Raspberry Pi

Commands

The vcgencmd is a command line utility from RaspbianOS, that can get various pieces of information from the VideoCore GPU on the Raspberry Pi.

$ vcgencmd

$ watch -n 1 vcgencmd measure_temp

Sources:

• vcgencmd
• RPI vcgencmd usage

Stopping SD Card Corruption on Raspberry Pi's Rasbian OS

Disable and remove swapfile

$ dphys-swapfile swapoff
$ dphys-swapfile uninstall
$ update-rc.d dphys-swapfile remove
$ apt purge dphys-swapfile

Set up tmpfs mounts

$ vim /etc/fstab
# Add the following line
none        /var/log        tmpfs   size=1M,noatime         00

Source:

• stopping sd card corruption on a raspberry pi

Configurations (RaspbianOS)

Enable WiFi

Place wpa_supplicant.conf in /boot/

Restart WiFi without reboot

$ sudo systemctl daemon-reload

$ sudo systemctl restart dhcpcd

Enable ssh on boot

Place an empty file (named ssh) in /boot/ to enable ssh access.

Example: /boot/ssh

Default ssh login to Pi (Raspbian):

• Username: pi
• Password: raspberry

$ ssh pi@<Raspberry Pi’s IP address>

With ssh key

$ ssh -i ~/.ssh/id_rsa pi@hostname

About config.txt (The system configuration parameters)

To control various settings of the OS and hardware, like fan speed and temperature.

Place config.txt in /boot/ to set configurations

Configurations (Ubuntu)

Enable WiFi on boot (Working)

Edit the network-config file in system-boot in boot drive, and add your Wi-Fi details.

Example config with IPv4 and IPv6 DHCP enabled:

network:
  version: 2
  renderer: networkd
  wifis:
    wlan0:
      dhcp4: true
      dhcp6: true
      optional: true
      access-points:
        "SSID":
          password: "PassPhrase"

Add the following to the end of the user-data file in system-boot in boot drive.

power_state:
  mode: reboot

Power on the PI and let neplan to initialize, after 5mins reboot the PI again and it will connect to the WiFi.

Update existing WiFi using netplan

Edit the /etc/netplan/50-cloud-init.yaml file, and add or change the following config:

# Example config with IPv4 and IPv6 DHCP enabled:
network:
  version: 2
  renderer: networkd
  wifis:
    wlan0:
      dhcp4: true
      dhcp6: true
      access-points:
        "SSID":
          password: "PassPhrase"

With static IPv4 address:

network:
  version: 2
  renderer: networkd
  wifis:
    wlan0:
      dhcp6: true
      addresses: [192.168.0.21/24]
      access-points:
        "SSID":
          password: "PassPhrase"

More configuration examples can be found here

Once done, generate, apply, systemctl daemon-reload, and reboot with the following commands:

• Generate: sudo netplan --debug generate (will give you more details in case of issues with the previous command)
• Apply: sudo netplan --debug apply
• Reload: sudo systemctl daemon-reload
• Reboot: sudo reboot

Default ssh login to Pi (Ubuntu):

• Username: ubuntu
• Password: ubuntu

$ ssh ubuntu@<Raspberry Pi’s IP address>

With ssh key

$ ssh -i ~/.ssh/id_rsa pi@hostname

Fan temperature

Display Raspberry Pi ARM CPU temperature

$ cat /sys/class/thermal/thermal_zone0/temp

$ cpu=$(</sys/class/thermal/thermal_zone0/temp)
$ echo "$((cpu/1000)) c"

Fan control and cooling

The fan config is in /sys/class/thermal/cooling_device0/, if you cat /sys/class/thermal/cooling_device0/type, it should be "rpi-poe-fan".

Once you've confirmed that, use this udev rule as an example:

SUBSYSTEM=="thermal"
KERNEL=="thermal_zone0"

# If the temp hits 70c, turn on the fan. Turn it off again when it goes back down to 65.
ATTR{trip_point_0_temp}="70000"
ATTR{trip_point_0_hyst}="2000"
#
# If the temp hits 75c, higher RPM.
ATTR{trip_point_1_temp}="75000"
ATTR{trip_point_1_hyst}="3000"
#
# If the temp hits 80c, higher RPM.
ATTR{trip_point_2_temp}="80000"
ATTR{trip_point_2_hyst}="4000"
#
# If the temp hits 85c, highest RPM.
ATTR{trip_point_3_temp}="85000"
ATTR{trip_point_3_hyst}="5000"

Place it in /etc/udev/rules.d/50-rpi-fan.rules

Discover the IP of your PI

ping

$ ping raspberrypi.local

nmap

$ nmap -sn 192.168.1.0/24

$ nmap -sn 192.168.1.0/24 | grep -B 2 B8:27:EB

$ arp -na | grep -i "b8:27:eb"

# Raspberry Pi 4
$ arp -na | grep -i "dc:a6:32"

OS update

$ sudo apt update --fix-missing -y && sudo apt dist-upgrade -y && sudo apt autoremove --purge -y