| yantisj | Posted: 25 Oct 2026, 10:50 AM |
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 Member Posts: 2 Joined: 25-October 26 |
I’ve developed a precision time mesh over BLE (60ns RMS) and I’ve run into the Precision Clock looking for a display. I saw that it’s possible to use an external time reference but not sure how viable that is. I can output a 1PPS or 10Hz signal yet would probably have to connect to the STM for UTC/TZ transfer. Ideally I’d like to get the clock to join my time mesh which I created to extend my poor GPS signal to other devices already (one solid reception window in my location). This can be made to work with the wireless STM module as well but I don’t see that one here. nRF52/54 and ESP32 boards also work. Thoughts? More on the protocol here and it works with cheap LoRa mesh boards: https://ptob.dev Thanks, and I’m destined to own one of these either way. ------------- |
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| mit | Posted: 25 Oct 2026, 11:34 AM |
 yeah whatever Admin Posts: 704 Joined: 4-May 16 |
If the expectation is to completely replace the onboard GPS module, then you'll need to provide a PPS signal and NMEA serial data. The strings are quite easy to generate, you only need to provide the RMC message for the clock to accept it. There is a very basic script to generate the strings here: https://github.com/mitxela/PrecisionClockMkII/blob/master/nmea.py The time source should only output PPS if it's accurate. If reception is lost, PPS should stop pulsing. In general, most people who ask about replacing the GPS module are asking about feeding the clock from a fancy timesource like rubidium or better. In those cases, if you keep the GPS module powered and with reception, it would be enough to simply replace the PPS signal, as the two time sources would need to drift by about half a second to go out of sync. It's also possible to replace the 10MHz TCXO on the clock, but the only reason to ever do this is to improve holdover performance. Incidentally, if you want a clock without the GPS module fitted, I do have a couple of PCBs awaiting repair, where the GPS module failed to reflow correctly, so could potentially give you a discount. ------------- |
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| yantisj | Posted: 25 Oct 2026, 08:14 PM |
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Member Posts: 2 Joined: 25-October 26 |
That makes sense, and i should be able to extend that as well or at least emulate it for my location. PPS is easy enough, let me look into it thanks! ------------- |
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