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Measure the Precision of Mechanical Watches using your iPhone (Updated 2x)

by J.Edwards

Kello Mechanical Watch Analyzer

After nearly a year and a half of development, I am very, very pleased to announce the worldwide debut of Kelloa timing machine for the iPhone – on the iTunes App Store this week!

The evolution of processor capabilities used in smartphones has improved dramatically in recent years and many of us now carry far more processing power in our pockets than is necessary to run timing machines like Witschi’s Watch Expert or the classic Vibrografs. Such timing machines are expensive, though, and far from portable.

I am blessed to have a Watch Expert II to use at work, but can’t afford to spend the necessary coin on a decent timing machine to use at home on “hobby projects” and watches for friends or family. When speaking with acquaintances or potential clients about their watches while not at work, I’ve often wished I had timing machine in my pocket to help me diagnose problems and offer better advice on the spot. When working on the precision timing of chronometer grade wristwatches, like Rolexes, I’ve also often wished that Witschi’s Watch Expert displayed timing data to within 1/10 of a second. All of these frustrations, coupled with the powerful tools available through Apple’s Developer Program, are what led me to develop Kello.

The app works by using the microphone of the iPhone, iPad, or iPod Touch to analyze the regularity of the ‘tick-tock’ sound generated by the escapement of a mechanical watch. I designed Kello to automatically detect the frequency of the watch being analyzed as well as the beat error of its escapement. Using the data collected, Kello compares the rate of the watch against the much more precise internal time signal of the iPhone and then outputs how much time, in seconds, the watch is gaining or losing each day. If the watch is running within +/-10 seconds/day, Kello will display this gain or loss to a precision of 1/10 of a second.

I have been testing the app for a little over a month now on a second generation iPod Touch as well as on a kind friend’s iPhone, and have been happy with the results. The only caveat I’ve found in testing it in the wild, is that analysis has to be performed in near perfect silence to yield optimal results. I am working hard to bring honed frequency analysis to the next version of Kello to greatly eliminate timing anomalies due to external noise.

In the mean time, I am really looking forward to seeing how it performs for other watchmakers, as well as watch collectors, particularly on Apple’s faster A4 processor, and I intend to evolve it into a much more sophisticated, pocket-sized timing machine, able to perform on par with a Witschi, as the native iOS APIs and iPhone hardware continue to improve.

Update 1: In light of the tidal wave of feedback I’ve received since Kello went live on the App Store, I realize that I babied the app too much in testing and that it’s not quite ready for full public consumption. Due to the large number of people who have had trouble getting Kello to work successfully, I’ve decided to pull the app from the store and head back to the drawing board to focus on making it easier for the end user to derive reliable results without having to toy with microphone positioning or eliminating ambient noise.

Update 2: Kello is back on the iTunes App Store, updated with new signal processing algorithms to focus in on the sound of the watch’s escapement and help eliminate ambient noise.

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  1. Posted July 11, 2010 at 9:31 pm | Permalink

    Damn! I just bought a microset, sigh. Bought a copy of this anyway. 😉 Can’t wait to see how it works. Think it’d work with an external contact microphone?

  2. sdchew
    Posted July 11, 2010 at 9:32 pm | Permalink

    Will this work with watches which do not use the Swiss Lever Escapement? (e.g. Co-axial movement)

  3. J.Edwards
    Posted July 11, 2010 at 9:52 pm | Permalink

    I only had access to one co-axial watch while testing Kello and the results were comparable to the Watch Expert. Kello is programmed to recognize the odd frequency (25,200bph) of some iterations of the co-axial, as well.

  4. Rudi
    Posted July 11, 2010 at 9:56 pm | Permalink

    Too bad it requires iOS4 or above! Can’t use it with iPad…

  5. sdchew
    Posted July 11, 2010 at 10:17 pm | Permalink

    Cool! I’ll give it a spin.

  6. Jakub
    Posted July 11, 2010 at 11:04 pm | Permalink

    Very low signal with my 3gs so the results are unusable. I will try with other watches later but i guess the microphone will be problem…

  7. sdchew
    Posted July 11, 2010 at 11:28 pm | Permalink

    Kello seems to be able to lock on to my BA GMT’s beat rate (28,8k). Precision seems to run all over the shop thou. I’ll try again when I get to a really quiet place.

  8. Jason Taylor
    Posted July 12, 2010 at 1:01 am | Permalink

    Cool, access to a timing machine in your pocket. Being the tinker that I am I would use this app to develope my knowledge of mechanical watches and keep my Omega PO & SMP in trim.
    Nice job.

  9. knirirr
    Posted July 12, 2010 at 2:58 am | Permalink

    This looks very interesting.

    Have you tried it with any electronic balance wheel movements? I have a few of these watches and would like something with which to adjust them.

    Also, does it require the external microphone or will the iPhone’s internal ones suffice?

  10. randb
    Posted July 12, 2010 at 4:36 am | Permalink

    Cant get it to work what mic are you using? I have an apple one.

  11. randb
    Posted July 12, 2010 at 4:45 am | Permalink

    I cant get it to work it says my speedmaster is 18000 then 28800 then 36000 with constant 9.9ms beat error regardless of the watch. i forget the beat rate of the speedy but i dont think it is any of these. I used the apple mic that comes with the iphone. The signal is only slight and never gets into the green. I even took the back of a seiko diver to see what would happen and the results are all over the shop and make no sense. I dont think the mic is sensitive enough. Maybe I am doing something wrong. I placed the mic on the back with blutac to keep it still and placed the watch down no movement and no ambient sound still made no difference. Its a pity because it looks like a pretty cool piece of kit. I thin you should be able to manually pick the beats per hour rate. Cheers

  12. J.Edwards
    Posted July 12, 2010 at 5:38 am | Permalink

    When Kello has a good fix on the watch’s rate the signal quality light will glow green, if it’s red or flickers red/green it’s not getting a clear fix.

    Another leg up that the Witschi’s have, apart from the narrower frequency analysis, is the holder that the watch rests in while being timed, which keeps both the watch and mic stable. An ad hoc method I used was to attach the microphone to the watch using watchmaker’s rodico (basically sticky tack) and then held the watch steady in my fingers or on something soft like a pillow. I found that resting the watch on hard surfaces created a slight reverb. Having a small cushion of air between the mic and the watch case also helped, by eliminating any sort of resonance from the case.

    To time a bare movement, you obviously can’t stick a microphone to it. In these cases, I set the movement in Bergeon’s classic, ‘Slick’ movement holder and attached the mic to the holder’s cross bars with Rodico.

    I am interested to see what solutions other watchmakers come up with. I plan to make an actual holder, like those that ship with the Witschi and Vibrograf timing machines. Particularly if Bluetooth mics yield consistently good results. Having a wireless stand to hold watches in while timing would be really fantastic!

  13. Posted July 12, 2010 at 5:43 am | Permalink

    This is really great! I’ve got several watches with the same 7750 movement, and I’ve always wanted to compare their performance between watchmakers! Seems like an ideal tool.

  14. Owain Davies
    Posted July 12, 2010 at 8:22 am | Permalink

    I’ve just downloaded this app, and tested it with two watches.
    It was in a silent room, with the microphone as close to the watch as possible.
    There was almost no sound being recognised, and it was unable to produce a reading.
    I’m a bit dissapointed with that sounds like it could be a great app

  15. sdchew
    Posted July 12, 2010 at 8:31 am | Permalink

    Had a little more success at home. I found that the Shure iPhone adaptor seems to have a better mic that the original iPhone headset. Also, after positioning the mic next to the movement, cover the entire watch and the mic with a thick towel to damp the surround noise.

    Moving ahead, I think there needs to be some kind of signal processing to help remove the background noise. Else, this will never work on the go.

  16. Cameron Peck
    Posted July 12, 2010 at 9:57 am | Permalink

    This has great potential. I wonder if there is a cheep mic we can get at Radio Shack to make this more reliable?

  17. Matt
    Posted July 12, 2010 at 11:30 am | Permalink

    I’m wondering if it’s possible to take advantage of the iPhone 4’s noise cancelling Mic to get a better reading. My ETA6497 got picked up right away as 18,000 (good), but the reading was all over the place from 400 sec per day to -160 sec per day.

  18. winterwold
    Posted July 12, 2010 at 11:49 am | Permalink

    This app seems great! I hope to try it out.
    I would make use of it whenever I go hunting at the auctions looking for (mostly) old pocketwatches. Most of the time no one can answer any questions about the watches they are selling other then that it belonged to their grandfather. Getting information about the the frequency of the movement could be really helpful sometimes.

  19. Mike
    Posted July 12, 2010 at 12:27 pm | Permalink

    This is a great app for watchmakers business from the point of all the folks out there that self-regulate.

    Guess I should order up some more balance completes 🙂

    Certainly has potential, but sadly $9.00 or $999.00 is not going to cut it for checking any rate of a watch.

  20. WatchMark
    Posted July 12, 2010 at 6:33 pm | Permalink

    This app, once you get it working correctly that is, should be an excellent tool for those of us that cannot afford the real thing. You might want to change the name of it to something more descriptive. The name of this site is actually very good, and descriptive (generically telling people what is about, just by reading the name). But unless Kello means something, the app could use a less jabrone name.

  21. Charles Johnson
    Posted July 13, 2010 at 3:05 am | Permalink

    Hi mate I own a small but very busy watch repairs and sales shop here in the uk and would love to try the watch timer for iPhone out.
    I have the new iPhone 4 so let’s see if apples new super chip and the ability to have multiple applications open at once makes things any better.
    Keep up the good work my friend.
    Charles Johnson.

  22. J.Edwards
    Posted July 13, 2010 at 5:28 am | Permalink

    ‘Kello’ means ‘clock’ in Finnish. I named the app Kello in honour of Kari Voutilainen, whose work as a modern day watchmaker I deeply admire, as well as in hommage to the master clocks used by watchmakers to time their watches before the advent of timing machines.

  23. Jason
    Posted July 14, 2010 at 10:51 am | Permalink

    Sorry to hear about the issues people are having; as a developer myself, I know it can be hard to make things bulletproof, and what works 100% for you at home can fall apart for somebody else.

    If you need help beta testing, I’ve got an iPhone 3G and iPad that I could test on.

  24. Cameron Peck
    Posted July 14, 2010 at 11:38 am | Permalink

    I would be willing to test it on my iPad as well as iPhone 3G.

  25. Posted July 16, 2010 at 7:26 am | Permalink

    Thank you to everyone who stepped up to volunteer as a beta tester, both through email and comments here on the blog. I haven’t been able to get back to everyone individually yet, but rest assured that everyone who has touched base with me as of today will be receiving a beta copy. I am doing my best to get back to the emails as quickly as I can, if you haven’t heard from me yet I will definitely be in touch with you within the coming week and I hope to have the beta in your hands soon thereafter.

  26. randb
    Posted July 23, 2010 at 10:28 pm | Permalink

    I think it will be great once the bugs are ironed out I am more than willing to assit with beta testing. This app has huge potential.Cheers

  27. Posted July 25, 2010 at 5:39 pm | Permalink

    I would be happy to have you assist with testing the updates, Randb

  28. Jim
    Posted August 2, 2010 at 8:15 pm | Permalink

    The concept is very cool. Does/will the app show amplitude? With amplitude, I can answer that “Does it need service or regulation?” question without opening the watch.
    Do you plan on notifying people when your app is available again?

  29. Bill
    Posted August 13, 2010 at 6:13 pm | Permalink

    Any chance of getting this on Android once the kinks have been ironed out?

  30. Dave
    Posted August 28, 2010 at 11:24 pm | Permalink

    Hi, I stumble upon your app, just when you pulled it off the market. Just wondering how its coming along and if it’ll be released again? Looking for such an app.
    Good luck, Dave.

  31. Posted October 14, 2010 at 8:37 pm | Permalink

    An updated version of Kello has been released on the App Store

    @Jim Amplitude measurement is in the works. I have all the math worked out, it’s just a matter of applying it to the signal analysis reliably. At the moment, I’m still concentrating on isolating the audio signal as effectively as a Witschi – no small feat.

    @Bill Maybe.

  32. E
    Posted January 7, 2011 at 4:24 pm | Permalink

    Hope your efforts are ongoing, and not discouraged by feedback; as an under- $10 alternative to $250-3500 devices, the gripers certainly have a lot of nerve to imply they were ripped off. A beta to be sure, but what a boon when finished!
    Possible refinements / approaches:
    A 2-step initiation phase, where it initially detects the frequency, but the user then manually selects/”locks” that and avoids further confusion?
    Refinement of sonic filtering, both to reduce other incidental noise, and help narrow the focus of meaningful frequencies?
    Of course, how you accomplish these things is more involved than the mere suggestions (which other posters may not be willing to admit). Good luck – I had been musing about whether anyone was trying to create such a “watch regulating” app.

  33. Posted January 20, 2011 at 10:34 pm | Permalink

    Thank you for the kind remarks, E.

    Development is definitely still ongoing. Both of the suggestions you made have actually been implemented already via an update which was released in October. The only difference being that the 2-step detection/locking of the frequency is optional for the user and not required.

  34. felix
    Posted January 12, 2012 at 11:37 am | Permalink

    dear mr. E, will you be expanding the app to pick up clocks? Granfather clocks in perticular, if so, I would be more than willing to purchase the kello app.

  35. Posted January 13, 2012 at 10:47 pm | Permalink

    Hi Felix,

    Thanks for your interest. I am working on a version that includes clock frequencies.

    In the meantime, you may be interested in looking into an app known as Clockmaster.

  36. Mark
    Posted November 6, 2012 at 7:07 pm | Permalink

    I have been using this app for awhile now and really like it. Unfortunately, I recently upgraded to the iphone 5 and the app doesn’t seem to work anymore. Any thoughts or advice?

  37. Posted November 6, 2012 at 11:38 pm | Permalink

    @Mark Kello has taken a performance hit with iOS 6. I am working on an update to address the issue.

  38. Stu
    Posted November 15, 2012 at 4:20 am | Permalink

    Mr Edwards, kello is a great app! After upgrading to ios6 I noticed stability issues, glad I found this is a known issue now. I was wondering how the update is coming along?


  39. Posted November 15, 2012 at 9:58 am | Permalink

    Hi Stu,

    The update has been submitted to the App Store and is currently awaiting approval from Apple.

  40. Stu
    Posted November 15, 2012 at 10:35 pm | Permalink

    Much better stability!

    On average the reading wanders six seconds over a period of three minutes, beforehand it would wander anything up to about twenty seconds!

    Many thanks!

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