Hi If you are going to run the beast on batteries, and talk to it via WiFi, what’s the lowest power NTP server you can build? Timing source to keep it under a few ms would have to be included. GPS seems to be a reasonable choice. So far this seems to be the leading contender: https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50 <https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50> Same paper at a different URL (thanks to TVB): https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf <https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf> Best guess is that it comes in around 0.5W. That is just a guess based on: https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications <https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications> and not (yet) a measured number. Application is for off grid / remote / out of cell coverage timing of various “stuff”. Power is from a battery so fractions of a watt do count. More or less, 0.5W on a 5AH 12V battery runs for 120 hours. Something at 5W only runs for 12 hours ….. Bob

-------- You can do better than RPi, since a NTP server basically only needs to understand two packets: IP/UDP at port 123 and ARP packets. There are WiFi enabled microcontrollers that could be taught how to do that, but you'd have to write up your NTP daemon from scratch which is not hard when you do not have to do the "sync clock from remote servers" part. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.

ESP8266 as a simple UDP server is 50mA * 3.3V = 0.17W. Tim N3QE On Sun, Dec 1, 2019 at 12:22 PM Bob kb8tq <kb8tq@n1k.org> wrote: > Hi > > If you are going to run the beast on batteries, and talk to it via WiFi, > what’s the lowest power > NTP server you can build? Timing source to keep it under a few ms would > have to be included. > GPS seems to be a reasonable choice. > > So far this seems to be the leading contender: > > > https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50 > < > https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50 > > > > Same paper at a different URL (thanks to TVB): > > https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf < > https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf> > > Best guess is that it comes in around 0.5W. That is just a guess based on: > > > https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications > < > https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications > > > > and not (yet) a measured number. > > Application is for off grid / remote / out of cell coverage timing of > various “stuff”. Power is from > a battery so fractions of a watt do count. More or less, 0.5W on a 5AH > 12V battery runs for > 120 hours. Something at 5W only runs for 12 hours ….. > > Bob > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

Hi So something like one of the many ESP32 based boards? Of course when it comes to the “code from scratch” part there is the problem that I’m pretty (most would say very …) lazy :) :) :) Bob > On Dec 1, 2019, at 12:29 PM, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote: > > -------- > > You can do better than RPi, since a NTP server basically > only needs to understand two packets: IP/UDP at port 123 > and ARP packets. > > There are WiFi enabled microcontrollers that could be taught how > to do that, but you'd have to write up your NTP daemon from scratch > which is not hard when you do not have to do the "sync clock from > remote servers" part. > > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > phk@FreeBSD.ORG | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence.

Hi I guess one *could* claim that this: https://github.com/DennisSc/PPS-ntp-server <https://github.com/DennisSc/PPS-ntp-server> Sort of eliminates my “to lazy to code it up from scratch” issue ….. So, the ESP’s seem to be in the 50 to 70 ma range depending on which one you look at. The GPS module is pretty close to that ( again depending on which one you use). A total of 100 ma at 3.3V seems like a good guess. With a good RTC, you might be able to power cycle the GPS …. Is there something better than this? Bob > On Dec 1, 2019, at 12:43 PM, Tim Shoppa <tshoppa@gmail.com> wrote: > > ESP8266 as a simple UDP server is 50mA * 3.3V = 0.17W. > > Tim N3QE > > On Sun, Dec 1, 2019 at 12:22 PM Bob kb8tq <kb8tq@n1k.org> wrote: > >> Hi >> >> If you are going to run the beast on batteries, and talk to it via WiFi, >> what’s the lowest power >> NTP server you can build? Timing source to keep it under a few ms would >> have to be included. >> GPS seems to be a reasonable choice. >> >> So far this seems to be the leading contender: >> >> >> https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50 >> < >> https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50 >>> >> >> Same paper at a different URL (thanks to TVB): >> >> https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf < >> https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf> >> >> Best guess is that it comes in around 0.5W. That is just a guess based on: >> >> >> https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications >> < >> https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications >>> >> >> and not (yet) a measured number. >> >> Application is for off grid / remote / out of cell coverage timing of >> various “stuff”. Power is from >> a battery so fractions of a watt do count. More or less, 0.5W on a 5AH >> 12V battery runs for >> 120 hours. Something at 5W only runs for 12 hours ….. >> >> Bob >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

Hi Digging into this: https://kb.meinbergglobal.com/kb/time_sync/ntp/configuration/ntp_broadcast_mode <https://kb.meinbergglobal.com/kb/time_sync/ntp/configuration/ntp_broadcast_mode> and the “deep sleep” power savings modes on the ESP32, it appears that one *could* do a once a minute / hour / day :) broadcast approach that would get the current in the server down to practically nothing. (and work with very simple code) At this point, I’m not quite ready to head off in that direction. I’d like to keep this a client / server mode approach. My main concern is that the clients are likely to be a bit “time challenged” and some of them could need fairly high update rates. (sorry for the double post ….) Bob > On Dec 1, 2019, at 1:21 PM, Bob kb8tq <kb8tq@n1k.org> wrote: > > Hi > > I guess one *could* claim that this: > > https://github.com/DennisSc/PPS-ntp-server <https://github.com/DennisSc/PPS-ntp-server> > > Sort of eliminates my “to lazy to code it up from scratch” issue ….. > > So, the ESP’s seem to be in the 50 to 70 ma range depending on which one > you look at. The GPS module is pretty close to that ( again depending on which > one you use). A total of 100 ma at 3.3V seems like a good guess. With a good > RTC, you might be able to power cycle the GPS …. > > Is there something better than this? > > Bob > > >> On Dec 1, 2019, at 12:43 PM, Tim Shoppa <tshoppa@gmail.com <mailto:tshoppa@gmail.com>> wrote: >> >> ESP8266 as a simple UDP server is 50mA * 3.3V = 0.17W. >> >> Tim N3QE >> >> On Sun, Dec 1, 2019 at 12:22 PM Bob kb8tq <kb8tq@n1k.org <mailto:kb8tq@n1k.org>> wrote: >> >>> Hi >>> >>> If you are going to run the beast on batteries, and talk to it via WiFi, >>> what’s the lowest power >>> NTP server you can build? Timing source to keep it under a few ms would >>> have to be included. >>> GPS seems to be a reasonable choice. >>> >>> So far this seems to be the leading contender: >>> >>> >>> https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50 <https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50> >>> < >>> https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50 >>>> >>> >>> Same paper at a different URL (thanks to TVB): >>> >>> https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf < >>> https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf> >>> >>> Best guess is that it comes in around 0.5W. That is just a guess based on: >>> >>> >>> https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications >>> < >>> https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications >>>> >>> >>> and not (yet) a measured number. >>> >>> Application is for off grid / remote / out of cell coverage timing of >>> various “stuff”. Power is from >>> a battery so fractions of a watt do count. More or less, 0.5W on a 5AH >>> 12V battery runs for >>> 120 hours. Something at 5W only runs for 12 hours ….. >>> >>> Bob >>> _______________________________________________ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe, go to >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >>> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com <mailto:time-nuts@lists.febo.com> >> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com <http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com> >> and follow the instructions there. >

I'd think one of the ESP32's would be a fine choice. They have some good power management options to wake up periodically to do the work, making for even lower power consumption. Looks like someone has already written some code that could be adapted? https://github.com/DennisSc/PPS-ntp-server/blob/master/README.md -David -------- Original Message -------- On Dec 1, 2019, 09:49, Bob kb8tq wrote: > Hi > > So something like one of the many ESP32 based boards? > > Of course when it comes to the “code from scratch” part there is the problem that I’m > pretty (most would say very …) lazy :) :) :) > > Bob > >> On Dec 1, 2019, at 12:29 PM, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote: >> >> -------- >> >> You can do better than RPi, since a NTP server basically >> only needs to understand two packets: IP/UDP at port 123 >> and ARP packets. >> >> There are WiFi enabled microcontrollers that could be taught how >> to do that, but you'd have to write up your NTP daemon from scratch >> which is not hard when you do not have to do the "sync clock from >> remote servers" part. >> >> >> -- >> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 >> phk@FreeBSD.ORG | TCP/IP since RFC 956 >> FreeBSD committer | BSD since 4.3-tahoe >> Never attribute to malice what can adequately be explained by incompetence. > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there.

On 12/1/19 7:47 AM, Bob kb8tq wrote: > Hi > > If you are going to run the beast on batteries, and talk to it via WiFi, what’s the lowest power > NTP server you can build? Timing source to keep it under a few ms would have to be included. > GPS seems to be a reasonable choice. Have you looked at Arduino? THere might be a NTP server implementation for Arduino, and in general, Arduinos are lower power. A lot would be determined by which WiFi interface you use. Another possibility is the Beaglebone Green Wireless - it has WiFi on board, ARM processor, etc. and runs Linux. I've run ntpd with a uBlox-7 (I think) GPS receiver on these. Since it doesn't have the HDMI video interface that the Beagle does, it might be lower power. I might have some measurements of the green wireless. > > So far this seems to be the leading contender: > > https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50 <https://www.researchgate.net/publication/332543537_BUILDING_A_RASPBERRY_PI_ZERO-W_GPS_NETWORK_TIME_SERVER_FOR_UNDER_50> > > Same paper at a different URL (thanks to TVB): > > https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf <https://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf> > > Best guess is that it comes in around 0.5W. That is just a guess based on: > > https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications <https://raspberry-projects.com/pi/pi-hardware/raspberry-pi-zero/raspberry-pi-zero-hardware-general-specifications> > > and not (yet) a measured number. > > Application is for off grid / remote / out of cell coverage timing of various “stuff”. Power is from > a battery so fractions of a watt do count. More or less, 0.5W on a 5AH 12V battery runs for > 120 hours. Something at 5W only runs for 12 hours ….. > > Bob > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >

On 12/1/19 9:29 AM, Poul-Henning Kamp wrote: > -------- > > You can do better than RPi, since a NTP server basically > only needs to understand two packets: IP/UDP at port 123 > and ARP packets. > > There are WiFi enabled microcontrollers that could be taught how > to do that, but you'd have to write up your NTP daemon from scratch > which is not hard when you do not have to do the "sync clock from > remote servers" part. There's also a GPS that incorporates a LEON SPARC microcontroller, and you could load up RTEMS which has the network stack. > >

You should look at latency. The ESP8266 has serial (SPI) flash and a relatively small internal cache. When the chip needs to load code from flash, that can take a while, compared to the 5uS target. Great for cheap IoT stuff, not so great for time sensitive, in my opinion. On Sun, Dec 1, 2019 at 2:01 PM David <david@mju.io> wrote: > I'd think one of the ESP32's would be a fine choice. They have some good > power management options to wake up periodically to do the work, making for > even lower power consumption. > > Looks like someone has already written some code that could be adapted? > > https://github.com/DennisSc/PPS-ntp-server/blob/master/README.md > > -David > > -------- Original Message -------- > On Dec 1, 2019, 09:49, Bob kb8tq wrote: > > > Hi > > > > So something like one of the many ESP32 based boards? > > > > Of course when it comes to the “code from scratch” part there is the > problem that I’m > > pretty (most would say very …) lazy :) :) :) > > > > Bob > > > >> On Dec 1, 2019, at 12:29 PM, Poul-Henning Kamp <phk@phk.freebsd.dk> > wrote: > >> > >> -------- > >> > >> You can do better than RPi, since a NTP server basically > >> only needs to understand two packets: IP/UDP at port 123 > >> and ARP packets. > >> > >> There are WiFi enabled microcontrollers that could be taught how > >> to do that, but you'd have to write up your NTP daemon from scratch > >> which is not hard when you do not have to do the "sync clock from > >> remote servers" part. > >> > >> > >> -- > >> Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > >> phk@FreeBSD.ORG | TCP/IP since RFC 956 > >> FreeBSD committer | BSD since 4.3-tahoe > >> Never attribute to malice what can adequately be explained by > incompetence. > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. >