This app is easy to work. It just requires a little trial and error on the sensitivity slider to find the right balance and get a reading. However, it might not work well on all watches. On my Seiko with a 6R15 movement, it can pick up the ticking from any angle and with the case back still on. However, on my Seiko with a 7S26, the ticking is too soft and the app can’t pick it up with the case back on. Another small thing is that the accuracy is not perfect, it was around +/- 3 seconds when I compared what the app reported vs a 24 hr observation against an official atomic clock. This might be because the measuring time from the app is pretty short. Good enough for practical application though. This app was a game changer for me and allowed me to regulate my watch for a tiny fraction of the cost of getting a timegrapher. I look forward to trying it on a Swiss ETA movement, etc.

This worked exactly as expected. Like reallly really well. It’s obviously not a timegrapher, but if you use as directed you can set a Seiko 7s28 to within +\- 5 seconds/day or better.I hid in a quiet closet away from my loud kids and opened the caseback, set my iPhone wired earbuds mic on the case, and got a signal no problem. The measurement is way more accurate than your ability to push the 7s28 regulating lever, so it takes a few tries. I bought this thinking it might be a bust. It was so super good this is the only online review for anything I’ve ever written. If it’s not working for you, you’re not following the directions. The accuracy I have on an SKX007 is (for now) within 2 seconds/day and it feels like a million bucks because of it. Great job!

I was able to get a reading when laying my watch face down on my iPhone near the built-in microphone (in the lower left corner). It didn’t work when laying the watch on its side—not loud enough. This did not allow me to measure my watch in different positions. I tried using my original AirPods, but that didn’t work at all. I finally pulled out the wired headphones that came with one of my iPhones. I held the microphone part against the back of the watch with a wire tie wrap. Masking tape should work even better. I set sensitivity = 2/3, noise cancellation = on, and measuring time = long. This produced stable results in most positions. These generally agreed with my seconds/day measurements for 24 hours, but of course is much faster!

I have several Japanese automatic movements that were losing time or gaming time daily. I had been trying to time them myself without any technical equipment and it was so frustrating. I downloaded this app, and was immediately able to use it to time my adjustments. 24 hours later, I have timed the movements, and they are exactly what the app said. Now, All my automatic watches are keeping reasonable time. Thank you so much for creating this app! Be sure to follow the directions for best results. It is simple.