doc(location):Add html version of location README
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1 * Location Logging
2 This document was created by Steven Baltakatei Sandoval on
3 <2020-06-29 Mon 12:14> under a [[https://creativecommons.org/licenses/by-sa/4.0/][Creative Commons BY-SA 4.0 license]]. It
4 was updated by Steven Baltakatei Sandoval on <2020-06-29 Mon 22:06>.
5 #+TITLE: Ninfacyzga-01 Manual
6 #+AUTHOR: Steven Baltakatei Sandoval
7 #+DATE: 2020-06-29T22:16Z
8 #+EMAIL: baltakatei@gmail.com
9 ** Narrative
10 Ninfacyzga-01 records (logs) its position in time and space using a
11 [[https://en.wikipedia.org/wiki/Satellite_navigation_device][GPS receiver]]. The NMEA location data produced by the receiver is
12 converted into the more commonly used GPS data storage formats of GPX
13 and KML. All three types of data are then compressed and encrypted
14 against a set of public keys. The encrypted data is then written to
15 disk. Data produced by the receiver is segmented into 60-second chunks
16 before being processed and written to disk.
17 ** Description
18 *** Hardware
19 **** Raspberry Pi Zero W
20 See the [[https://www.raspberrypi.org/pi-zero-w/][OEM]] webpage for this product.
21 **** PiZ UpTime 2.0
22 See the [[https://alchemy-power.com/piz-uptime-2-0/][OEM]] webpage for this product.
23 *** Software
24 ~bkgpslog~ : The bash script that performs the location data
25 collection and processing. Is an executable file contained within this
26 repository at ~exec/bkgpslog~. It should be copied to
27 ~$HOME/.local/bin~.
28
29 ~gpsd~ : A background daemon app capable of interfacing with the
30 Ozzmaker BerryGPS-IMU's GPS submodule. Installed and initialized by
31 ~apt~.
32
33 ~gpspipe~ : A command line app that polls ~gpsd~ and produces a stream
34 stdout consisting of GPS data lines in NMEA format. Installed via
35 ~apt~.
36
37 ~gpsbabel~ : A command line app that converts GPS data from one format
38 into another. ~bkgpslog~ uses it to convert NMEA data into GPX and
39 KML. Installed via ~apt~.
40
41 ~gzip~ : A simple command line app that compresses stdin into a
42 smaller stdout stream.
43
44 ~age~ : A simple command line app that encrypts stdin against public
45 keys specified in its options. Produces encrypted stdout. Is an
46 executable file contained within this repository at ~exec/age~. It
47 should be copied to ~$HOME/.local/bin~.
48
49 **** Narrative
50 ~bkgpslog~ populates a 60-second buffer with NMEA data from ~gpsd~ via
51 ~gpspipe~. This buffer is used by ~gpsbabel~ to produce GPX and KML
52 versions of the buffer. All 3 buffers are then comprssed with ~gzip~,
53 encrypted with ~age~, and then written to disk.
54
55 *** Output
56 **** File Formats
57 ***** NMEA
58 See the [[https://en.wikipedia.org/wiki/NMEA_0183][Wikipedia page]] for this.
59 ***** GPX
60 See the [[https://en.wikipedia.org/wiki/GPS_Exchange_Format][Wikipedia page]] for this. [[http://wiki.gis.com/wiki/index.php/WGS84][WGS84]] is the datum used.
61 ***** KML
62 See the [[https://en.wikipedia.org/wiki/Keyhole_Markup_Language][Wikipedia page]] for this. [[http://wiki.gis.com/wiki/index.php/WGS84][WGS84]] is the datum used.
63 **** Encryption Method
64 Files produced by the bkgpslog script are encrypted against a set of
65 public keys using [[https://github.com/FiloSottile/age][~age~]], a simple command line encryption tool
66 selected over ~gpg~ because of ~age~'s deliberate lack of
67 configurability.
68
69 The public keys are bech32 strings supplied as options to bkgpslog
70 when called. The secret key should *NOT* be stored in Ninfacyzga-01.
71
72 If a key pair was generated using ~age-keygen~, then it is an [[https://en.wikipedia.org/wiki/Curve25519][~X25519~]]
73 key pair. See the [[https://age-encryption.org/v1][~age~ Version 1 specification]].
74
75 An ~ssh-rsa~ or ~ssh-ed25519~ SSH public key string may be used instead of
76 the bech32 public key string produced by ~age-keygen~ for convenience.
77
78 Help information for ~age~ is available by running ~$ age --help~.
79 ***** Encryption Commands
80 Files may be encrypted to several recipients using a command similar to:
81 #+BEGIN_EXAMPLE
82 timeout "60s" gpspipe -r | gpsbabel -i nmea -f - -o gpx -F | age \
83 -r age1kza7pfshy7xwygf9349zgmk7x53mquvedgw9r98qwyyqhssh830qqjzlsw \
84 -r age1ce3pvzrqfcn2pc6zqzglc8ac8yjk3fzukpy08cesqjjwns53xywqmaq7xw \
85 -r age1pu5usxm743sx7rf22985xv2f4s0luzv6r6yx4fa7p8c2zyvp9fvqus2xr5 \
86 > location.gpx.age
87 #+END_EXAMPLE
88
89 In this example, the strings beginning with ~age1...~ are
90 bech32-formatted public key strings.
91
92
93 ***** Decryption Commands
94 Files may be decrypted using a command similar to:
95
96 #+BEGIN_EXAMPLE
97 cat location.gpx.age | age -d -i key.txt > location.gpx
98 #+END_EXAMPLE
99
100 The version of ~age~ used to perform the encryption
101 ** Operating Procedures
102 *** Initial Startup
103 See OEM (Ozzmaker) [[https://ozzmaker.com/berrygps-berrygps-imu-quick-start-guide/][quickstart guide for the BerryGPS-IMU]].
104
105 **** Physical Setup
106
107 BerryGPS-IMU must be electrically connected to the correct pins on the
108 GPIO header of a Raspberry Pi Zero W.
109
110 *Optional*: stack together with PiZ Uptime 2.0 module. No GPIO pins
111 conflict so a simple stacking and soldering with long header pins is
112 possible.
113
114 **** Software Setup
115
116 ***** Install Executables
117
118 Install Raspbian 10 Buster onto an SD card image. See the Raspberry Pi
119 Foundation [[https://www.raspberrypi.org/documentation/installation/installing-images/README.md][installation instructions]]. Configure WiFi to permit log
120 file transfer. Configure SSH to permit remote administration via the
121 command line interface.
122
123 Make sure to install the ~unattended-upgrades~ package to make sure
124 the latest security patches for packages are installed. See [[https://linux-audit.com/using-unattended-upgrades-on-debian-and-ubuntu/][this page]]
125 for a description of how ~unattended-upgrades~ works.
126
127 Install ~gpsd~, ~gpspipe~, ~git~, and this repository for location
128 logging capability.
129
130 Install ~syncthing~ for log file transfer capability.
131
132 Place ~age~ binary (the one compiled for ARM CPU architecture for
133 Linux) in ~$HOME/.local/bin~.
134
135 ***** Automatic Start Configuration
136
137 Edit the user cron job list with ~$ crontab -e~ to add the following
138 lines:
139
140 #+BEGIN_EXAMPLE
141 0 * * * * /bin/bash ~/bkgpslog --output ~/dir
142
143 @reboot /bin/bash ~/bkgpslog --output ~/dir
144 #+END_EXAMPLE
145
146 The first line will run ~bkgpslog~ at the start of every hour and save
147 output files to the ~dir~ directory in your home folder.
148
149 The second line will run ~bkgpslog~ when the system starts up.
150
151 ~/bin/bash~ tells ~cron~ to run ~bkgpslog~ with Bash.
152
153 If encryption and compression are required, then the appropriate
154 options must be added. The lines that must be added via ~$ crontab -e~
155 may resemble:
156
157 #+BEGIN_EXAMPLE
158 0 * * * * /bin/bash ~/bkgpslog -c -e -r age1z2...qkv6p -o ~/dir
159
160 @reboot /bin/bash ~/bkgpslog -c -e -r age1z2...qkv6p -o ~/dir
161 #+END_EXAMPLE
162
163 The ~age1z2...qkv6p~ is an ~age~ public key string. Please see the
164 [[*Key Generation][Key Generation]] section for an explanation.
165
166 The options are:
167
168 : -c : tells bkgpslog to compress output
169 : -e : tells bkgpslog log to encrypt output
170 : -r : tells bkgpslog to interpret the next argument as a pubkey string
171 : -o : tells bkgpslog to write output files to the directory represented
172 : by the next argument
173
174 ***** Log Transfer Configuration
175 Log files may be shared to other machines via ~syncthing~. See [[https://docs.syncthing.net/][this]]
176 manual for how to set up a shared folder and add Ninfacyzga-01 as a
177 device. Syncthing's directory synchronization capability allows a
178 remote machine to delete files from Ninfacyzga-01 by deleting from the
179 shared folder that they both share.
180
181 When log files are removed from Ninfacyzga-01 is not within the scope
182 of this document.
183
184 ***** Key Generation
185 An ~age~ encryption key may be generated like so:
186 #+BEGIN_EXAMPLE
187 $ umask # Gets current umask
188 0022 # Note: This is the default umask for Raspbian 10
189 $ umask 066 # Sets umask so key.txt will have no permissions except for owner (you)
190 $ umask # Confirm umask set to 066
191 0066
192 $ age-keygen > key.txt
193 Public key: age1pu5usxm743sx7rf22985xv2f4s0luzv6r6yx4fa7p8c2zyvp9fvqus2xr5
194 $ ls -al key.txt
195 -rw------- 1 baltakatei baltakatei 184 Jun 29 18:28 key.txt
196 $ umask 0022 # Return umask to default value
197 $ umask
198 0022
199 #+END_EXAMPLE
200
201 The resulting public/private keypair data looks like:
202 #+BEGIN_EXAMPLE
203 $ cat key.txt
204 # created: 2020-06-29T18:01:56Z
205 # public key: age1pu5usxm743sx7rf22985xv2f4s0luzv6r6yx4fa7p8c2zyvp9fvqus2xr5
206 AGE-SECRET-KEY-1NEUU5U2XGZGL9UYWNPU5DL99TGJJHFSN4F2E2WCCSDJJ6L5ZMLESNTVTU0
207 #+END_EXAMPLE
208
209 The file ~key.txt~ is not password-protected by default and should be
210 secured like an SSH public key should. The ~$ umask 066~ command run
211 before the ~$ age-keygen > key.txt~ command ensures ~key.txt~ will not
212 be readable, writeable, or executable to anyone except the owner
213 (you).
214
215 *** Normal Startup
216 Turn on Ninfacyzga-01 by supplying 5VDC power to the Raspberry Pi. No
217 further interaction should be required.
218 *** Normal Operation
219 No interaction beyond continually supplying approximately 100mA of
220 5VDC power and occasionally removing log files to conserve disk space
221 is required.
222 **** Log Transfer
223 Log files may be transferred by use of ~syncthing~ shared folders.
224 **** Automatic Updates
225 The ~automatic-upgrades~ package, if installed, should automatically
226 install security patches to packages installed via ~apt~.
227 *** Normal Shutdown
228 The system may be shutdown via SSH by running:
229
230 : $ sudo shutdown -r 0
231
232 *** Unscheduled Shutdown
233 Ninfacyzga-01 as described and setup should tolerate unscheduled power
234 loss. Log files being written every 60 seconds means, at most, 60
235 seconds worth of location data may be lost.
236 *** End of Life Disposal
237 LiPo batteries used by the PiZ Uptime 2.0 module should be disposed of
238 properly with their potential ignitability in mind, especially if they
239 are not fully discharged.
240
241 Consult your local municipality for its "E-Waste Disposal" (or
242 equivalent) policy. Metals used in the Raspberry Pi and related
243 components may be recycled.
244
245 Take extra precuation if lead solder was used in assembling the
246 electronics. Consumer electronics in early 21st century should use
247 lead-free solder.
248