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Signal through the Noise – Measuring the Precision of Mechanical Watches with your iPhone

by J.Edwards

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A watchmaker’s job isn’t done once a watch is assembled and ticking. The much more abstract task of then getting that watch to keep time – in an almost infinite variety of positions, temperatures, and states of wind – takes place. It’s the most challenging part of our craft and the pursuit for perfection is ceaseless. If careful attention is paid to every detail, right from the get go, you can usually be pretty certain the timepiece will keep respectable time when you’re done with it. Getting to that perfect zero point, though, where the watch doesn’t lose or gain any time in any state, remains elusive. There are just too many variables at play. Literally hundreds.

Little idea did I have, just how naïve I was in thinking that developing a system to analyze all of that ordered chaos would be a simple and straightforward process. Throw in several more dimensions of variability, like differing calibres and escapements, case sizes and materials, ambient noise, processor speeds, and the varying frequency response of microphones, and the end goal becomes that much more complex and less than straightforward to achieve. Following several more months of development on Kello, though, and thanks to the input of a small army of beta-testers, I’m confident I’ve finally got it pinned down in a format tight enough to run on Apple’s latest mobile devices.

With the initial release of Kello, my focus was aimed at making chronometric sense of the data pouring in through the microphone. That first version had to be used in near perfect silence and there was no means of controlling the level of amplification that the incoming audio was being analyzed at. I had unwittingly tailored the app to a relatively small cross section of watches and accustomed myself to working with and compensating for its inadequacies. The result was less than acceptable.

After making the decision to pull the first version of Kello from the App Store, I committed myself to focus on eliminating inadequacies in its performance due to external variables. It took a lot of work to bring Kello to the point it is at today and I am very pleased with the results running on Apple’s ARMv7 based mobile devices.

Completely rewritten, from the ground up, the latest version Kello (which is now available on the iTunes App Store), brings a number of new features and updates that make it easier for the end user to achieve reliable results. The frequency of the watch can now be set manually or detected automatically by Kello, and the range of usable frequencies has been expanded to include 14,400. The amplification of the incoming audio signal can now be adjusted using a simple, on screen slider. The audio data being analyzed by Kello is displayed in wave form, so the user can see exactly what Kello is seeing and adjust the amplification or microphone position accordingly. Lastly, and most importantly, Kello 2 introduces the use of DSP to focus in on the sound of the watch ticking and help eliminate ambient noise.

To see Kello in action, analyzing a Rolex Sea Dweller in a noisy room, check out this video on YouTube.

All of this improved performance comes at a cost, though. DSP is CPU intensive. Unless you have the patience of a saint, Kello 2 is only recommended for use on the iPhone 3GS or higher. The iPhone 3G and second generation iPod Touch struggle to run the app and will crash if they’re running low on memory or haven’t had a fresh reboot recently. I do not recommend trying to run Kello on these devices. I am working to bring this awesome piece of tech to Apple’s older hardware, but it’s proving to be one heck of a mountain to summit.

In the mean time, I hope that those of you with 3rd and 4th gen iPhones and iPod Touches will benefit from having a timing machine in your pocket as much as I have.

Update: Kello has now been updated to better support the 2g iPod Touch and iPhone 3G.

Win a Free Copy of Kello

The first five readers to correctly answer one, each, of the following questions will receive a free copy of Kello from the US App Store. One answer per email address.

Here goes:

  1. What English observatory did Bonniksen’s karrusel watches consistently earn top marks at, around the turn of the 20th century?
  2. At which observatory did Kari Voutilainen have the first in his series of Obervatoire watches tested at?
  3. Which former Royal Observatory did George Daniels first have his hand made pocket watches tested at?
  4. Who is the maker of the chronometre that currently adorns the wrist of George Daniels and is engraved “to George Daniels my Mentor 2010”?
  5. Which watch brand took top marks at the 2009 Chronometrie International Timing Competition?

Good luck!

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  1. Posted October 23, 2010 at 1:43 am | Permalink

    I’m guessing the variables for writing this app for a windows platform would be a nightmare. Any plans on a Windows 7 version or do I have to trade in my Krazor for an Apple? (I know, I’m a few years behind the trend)

  2. Ibby
    Posted October 23, 2010 at 3:07 am | Permalink

    4. Rodger Smith…

  3. sdchew
    Posted October 23, 2010 at 3:34 am | Permalink

    Great work all these months!

  4. Posted October 23, 2010 at 8:04 am | Permalink

    @Robert No plans for branching out to other platforms yet. I’m keeping my focus on improving performance and filling out Kello’s features on iOS right now.

    @Ibby Good guess, but not quite there. You’ll have to swim across the English channel to land on this watchmaker’s home shores.

    @Sdchew Couldn’t have done it as quickly or as thoroughly without you. Thanks!

  5. ei8htohms
    Posted October 23, 2010 at 10:09 am | Permalink

    Please, please, please make an Android version of this software. You will be my hero.

  6. Posted October 23, 2010 at 11:05 am | Permalink

    Very intriguing! What are your thoughts on running it on the iPad?

  7. Posted October 23, 2010 at 12:34 pm | Permalink

    The A4 processor in the iPad can handle it. An external mic is required, though. I am working to tailor the interface to the iPad. Once iOS 4.2 launches, in November, the current version of Kello should run no problem.

  8. Ibby
    Posted October 23, 2010 at 1:39 pm | Permalink


  9. Ibby
    Posted October 23, 2010 at 6:31 pm | Permalink

    5. Jaeger lecoultre 🙂

    Second go then il give up….


  10. Posted October 23, 2010 at 7:12 pm | Permalink

    1) Kew
    2) Besancon Observatory
    5) JLC

    Have to look up the observatory Daniels used. Excited to take this timer for a spin one way or another. Glad it is smoother now.


  11. Posted October 23, 2010 at 9:15 pm | Permalink

    Right answers Ibby and Jacob! Check your inboxes to redeem your free copies of Kello.

    Still three more up for the taking.

  12. G. Verstick
    Posted October 24, 2010 at 10:09 pm | Permalink

    Hi: what an ingenious idea for an app!
    Good luck with it.
    (Hope I win…)
    1. Kew
    2. Besancon Observatory
    3. Royal Greenwich Observatory
    4. FPJ
    5. JLC

  13. Posted October 25, 2010 at 9:07 pm | Permalink

    Technically, based on word order, #3 is correct, but not the full answer I was looking for. It should be pretty easy to deduce now.

    Five for five. Great job! Enjoy your copy of Kello, G.

  14. Beans Baxter
    Posted November 2, 2010 at 2:12 pm | Permalink

    3. In 1980 when the testing was done, it was called the Old Royal Observatory. As of 1998, it is again Royal Observatory, Greenwich.

  15. Vikings1215
    Posted November 10, 2010 at 9:10 pm | Permalink

    1. Kew Observatory, London
    2. Besançon Observatory, Besançon, France.
    3. Royal Observatory, Greenwich, London
    4. F.P.Journe
    5. Jaeger-LeCoultre

    But I guess they have already been answered

  16. Posted November 21, 2010 at 6:08 pm | Permalink

    @Beans Baxter & Vikings1215 answers to number 3 are close, but still off the mark.

    Daniels mentions the actual location in the following series of video interviews:

  17. Ben
    Posted November 25, 2010 at 10:37 am | Permalink

    I downloaded Kello and have really enjoyed playing around with it. While it won’t give as much information as my Tickoprint paper tape machine, I really like having a digital display. Plus, my iPhone fits on my main bench a lot more easily than my Tickoprint.

    There’s one thing that’s missing, though, that I would really like to see added. I work on a lot of early American watches that run at 16,200 bph. I’d like to see support for this frequency added.

  18. Posted November 26, 2010 at 1:01 pm | Permalink

    Thanks for the request, Ben. I will work to integrate 16,200 into the next update.

2 Trackbacks/Pingbacks

  1. […] from ground up, implementing noise filtering and making the interface more intuitive. Read more on Tick Talk Watchmaking Blog, where you can win a free licence of Kello for your Apple portable […]

  2. […] Jon Edward’s Kello is an app for measuring the accuracy of a mechanical watch and show you many seconds per day your watch is gaining or loosing.  I first became aware of Kello back in July – apparently the app was first released earlier this Summer, but developer Jon Edwards quickly removed the app from the iTunes App Store and went back to the drawing board after an avalanche of negative feedback from early adopters.  Recently however Edward’s re-released Kello, and it is again available for $8.99.  You can read more about Kello’s development history here. […]

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