Wayne as I work through the chronverter I do know the good phase tracking clocks really demand on frequency behavior. As I measured its +/- .6 Hz at 60 KHz. I believe the cheapy wall clocks are a bit wider, but not sure as they are hard to actually measure. They do use a small tuning fork crystal and from experience these are sharp. When I experimented with them they were maybe 5 Hz. Indeed the Chinese website had 25 X 60 KHz crystals for maybe $2. With respect to the antenna. My thinking is a loopstick resonated on 60 KHz and most likely driving it push pull or single ended. Thats 1 transistor if single ended as common collector if I had to guess. The reason is the micros put out a fair level of signal so its a case of upping current into the antenna. But it really will be a bit of experimenting. I did look at your code and that was so nice it opened up straight into the arduino IDE. Regards Paul WB8TSL
On Thu, Aug 30, 2018 at 5:12 AM, Wayne Holder <[email protected]> wrote: > For anyone trying out my ATTiny85 code, I've done some additional tests and > find that placement of the antenna near the clock is very finicky and, so > far, the only way to get a reliable decode of the time in the clock is by > using a scope to monitor the demodulated output and then moving the antenna > around until the demodulated signal lines up cleanly with modulated carrier > and there are no intra bit glitches. This can take a bit of patience, so > clearly a better solution needs to be found. I've found that any type of > glitch in the demodulated signal seems to prevent the clock chip from > decoding the time. > > It's possible the difficultly with locking onto my simulated WWVB signal > may be partially due to the design of the clock (from my location it's > never been able to to lock onto the real WWVB signal), but I have no > reference to compare it against so, for now, I have conclude that the > PWM-based modulation scheme my code uses may also be suboptimal for this > application. To make testing even more frustrating, the BALDR clock I'm > using will only look for a signal for about 6 minutes before it goes to > sleep and I have to then power cycle the clock to get it to listen again. > > So, keep this in mind if you're going to try and replicate my results. > > Wayne > > On Wed, Aug 29, 2018 at 6:03 PM Wayne Holder <[email protected]> > wrote: > > > For those that have asked for my to publish the source code for my > > ATTiny85-based WWVB simulator, I have put up a somewhat hurriedly written > > page on my google site at: > > > > https://sites.google.com/site/wayneholder/controlling-time > > > > that describes a bit about how the code works, how to compile it using > the > > Arduino IDE, how I tested it, some issues I have observed in testing it > > and, at the bottom of the page, a downloadable zip file that contains the > > complete source code. > > > > Note: as mentioned at the top of this page, this is currently a work in > > process, so I'm not yet going to link the article to my main website > page, > > so you'll need to link in this post to find it. Also, as draft, I'm > going > > to continue to revise the page until I feel the project is complete > enough > > to publish. That means the source code zip file is going to potentially > > change from time to time, too. > > > > Wayne > > > > On Wed, Aug 29, 2018 at 1:35 AM Wayne Holder <[email protected]> > > wrote: > > > >> As a follow up, I now have a simple WWVB simulator written in C that's > >> now running an an ATTiny85 using nothing more than the internal, 8 > >> mHz oscillator and about a 6 inch length of wire connected to one of the > >> pins as an antenna. It generates an approximate 60 kHz signal using > PWM on > >> timer 1. I tweaked the timer value a bit to correct for some variance > in > >> the internal oscillator, but I' not even sure that was necessary, as my > >> target is just a BALDR Model B0114ST, consumer grade "Atomic" clock. > >> Modulation is done by varying the duty cycle of the PWM to approximate > the > >> -17 dBr drop on the carrier. But, again, I don't think this value is > >> critical with a consumer clock chip. I tapped the demodulated output > >> inside the clock and displayed it on my scope along with the generated > >> signal and I got good, steady demodulation with the wire antenna just > >> placed near clock. The next step is to connect up a GPS module and add > >> code to use it to set the time. I'm also going to change the code to > use > >> the PPS signal from the GPS to drive the output timing rather than the > test > >> code I have now that uses timer 0 to generate the PPS interrupt. I'm > happy > >> to share details if anyone is interested. > >> > >> Wayne > >> > >> > >> > >> On Sun, Aug 26, 2018 at 2:51 PM, paul swed <[email protected]> wrote: > >> > >>> That would be a great neighbor to have but I can tell you around here > its > >>> the phone. Not to concerned about someone putting up a wwvb > replacement. > >>> And I can always up the power. Chickle. > >>> Regards > >>> Paul > >>> > >>> On Sun, Aug 26, 2018 at 2:34 PM, Bob kb8tq <[email protected]> wrote: > >>> > >>> > Hi > >>> > > >>> > The gotcha is if you have neighbors two or three doors away that > *also* > >>> > put up one of > >>> > these devices. You then have a real problem with the neighbor(s) in > the > >>> > middle. The > >>> > wavelength is long enough that Raleigh issues won’t get you. You > still > >>> > have the two > >>> > signals ( at slightly different frequencies) beating against each > >>> other. > >>> > The result is > >>> > going to show up as who knows what to this or that receiver. With a > >>> > precision receiver, > >>> > you might even have issues from the guy two houses away …... > >>> > > >>> > Bob > >>> > > >>> > > On Aug 26, 2018, at 1:08 PM, paul swed <[email protected]> > wrote: > >>> > > > >>> > > Agree with the conversation. With respect to neighbors when the day > >>> comes > >>> > > they may ask you to boost your signal. :-) > >>> > > Granted maybe the day won't come but at least having your local > >>> clocks > >>> > work > >>> > > is nice. > >>> > > Regards > >>> > > Paul > >>> > > WB8TSL > >>> > > > >>> > > On Sat, Aug 25, 2018 at 10:29 PM, Dana Whitlow < > >>> [email protected]> > >>> > > wrote: > >>> > > > >>> > >> With the watch being physically close to the faux WWVB > >>> "transmitter", > >>> > one > >>> > >> is in > >>> > >> the so-called "near field" regime, where the field strength (V/m) > >>> falls > >>> > as > >>> > >> the inverse > >>> > >> cube of the distance. If one is putting the watch, say, within a > >>> few > >>> > >> inches of the > >>> > >> transmitter, reliable reception should be available yet the signal > >>> > should > >>> > >> be literally > >>> > >> undetectable by any practical receiving device more than a few > feet > >>> > away. > >>> > >> Hence, > >>> > >> meeting the FCC field strength limit should be trivial.if the > >>> device is > >>> > >> used as pictured. > >>> > >> However, if one cranks up the power enough to reliably cover one's > >>> > entire > >>> > >> house, > >>> > >> then there might be a problem depending how close the nearest > >>> neighbor > >>> > >> lives, > >>> > >> even at levels well within the FCC limit he quotes. > >>> > >> > >>> > >> Taking the near field relationship in hand, 40 uV/m at 300m would > >>> > translate > >>> > >> into > >>> > >> a whopping 0.135 V/m at 20 meters range, more than enough to feed > >>> most > >>> > >> peoples' > >>> > >> entire house. So the pragmatic issue would again be- neighbors. > >>> On the > >>> > >> other > >>> > >> hand, most of them would never be aware of the local signal as > long > >>> as > >>> > they > >>> > >> get good > >>> > >> time settings, unless they live close enough to Ft. Collins for > the > >>> two > >>> > >> signals to > >>> > >> contend with each other. > >>> > >> > >>> > >> It looks to me like the ferrite rod antenna is considerable > >>> overkill. > >>> > Even > >>> > >> with no > >>> > >> purposeful antenna I'd expect leakage to yield sufficient signal > >>> for at > >>> > >> least a few > >>> > >> inches. > >>> > >> > >>> > >> Dana > >>> > >> > >>> > >> > >>> > >> On Sat, Aug 25, 2018 at 8:11 PM Wayne Holder < > >>> [email protected]> > >>> > >> wrote: > >>> > >> > >>> > >>> This guy has what looks like a well thought out design using a > >>> > Sirf-Based > >>> > >>> GPS and ATTiny44A chip to generate a signal to update his watch: > >>> > >>> > >>> > >>> https://www.anishathalye.com/2016/12/26/micro-wwvb/ > >>> > >>> > >>> > >>> Unfortunately, he doesn't seem to have published a schematic or > his > >>> > >> source > >>> > >>> code. But, he covers enough detail that I think it wouldn't be > too > >>> > hard > >>> > >> to > >>> > >>> replicate what he's done. Or, perhaps he would disclose these > >>> details > >>> > if > >>> > >>> contacted. > >>> > >>> > >>> > >>> Wayne > >>> > >>> > >>> > >>> On Sat, Aug 25, 2018 at 4:33 AM, D. Resor < > [email protected]> > >>> > >> wrote: > >>> > >>> > >>> > >>>> I thought I would search in a different way for a WWVB signal > >>> > generator > >>> > >>>> design. I found this item. While the designer explains it > isn't > >>> as > >>> > >>>> accurate as WWVB it may be another starting point. > >>> > >>>> > >>> > >>>> http://www.tauntek.com/wwvbgen-low-cost-wwvb-time- > >>> > signal-generator.htm > >>> > >>>> > >>> > >>>> > >>> > >>>> > >>> > >>>> Donald R. Resor Jr. T. W. & T. C. Svc. Co. > >>> > >>>> http://hammondorganservice.com > >>> > >>>> Hammond USA warranty service > >>> > >>>> "Most people don't have a sense of humor. They think they do, > but > >>> they > >>> > >>>> don't." --Jonathan Winters > >>> > >>>> > >>> > >>>> _______________________________________________ > >>> > >>>> time-nuts mailing list -- [email protected] > >>> > >>>> To unsubscribe, go to http://lists.febo.com/mailman/ > >>> > >>>> listinfo/time-nuts_lists.febo.com > >>> > >>>> and follow the instructions there. > >>> > >>>> > >>> > >>> _______________________________________________ > >>> > >>> time-nuts mailing list -- [email protected] > >>> > >>> To unsubscribe, go to > >>> > >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>> > >>> and follow the instructions there. > >>> > >>> > >>> > >> _______________________________________________ > >>> > >> time-nuts mailing list -- [email protected] > >>> > >> To unsubscribe, go to http://lists.febo.com/mailman/ > >>> > >> listinfo/time-nuts_lists.febo.com > >>> > >> and follow the instructions there. > >>> > >> > >>> > > _______________________________________________ > >>> > > time-nuts mailing list -- [email protected] > >>> > > To unsubscribe, go to http://lists.febo.com/mailman/ > >>> > listinfo/time-nuts_lists.febo.com > >>> > > and follow the instructions there. > >>> > > >>> > > >>> > _______________________________________________ > >>> > time-nuts mailing list -- [email protected] > >>> > To unsubscribe, go to http://lists.febo.com/mailman/ > >>> > listinfo/time-nuts_lists.febo.com > >>> > and follow the instructions there. > >>> > > >>> _______________________________________________ > >>> time-nuts mailing list -- [email protected] > >>> To unsubscribe, go to > >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >>> and follow the instructions there. > >>> > >> > >> > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to http://lists.febo.com/mailman/ > listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
