Industry doesn't use microphones. It's piezo pickups or inductive pickups (coils) for things like tuning fork movements in accutrons. For quartz they use probes.
http://forums.watchuseek.com/f6/watch-timing-microphone-646148.html On Sat, Apr 19, 2014 at 11:12 AM, Chris Albertson <[email protected] > wrote: > On Fri, Apr 18, 2014 at 10:37 PM, DaveH <[email protected]> > wrote: > > > Hi Chris > > > > My concern was not the magnetization of the watch movement but the > > induction > > of eddy currents into the balance wheel which will cause drag. > > > > The act of moving the watch into the field of the pickup could cause the > > watch to start running more slowly. You will be getting a strong signal > but > > it will be the wrong signal. > > > > What is the magnitude of this effect? Would anyone know the relationship > between field strength and watch speed. For example the strength of the > Earth's magnetic field changes over at least a factor of four in different > parts of the world. Is this a seconds per day or seconds per decade kind > of problem? > > But yes I agree forsaking serious measurements I'm make a purpose built > coil. Or actually like I said two of them wires in anti-phase. > > But even then, it can't measure a mechanical watch. I think a microphone > would be best. > > > > > > > Dave > > > > > -----Original Message----- > > > From: [email protected] > > > [mailto:[email protected]] On Behalf Of Chris Albertson > > > Sent: Friday, April 18, 2014 08:44 > > > To: Discussion of precise time and frequency measurement > > > Subject: Re: [time-nuts] Measuring the accurcy of a wrist watch > > > > > > On Thu, Apr 17, 2014 at 11:12 PM, Hal Murray > > > <[email protected]>wrote: > > > > > > > > > > > > > > > Steel makes very good springs. Are there any non-magnetic > > > materials that > > > > are > > > > close? > > > > > > > > > > I think they can use some kind of non-magnetic stainless steel > > > > > > Also this might be a moot point because I got a good strong signal by > > > placing the watch on top of the guitar strings. I did not > > > have to restring > > > the guitar. The wall clock works even some inches away. > > > You don't have > > > to get really close to the magnets. If you were building a > > > sensor, just > > > use a plain iron core and 1/4 pound of #40 wire > > > > > > > > > > > > > > -- > > > > > > Chris Albertson > > > Redondo Beach, California > > > _______________________________________________ > > > time-nuts mailing list -- [email protected] > > > To unsubscribe, go to > > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > and follow the instructions there. > > > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > and follow the instructions there. > > > > > > -- > > Chris Albertson > Redondo Beach, California > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
