From: Steven Baltakatei Sandoval <baltakatei@gmail.com>
Date: Sat, 25 Jul 2020 19:35:07 +0000 (+0000)
Subject: doc(time):Create README for time server setup
X-Git-Url: https://zdv2.bktei.com/gitweb/EVA-2020-02.git/commitdiff_plain/6bdc24738d0318b034321bfdd9cff783a73664d4

doc(time):Create README for time server setup

Start documentation process for making `ninfacyzga-01` a time server
that uses satellite GPS data.
---

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
+
+