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svorkoetter last won the day on April 24

svorkoetter had the most liked content!


About svorkoetter

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    WRT Addict

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    Ontario, Canada
  • Interests
    Electronics, Aviation, Music, Calculators, Slide Rules, Fountain Pens, and Watches

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  1. Hi All ... I just wanted to let you know that I've just released Watch-O-Scope 1.3, with the following improvements and new features: Built-in volume boost, adjustable via scope and manual adjustment modes, requiring less external amplification. Long term test improvements: Ignore extreme outliers (±4σ) for better immunity to non-timekeeping noises (e.g. the date wheel clicking over at midnight, doors slamming, cars crashing outside). Clip graphs to three standard deviations (±3σ). Highlight one standard deviation (±σ). Support for manually selected beat rates all the way down to 300 bph. Report weights for standard positions are remembered and become the defaults for subsequent reports.
  2. So far, the kit that Eland posted seems to be a good option for someone who doesn't want to start from scratch. I will pick one up when I'm in Germany later this month, and give it a try. The thing I like about it is that it doesn't use a proprietary part. The LF351 is generic, has multiple sources, and has been around for a long time. I just haven't had any experience with it before now.
  3. Yes, so long as neither the input (not likely) nor output signal is more than about 2V peak-to-peak.
  4. The gain of that circuit is only about 100 (40dB), which probably won't be adequate, and despite what the manual says, it won't run off of 3V. At 3V, the input signal is biased at 1.5V, which is of course only 1.5V below the chip's supply voltage, a point above which it will not operate. Put another way, there is zero headroom if operated at 3V. The only thing it will amplify without severe distortion is total silence.
  5. Unlike a capacitor microphone, a piezo doesn't need a power source. And a dynamic microphone is a power source.
  6. I agree with JerseyMo in principle, but of course those aren't the rules here. However, I don't see how buying a cheap knockoff piece could be "too cheap". You have a cheap knockoff watch, so why would that be any different than the original missing piece? A real Rolex piece would indeed be expensive, they won't sell you one anyway, and it probably wouldn't fit.
  7. Hi svorkoetter, Put me in the queue, very interested, ""well done".

  8. That contact mic is a piezo, and is also known to work. However, it's not very practical for working on an opened watch. The brass pin idea is sort of what we already use, except we use a pin attached to the watch movement (more commonly referred to as the winding stem and crown). It might be worth trying to cover the piezo disk with foam though, leaving a hole for the crown to go through.
  9. Those bimorph sensors are the ones I was referring to. I may try just gluing one to an alligator clip to see if that works.
  10. An actual vibration sensor, as discussed somewhere earlier in this thread, and of which I've ordered some but not yet used, would probably work even better. Guido, I wonder if your sensor would be improved by cutting down the piezo disc into just a strip?
  11. Hence the smiley in my post. If it's a lapel mic, it's not a piezo. It's an electret condenser mic. These have a built-in preamp. We tend to avoid those because they have DC current running through them, and could, in theory, magnetize your watch.
  12. Are you sure you were using a piezo mic? If a piezo mic clips on your PC's input, a regular mic would blow up the computer. Yes, WOS will work with USB audio devices. If the device is visible to Windows, WOS can use it.
  13. Yes. A piezo microphone produces a much lower signal level than a condenser mic, on the order of microvolts. Very few sound cards work with such low levels, even if they have a dedicated mic input (which most laptop sound card inputs actually are). Some amount of amplification is needed for a mic input, and even more for a line level input.
  14. Guido is right. If you are denting the piezo without the plastic there, then you are pressing the watch too tight against the piezo.
  15. The resonance is probably caused by a combination of factors. Perhaps with some watches, the yellow plastic dish vibrates against the plastic of the watch holder? I would suggest removing that dish entirely, since its shape will cause echoes, and the edges can easily vibrate.
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