didn't work because the signal sucked and the results on the timing whatever was invalid.  This is where buying one of the cheap Chinese self-contained timing machines is really the way to go.

Then here is an example of visually looking at your balance wheel to determine the amplitude. Or in this particular case figuring out the lift angle. Personally I find for the dot fluorescent ink with a UV flashlight Works really well.

https://youtu.be/-Xgcck692js

 

 

[EatPeach]

6 minutes ago, JohnR725 said:

The key to getting a timing machine to work is a decent pick up. Using capacitive microphones like common found on phones and other devices doesn't seem to be the best way to go from past experience of other people in this group. We've had several times in the past problem solving didn't work because the signal sucked and the results on the timing whatever was invalid.  This is where buying one of the cheap Chinese self-contained timing machines is really the way to go.

Then here is an example of visually looking at your balance wheel to determine the amplitude. Or in this particular case figuring out the lift angle. Personally I find for the dot fluorescent ink with a UV flashlight Works really well.

https://youtu.be/-Xgcck692js

 

 

Yes Agree. But I'll have to wait till the timing machine seller to repair mine then I can get a solid reading. But anyway, Marc from Watch Repair Channel also use a desktop program to tune the watch but I think he has a very professional mic input system in order to make it works.

[praezis]

A good mic surely helps. But if the software has poor signal filtering and cannot remove ambient noise (my suspicion with smartphone apps), results will stay poor.

Apps Test
Noise Filter

Frank

[jdm]

1 hour ago, EatPeach said:

But anyway, Marc from Watch Repair Channel also use a desktop program to tune the watch but I think he has a very professional mic input system in order to make it works.

Actually our Host Mark Lovick uses both a standalone machine, and a desktop application. An advantage of the latter is that it can show the sound waveform, which helps diagnosing certain problems.

[JohnR725]

5 hours ago, EatPeach said:

timing machine seller to repair mine

You found a seller that actually fixes the timing machines?

6 hours ago, EatPeach said:

Marc from Watch Repair Channel also use a desktop program to tune the watch but I think he has a very professional mic input system in order to make it works.

The software he's using can be found at the link below.  Not sure you can call a computer audio input a professional input. Although if you look at the eBay listing you can see they now have a USB sound adapter to get around the crappy computer audio inputs. Then it does come with a really nice microphone made by the company.

http://www.delphelectronics.co.uk/products.html

https://www.ebay.com/itm/Watch-Clock-Timing-Machine-S-W-Witschi-Greiner-Vibrograf-Timegrapher/112473962615

[EatPeach]

The software he's using can be found at the link below.  Not sure you can call a computer audio input a professional input. Although if you look at the eBay listing you can see they now have a USB sound adapter to get around the crappy computer audio inputs. Then it does come with a really nice microphone made by the company.
http://www.delphelectronics.co.uk/products.html
https://www.ebay.com/itm/Watch-Clock-Timing-Machine-S-W-Witschi-Greiner-Vibrograf-Timegrapher/112473962615

I brought the timing machine from them, so I think they should get it covered.

And about the software I did try it before but unfortunately normal desktop mic doesn't work. I think it needs any mic analogous to the timing machine mic or as you mentioned the mic provided by the software company. But at that particular price range I might just go for a timing machine since I'm buying on a budget.


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[JohnR725]

13 hours ago, EatPeach said:

And about the software I did try it before but unfortunately normal desktop mic doesn't work. I think it needs any mic analogous to the timing machine mic or as you mentioned the mic provided by the software company. But at that particular price range I might just go for a timing machine since I'm buying on a budget.

If you're really curious about timing machine microphones you get a clue by going through all 29+ pages at the discussion below. Somewhere in the discussion even pictures of the inside of the microphone that comes with the software.

https://www.watchrepairtalk.com/topic/3002-d-i-y-watch-timing-machine/

[Bauertime]

I prefer not to use your newfangled witchery machines. I just go by looks and sound.