From 6bdc24738d0318b034321bfdd9cff783a73664d4 Mon Sep 17 00:00:00 2001 From: Steven Baltakatei Sandoval Date: Sat, 25 Jul 2020 19:35:07 +0000 Subject: [PATCH] doc(time):Create README for time server setup Start documentation process for making `ninfacyzga-01` a time server that uses satellite GPS data. --- README.org | 3 ++- doc/time/README.org | 55 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+), 1 deletion(-) create mode 100644 doc/time/README.org diff --git a/README.org b/README.org index d2f47a6..7dbe360 100644 --- a/README.org +++ b/README.org @@ -2,7 +2,7 @@ ** Introduction This document created by Steven Baltakatei Sandoval on 2020-06-07T21:56Z under a [[http://creativecommons.org/licenses/by-sa/4.0/][CC BY-SA 4.0]] license and last updated on -2020-07-16T00:37Z. +2020-07-23T22:26Z. ** Abstract This git repository contains software and documentation necessary to set up a sensor package for logging observables in the local @@ -11,6 +11,7 @@ environment. Collected sensor data include: - Location (GPS WGS84) +- Time (via ~gpsd~) - Air Pressure (pascals) - Alignment (degrees X, degrees Y, degrees from magnetic north) diff --git a/doc/time/README.org b/doc/time/README.org new file mode 100644 index 0000000..b346b3b --- /dev/null +++ b/doc/time/README.org @@ -0,0 +1,55 @@ +* Time +This document was created by Steven Baltakatei Sandoval on +~2020-07-23T22:27Z~ under a [[https://creativecommons.org/licenses/by-sa/4.0/][Creative Commons BY-SA 4.0 license]]. It +was updated by Steven Baltakatei Sandoval on ~2020-07-25T19:34Z~ +** Development Task list +*** Set up prototype unit +**** Solder wire for PPS signal +**** Follow guide +- [[https://ozzmaker.com/forums/topic/connecting-gps-pps-pin/][Ozzmaker post]] on ~PPS~ wiring and a [[https://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html][guide]] recommendation. +- [[http://www.satsignal.eu/raspberry-pi/Schmidt-RPZ-NTP-2016.pdf][Schmidt article]] on Raspberry Pi Zero time server. +- [[https://gpsd.gitlab.io/gpsd/gpsd-time-service-howto.html][GPSD dev ref]] page for ~gpsd~ interfacing with ~ntp~. +*** Document prototype unit +** Narrative +The ~ninfacyzga-01~ device is equipped with an Ozzmaker BerryGPS-IMU +module which provides time and location data to ~gpsd~. The time is +provided by GPS satellites which themselves are [[https://science.nasa.gov/science-news/science-at-nasa/2002/08apr_atomicclock/][equipped]] with atomic +clocks. This extremely accurate set of clocks are needed since a GPS +receiver calculates its position in space using a General Relativity +calculation that uses the small variations in the time stamps received +from each satellite. This means that ~gpsd~ may be used to set the +system clock without a need for an internet connection to a default +Debian time server; ~ninfacyzga-01~ can be its own time server. +** Description +*** Hardware +Ozzmaker BerryGPS-IMU, Version 3 +*** Software +This guide describes steps that may be used to convert a Raspberry Pi +into a time server using ~gpsd~. +** Operating Procedures +*** Initial Startup +**** Install Raspbian 10 (Buster) onto a Raspberry Pi Zero W. +**** Install Hardware +See [[https://ozzmaker.com/forums/topic/connecting-gps-pps-pin/][this]] Ozzmaker forum topic about connecting the BerryGPS-IMU +~T_PULSE~ pin to GPIO 18. + +Connect the ~T_PULSE~ connection on the BerryGPS-IMU-3 to GPIO pin 18 +in order to enable ~gpsd~ to read the PPS signal for forwarding to +~ntp~. + +**** Install Software +Run the following command to install the required packages. +: $ sudo apt install usbmount eject gpsd gpsd-clients python-gps pps-tools ntp + +These instructions assume that ~gpsd~ has already been setup to +provide NMEA sentences to ~gpspipe~ for location. See the ~README.org~ +in ~doc/location~ for details. Basically, ~gpsd~ needs to be told via +its ~/etc/default/gpsd~ configuration file of which ~/dev/tty???~ will +provide the raw GPS module data. + +*** Normal Startup +*** Normal Operation +*** Normal Shutdown +*** Unscheduled Shutdown + + -- 2.30.2