Add additional Raspberry Pi setup instructions to fix iRobotEducation/create3_examples#44 (#428)

* Add additional setup that fixes iRobotEducation/create3_examples#44
* Fix and cleanup ntp documentation steps
* Fix chrony.conf instructions - a server does not need to be added
* Add steps for adding the raspi to the Create 3's NTP sources
* Remove an extraneous line and a reference to connecting over USB to the web interface.
* Add recommendation to follow NTP setup and make adding NTP sources an optional step
 Addresses iRobotEducation/create3_examples#44
* Add note to only add compute board IP address to Create 3 NTP sources if it is missing

Author: ChrisBove

docs/setup/compute-ntp.md

@@ -22,7 +22,6 @@ If your Create® 3 and compute board have an internet connection, this is not re
 
 1. Add the following lines after the `pool #.ubuntu.pool.ntp.org iburst maxsources #` block
 
-        server 192.168.186.2 presend 0 minpoll 0 maxpoll 0 iburst  prefer trust
         # Enable serving time to ntp clients on 192.168.186.0 subnet.
         allow 192.168.186.0/24
 
@@ -35,6 +34,12 @@ If your Create® 3 and compute board have an internet connection, this is not re
 
         sudo service chrony restart
 
+1. Log into the Create® 3 web application and modify the NTP sources (as of Jul 2023 under "Beta Features") to add the following if it does not exist: 
+
+        server 192.168.186.3 iburst
+
+1. Through the Create® 3 web application, restart the NTPD server (or reboot the robot) if you made changes in the previous step.
+
 1. Verify compute NTP server is talking to the Create® 3
 
         sudo chronyc clients
@@ -44,12 +49,11 @@ If your Create® 3 and compute board have an internet connection, this is not re
         Hostname                      NTP   Drop Int IntL Last     Cmd   Drop Int  Last
         ===============================================================================
         192.168.186.2                  51      0   5   -    32       0      0   -     -
-        localhost                       0      0   -   -     -      31      0   7     4
 
 1. Note that if there is a large jump in the time, the Create® 3 may not accept it until its next reboot.
     This can be verified by checking the Create® 3 robot's log for a line like
 
         user.notice ntpd: ntpd: reply from 192.168.186.3: delay ### is too high, ignoring
-    If this happens, simply restart the robot (not just the application) via the webserver over the USB network connection.
+    If this happens, simply restart the robot (not just the application) via the webserver over the network connection.
 
 [^1]: ROS 2 is governed by Open Robotics

docs/setup/pi4galactic.md

@@ -37,6 +37,13 @@ The first boot may take a few minutes. (It may help to have a monitor and keyboa
         sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8
         export LANG=en_US.UTF-8
 
+1. Recommended: follow the procedure to [Setup NTP on this compute board](compute-ntp.md) so the Create 3 can sync its clock.
+2. Optional: Run `timedatectl` and see if `System clock synchronized: ` says `yes`. If not, you may want setup NTP on your raspi so the clock stays accurate. To do so, specify some NTP servers for time syncronization. Edit `/etc/systemd/timesyncd.conf` (`sudo nano /etc/systemd/timesyncd.conf`) to have the below contents, then run `systemctl restart systemd-timesyncd.service` to load the new NTP server configuration. 
+
+        [Time]
+        NTP=ntp.ubuntu.com
+        FallbackNTP=0.us.pool.ntp.org 1.us.pool.ntp.org
+
 1. Then, execute the following blocks of commands to install ROS 2[^4]:
 
         sudo apt update && sudo apt install -y curl gnupg2 lsb-release build-essential git cmake

docs/setup/pi4humble.md

@@ -60,6 +60,13 @@ The first boot may take a few minutes. (It may help to have a monitor and keyboa
         sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8
         export LANG=en_US.UTF-8
 
+1. Recommended: follow the procedure to [Setup NTP on this compute board](compute-ntp.md) so the Create 3 can sync its clock.
+2. Optional: Run `timedatectl` and see if `System clock synchronized: ` says `yes`. If not, you may want setup NTP on your raspi so the clock stays accurate. To do so, specify some NTP servers for time syncronization. Edit `/etc/systemd/timesyncd.conf` (`sudo nano /etc/systemd/timesyncd.conf`) to have the below contents, then run `systemctl restart systemd-timesyncd.service` to load the new NTP server configuration.
+
+        [Time]
+        NTP=ntp.ubuntu.com
+        FallbackNTP=0.us.pool.ntp.org 1.us.pool.ntp.org
+
 1. Then, execute the following blocks of commands to install ROS 2[^4]:
 
         sudo apt update && sudo apt install -y curl gnupg2 lsb-release build-essential git cmake