I’ve designed and built an Arduino based clock that receives the time from an NTP server, converts the time to voltages, and outputs the voltages to analog volt or ammeters using the PWM pins on the Arduino. The clock displays hours, minutes and seconds, each on a separate analog meters with customized clock faces. The design, code, and clock faces, and a picture of the clock are in the public domain, and I’ve posted all the information required to build this clock in a GitHub folder (www.github.com/majanoff). The clock faces are in PDF format (for Weston 301 panel meters) that can be printed and glued onto the meter metal faces. If you are interested in building the clock, I can create custom faces based on your meters or there is a link in the folder pointing to the meter face software. I’ve also built the same clock using time from a GPS receiver and a DS1307 real time clock module (posted on GitHub) in-place of the NTP internet connection. I used lookup tables for the output voltages for each of the meters, as there is a bit of non-linearity in the output, which can be corrected via the lookup tables.
Please contact me directly if you are interested in more information. Mitch. Kc2mfb -------------------------------------------- On Sun, 2/24/19, <[email protected]> wrote: Subject: time-nuts Digest, Vol 175, Issue 33 To: [email protected] Date: Sunday, February 24, 2019, 12:00 PM Send time-nuts mailing list submissions to [email protected] To subscribe or unsubscribe via the World Wide Web, visit http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com or, via email, send a message with subject or body 'help' to [email protected] You can reach the person managing the list at [email protected] When replying, please edit your Subject line so it is more specific than "Re: Contents of time-nuts digest..." Today's Topics: 1. Re: Bricked Garmin GPS 18x LVC (Hal Murray) 2. Re: Clock project request from IEEE (John Reid) 3. Re: HP Stories: An architectural view of the HP 5060/5061 and awkward oscillator adjustments. (Rice, Hugh (IPH Writing Systems)) ---------------------------------------------------------------------- Message: 1 Date: Sat, 23 Feb 2019 14:23:34 -0800 From: Hal Murray <[email protected]> To: Discussion of precise time and frequency measurement <[email protected]> Cc: [email protected] Subject: Re: [time-nuts] Bricked Garmin GPS 18x LVC Message-ID: <[email protected]> Content-Type: text/plain; charset=us-ascii > If you open it up, then simply connect a load resistor, perhaps in the > neighborhood of 100 ohms (but definitely not a direct short!) across the > super cap to drain it faster. I couldn't open mine up. I got one into a useless state. I don't know how I did it, but it wasn't updating firmware. Mine recovered after a while, but I don't know how long it took. I tossed it on the junk pile because it was useless. Eventually, I tried again and it worked. Note that trying too soon probably charges up the super cap and thus restarts the clock. -- These are my opinions. I hate spam. ------------------------------ Message: 2 Date: Sun, 24 Feb 2019 11:51:13 +0000 From: John Reid <[email protected]> To: "[email protected]" <[email protected]> Subject: Re: [time-nuts] Clock project request from IEEE Message-ID: <cy4pr13mb1208932c9cad0f2492d7684ff8...@cy4pr13mb1208.namprd13.prod.outlook.com> Content-Type: text/plain; charset="utf-8" I would love something that gave a list of options set from the location in the NMEA string. Such as this time zone or different, with nearby zones first; DST on/off. Could get to be a significant effort very quickly, but maybe there are xml files out there that would make it easy? John On 24/2/19 4:00 am, [email protected]<mailto:[email protected]> wrote: Message: 4 Date: Sat, 23 Feb 2019 15:47:11 +0100 From: Magnus Danielson <[email protected]><mailto:[email protected]> To: [email protected]<mailto:[email protected]>, Glenn Zorpette <[email protected]><mailto:[email protected]> Subject: Re: [time-nuts] Clock project request from IEEE Message-ID: <[email protected]><mailto:[email protected]> Content-Type: text/plain; charset=utf-8; format=flowed Hi, On 2019-02-22 19:31, Tom Van Baak wrote: I received the following email and permission to post it on time-nuts: Hello, I am the executive editor of the IEEE's flagship magazine, IEEE Spectrum. I recently acquired a TAPR "Pulse Puppy" and I am intrigued by the idea of using it to build a very precise clock that I would share with Spectrum's readers. I would like to partner with an engineer with experience in digital clocks, who would be credited as co-author on this project. Can you suggest someone who might be interested in this project? I would be much obliged if you had some suggestions. Kind regards, -Glenn Glenn's contact info is: Glenn Zorpette [email protected]<mailto:[email protected]> You can just imagine all the many ways the project could head. Send Glenn a note if you want to help. Or post here if you have suggestions. I think we should contribute with our wealth of knowledge. There is several aspects that would form a digital clock. Many of the pieces is readily available, but we rarely put them together in a system. The TAPR Pulse Puppy is a nice little thing. I don't have one myself, but I can see how it could be useful, so thanks for making it aware of it. The Pulse Puppy obviously solves two things, one having a crystal oscillator and output a divided down signal. To build a clock system we should consider from where we get the time, and how we maintain it. These days the answer will be a GPS module which output it's time in serial form, such as the NMEA output format. That will give us the date and time of day that the PPS output represents, in UTC, and then the PPS pulse would give us the phase. The upside of this is that we get the date and time, but we don't get it adjusted to our local time-zone, we also depends strictly on the presence of the GPS signal. Also, the PPS pulse varies due to GPS properties as well as the clock-pulse assignment causing the sawtooth error. As widely known in the group, sawtooth error corrections is available over the serial interface from several receivers. Further, to make a more quiet source you want to filter out some of the GPS noise. This is where the Pulse Puppy can come at handy, as you can steer the oscillator with the GPS PPS pulse and sawtooth corrections, measure the time-difference and then create a servo-loop to steer the oscillators frequency and phase to an average of that from the GPS. The produced PPS pulse can be made more quiet for the short term stability while following the GPS long-term. In that regard we can filter and get a more stable clock. Another drawback may be that we loose GPS signal. There are many possible sources for that, but regardless which source, one needs to cover up the loss. This you do with hold-over, which is the secondary function of an oscillator. During hold-over the steering of the oscillator should be such that it minimize the time-error of a properly operating time and that of the clock in the oscillator. This is in it's most trivial form achieved by ensuring that the frequency steering of the oscillator is maintained as if it was locked to the GPS. The hold-over properties to a high degree depends on how well the oscillator is steered, and how stable the oscillator is to start with, but it ends being a material sport in that you go from TCXO, small OCXO, bigger OCXO, double-oven OCXO, rubidium clock, cesium clock etc. The GPS module has a small TCXO, but for these purposes you probably want to have something better. The digital clock part would at first look very trivial, it has a simple clock counter that counts 24 hours, 60 minutes and 60 seconds. OK, so we need to set this clock. Oh, we might have time-zones. Oh, we might have shifts to and from daylight savings. Oh, we might have leap-seconds. Already there we have a little bit of added complexity. Nothing that can't be handled thought. Also, we want to set the time from the GPS module, so that would require us to have a serial link just to get the NMEA data or similar at least. We probably want to get additional data to be warned about leap-seconds, get the UTC-GPS offset, GPS week number etc. A separate serial link would probably be useful to set time-zone data or set the time from another source, such as a computer timed with NTP. It may also be interesting to encode time to be sent out. Serial interface, IRIG-B or similar. Now, as we look at this, we cover quite a bit, and you can go into depths to do this better, as needed in professional needs. However, I also see a potential to teach several different concepts that comes together in a DIY project, which also may be very handy. If done with a little bit of care, we can teach proper terms to be scientific and educational in one end, while also being very hands on and useful in the other. At the same time we can "crash" into some of the challenges that the professional world sees, and also lots of people needs to be educated in too. Being hands on and simplified just makes it more concrete, rather than abstracts concepts. Could be very useful and educational for a wide audience. Once bitten by the time-nuts bug, there is many things to improve. Cheers, Magnus - both hobbyist and professional ------------------------------ Message: 3 Date: Sun, 24 Feb 2019 12:02:47 +0000 From: "Rice, Hugh (IPH Writing Systems)" <[email protected]> To: Discussion of precise time and frequency measurement <[email protected]> Subject: Re: [time-nuts] HP Stories: An architectural view of the HP 5060/5061 and awkward oscillator adjustments. Message-ID: <cs1pr8401mb10789ee2ac1462203afd86ed8c...@cs1pr8401mb1078.namprd84.prod.outlook.com> Content-Type: text/plain; charset=WINDOWS-1252 Several people have asked about the Len Cutler ban on Aluminum Electrolytic Capacitors in HP Frequency Standards. Rick Karlquist could shed more light on this too. The legend of the ban was passed along to me, perhaps by Lou Mueller, who liked to tell stories of the old days. In 1985, we were not taking the ban literally. For example, the 2400uF main power supply filter capacitor was AL-Electrolytic, as were a few other smaller capacitors on the power regulator. I sidestepped the capacitor issues on my simple battery charger by not having a filter cap after the transformer/full-wave-bridge, and just used 120 Hz pulses, since the battery didn't care about DC vs. pulsed DC. (I thought it was pretty clever to leave out the main filter cap.) Where possible, Tantalum capacitors were used. For the few places where AL caps were used, they were heavily de-rated, operating at 50% of rated voltage for example. As one reader pointed out, back in the 1965 when the 5060A was developed, AL-Electrolytic caps were likely a lot less reliable than in 1985 when I worked on the 5061B. From: time-nuts <[email protected]> On Behalf Of Rice, Hugh (IPH Writing Systems) Sent: Saturday, February 23, 2019 8:49 PM To: [email protected] Subject: [time-nuts] HP Stories: An architectural view of the HP 5060/5061 and awkward oscillator adjustments. Hello Time-Nuts, .... Stuff deleted ..... It was fantastically reliable. Only linear power circuits, with robust heat sinking of all power devices. The legendary Len Cutler ban on aluminum electrolytic capacitors. 5060s were still in use in 1985, after 20 years of constant operation. Likewise, 5061As were abundant in time standards for 25+ years until they were replaced by the 5071A in the 1990s. ------------------------------ Subject: Digest Footer _______________________________________________ time-nuts mailing list [email protected] http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com ------------------------------ End of time-nuts Digest, Vol 175, Issue 33 ****************************************** _______________________________________________ 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.
