quick-pi

Tools to enable programming a Raspberry Pi from the QuickAlgo environment

How to setup

• Download the latest Raspbian Buster Lite (no GUI needed) version from https://www.raspberrypi.org/downloads/raspbian/, follow the instructions on how to write the image to an SD card here https://www.raspberrypi.org/documentation/installation/installing-images/README.md.

• If you are planing to make this a production ready image reinsert the SD card into the machine you used to write it and go to the drive. You will find a cmdline.txt file. Open it and delete init=/usr/lib/raspi-config/init_resize.sh from the end of the command line. This will prevent the filesystem to be resized to fill the whole size of your sd card.

• Boot the Raspberry Pi (connect a keyboard and display), login with the default pi/raspbian user password.

• Create a 100M partition after the root partition to store the installed program (the root partition is read only):

echo -e "n\n\n\n4292608\n+100M\nw\nq\n" | fdisk /dev/mmcblk0
partprobe

mkfs.ext4 /dev/mmcblk0p3
mkdir /mnt/data
chown pi.pi /mnt/data/
echo "/dev/mmcblk0p3 /mnt/data ext4 defaults 0 2" >> /etc/fstab

• Run sudo raspi-config and enable SSH (for easier remote management and setup WiFi), also enable I2C (Needed for analog sensors).

• Install the required dependencies by doing: sudo apt-get install python3-flask python3-pip python3-rpi.gpio gunicorn3 dos2unix python3-pexpect python3-smbus pigpio python3-pigpio bluez-tools dnsmasq bridge-utils python3-pil hostapd

then: sudo pip3 install flask-cors Flask-Sockets luma.oled adafruit-circuitpython-vl53l0x.

also: sudo systemctl enable pigpiod

and: sudo systemctl unmask hostapd

• Copy the contents of the server directory into /home/pi/quickpi/ in the Raspberry Pi using scp. This is a flask webapp that will run the programs in the Raspberry Pi.

How to create a production ready image

First run all of the above steps then:

• Add dtoverlay=dwc2,dr_mode=peripheral to the bottom of /boot/config.txt

• Add modules-load=dwc2,g_ether in /boot/cmdline.txt right next to rootwait. Don't introduce new lines into this file.

• Edit /lib/systemd/system/pigpiod.service to change pigpiod command line to the following /usr/bin/pigpiod -n 127.0.0.1 -l -m -x -1

• Add the following command to /etc/rc.local:

/home/pi/quickpi/scripts/start.sh &

• Edit the file /lib/systemd/system/raspberrypi-net-mods.service so it look like this:

[Unit]
Description=Copy user wpa_supplicant.conf
Before=dhcpcd.service
After=systemd-rfkill.service

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/home/pi/quickpi/scripts/setupwifi.sh
ExecStartPost=/bin/chmod 600 /etc/wpa_supplicant/wpa_supplicant.conf
ExecStartPost=/usr/sbin/rfkill unblock wifi

[Install]
WantedBy=multi-user.target

• Delete the wpa_supplicant config file and link it to /tmp like with these commands:

rm /etc/wpa_supplicant/wpa_supplicant.conf
ln -s /tmp/wpa_supplicant.conf /etc/wpa_supplicant/wpa_supplicant.conf

• Move the dhcpcd config and link it to /tmp:

mv /etc/dhcpcd.conf /etc/dhcpcd.conf.template
ln -s /tmp/dhcpcd.conf /etc/dhcpcd.conf

Same with hostapd config file:

rm -f /etc/hostapd/hostapd.conf 
ln -s /tmp/hostapd.conf /etc/hostapd/hostapd.conf

• Add the following to the bottom of /etc/dhcpcd.conf.template

interface usb0
static ip_address=192.168.233.1

interface pan0
static ip_address=192.168.233.2

denyinterfaces ap0
interface ap0
nohook wpa_supplicant

• Edit /etc/dnsmasq.conf so that this is the entiere contents:

interface=usb0
interface=ap0
interface=pan0
dhcp-range=192.168.233.10,192.168.233.230,2h
dhcp-option=usb0,3
dhcp-option=usb0,6
address=/#/192.168.233.3

• Edit /etc/default/dnsmasq to add at the bottom:

DNSMASQ_EXCEPT=lo

• Delete /var/lib/ and link it to /tmp

rm -rf /var/lib/misc
ln -s /tmp /var/lib/misc 

• Create a dummy quickpi.txt file in /boot with the following contents:

SSID=wifiname
PASSWORD=wifipassword
STATICNETWORK=1
STATICIPADDR=192.168.1.31
STATICGATEWAY=192.168.1.1
STATICDNS=8.8.8.8

NAME=quickpi1
SCHOOL=schoolkey
SCHOOLPASSWORD=schoolpassword

• Download Adafruit script to make the filesystem readonly: wget https://raw.githubusercontent.com/adafruit/Raspberry-Pi-Installer-Scripts/master/read-only-fs.sh; sudo bash read-only-fs.sh. Answer N to "Enable boot-time jumper", "Install GPIO-halt utility" and Enable kernel panic watchdog so none of those is enabled.

• Shutdown the Raspberry Pi using sudo halt. Remove the raspberry pi and take an image of the SD card of the same size plus 100M (add a bit to be sure) of the original Raspbian Image you started with.