[time-nuts] Lowest Power NTP Server

[Bob kb8tq]

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 at 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 at gmail.com <mailto:tshoppa at 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 at n1k.org <mailto:kb8tq at 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
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