Tag: raspberrypi

boot order – Raspbery pi

  • Edit boot order(read from right to left)
rpi-eeprom-config -e
ValueModeDescription
0x0SD CARD DETECTTry SD then wait for card-detect to indicate that the card has changed – deprecated now that 0xf (RESTART) is available.
0x1SD CARDSD card (or eMMC on Compute Module 4).
0x2NETWORKNetwork boot – See Network boot server tutorial
0x3RPIBOOTRPIBOOT – See usbboot
0x4USB-MSDUSB mass storage boot – See USB mass storage boot
0x5BCM-USB-MSDUSB 2.0 boot from USB Type C socket (CM4: USB type A socket on CM4IO board). Not available on Raspberry Pi 5.
0x6NVMECM4 and Pi 5 only: boot from an NVMe SSD connected to the PCIe interface. See NVMe boot for more details.
0x7HTTPHTTP boot over ethernet. See HTTP boot for more details.
0xeSTOPStop and display error pattern. A power cycle is required to exit this state.
0xfRESTARTRestart from the first boot-mode in the BOOT_ORDER field i.e. loop

boot order: https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#BOOT_ORDER

Raspberry Pi Max current with GPIO for LED

Note: withdrawing more current(~15mA) from GPIO can affect the Rpi
https://raspberrypi.stackexchange.com/questions/9298/what-is-the-maximum-current-the-gpio-pins-can-output

  • Use 5V Pin (2,4)
  • Use GPIO as Negative volt
  • Max current withdrawn was 23mA for my use case
import RPi.GPIO as GPIO
from time import sleep 
import sys

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BCM)
GPIO.setup(21, GPIO.OUT, initial=GPIO.HIGH)

if sys.argv[1] == "on":
    GPIO.output(21, GPIO.LOW)
    #print("on")
    exit()

Fore More brightness:

  • Add multiple GPIO as GROUND
  • After adding GPIO20 as ground it was taking ~18mA from GPIO20
  • And Overall of ~36mA from both GPIO 20 and 21

rapsberry pi camera on ubuntu

  • see if camera attached to raspberry pi yo will see something like bcm2835-v4l2: V4L2 device registered as video0 – stills mode > 1280×720
root@lp-arm-4:~# dmesg  | grep -i vid
--More--
[   13.071843] bcm2835-isp bcm2835-isp: Device node output[0] registered as /dev/video13
[   13.615235] bcm2835-isp bcm2835-isp: Device node capture[0] registered as /dev/video14
[   13.615709] bcm2835-isp bcm2835-isp: Device node capture[1] registered as /dev/video15
[   13.616053] bcm2835-isp bcm2835-isp: Device node stats[2] registered as /dev/video16
[   13.626826] bcm2835-codec bcm2835-codec: Device registered as /dev/video10
[   13.631504] bcm2835-codec bcm2835-codec: Device registered as /dev/video11
[   13.667772] : bcm2835_codec_get_supported_fmts: port has more encoding than we provided space for. Some are dropped.
[   13.702795] bcm2835-v4l2: V4L2 device registered as video0 - stills mode > 1280x720
[   13.708226] bcm2835-v4l2: Broadcom 2835 MMAL video capture ver 0.0.2 loaded.
[   13.744213] bcm2835-codec bcm2835-codec: Device registered as /dev/video12

--More--
  • install raspistill binary 
apt install libraspberrypi-bin
  • check camera status
vcgencmd get_camera
  • Removing and adding back sunny connector(the yellow thingy below the camera in the board) worked. (very strange)

https://stackoverflow.com/questions/31354280/raspberry-camera-error-mmal-no-data-received-from-sensor

32 GB SD card issue

One of the issue that i face with my raspberry pi 4 SD card. I removed it when it was in the pi case. Which broke the SD card chip in half internally.

Lesson : Always remove the SD carefully.

broke my 32 GB SD card while removing from Pi. I tried formatting with fdisk, mkfs.ext4 and Windows but none of them worked.

I have attached screenshot of fdisk /dev/sda where I have created 1 partition but when i try to delete the same it’s giving error No partition is defined yet!

https://i.stack.imgur.com/rRVNJ.png

Here is the lsblk output:

root@lp-arm-1:~# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
loop0         7:0    0 88.1M  1 loop /snap/core/11803
loop1         7:1    0 48.9M  1 loop /snap/core18/2127
loop2         7:2    0   49M  1 loop /snap/core18/2248
loop3         7:3    0 57.4M  1 loop /snap/core20/1171
loop4         7:4    0 88.1M  1 loop /snap/core/11996
loop5         7:5    0 60.4M  1 loop /snap/lxd/21544
loop6         7:6    0 28.2M  1 loop /snap/snapd/13269
loop7         7:7    0 57.4M  1 loop /snap/core20/1084
loop8         7:8    0   62M  1 loop /snap/lxd/21032
loop9         7:9    0 28.2M  1 loop /snap/snapd/13643
sda           8:0    1 30.6M  0 disk
mmcblk0     179:0    0 59.7G  0 disk
├─mmcblk0p1 179:1    0  256M  0 part /boot/firmware
└─mmcblk0p2 179:2    0 59.4G  0 part /

Note: mmcblk0 is another working SD card

When try to format it with widows OS.

windows

Raspberry pi 4 to measure temperature and humidity with DHT11/DHT22 sensor

pip3 install adafruit-circuitpython-dht
apt-get install libgpiod2

temp.py

import Adafruit_DHT
import time
 
DHT_SENSOR = Adafruit_DHT.DHT11
DHT_PIN = 4

#while loop is there because sometime it does not get the temp.
while True:
    humidity, temperature = Adafruit_DHT.read(DHT_SENSOR, DHT_PIN)
    if humidity is not None and temperature is not None:
        print("Temp={0:0.1f}C Humidity={1:0.1f}%".format(temperature, humidity))
    else:
        print("Sensor failure. Check wiring.");
    time.sleep(1);

run:

python3 temp.py

For DHT22 sensor:

temp-dht22.py

import Adafruit_DHT
import time

DHT_SENSOR = Adafruit_DHT.DHT22
DHT_PIN = 4

humidity, temperature = Adafruit_DHT.read(DHT_SENSOR, DHT_PIN)
if humidity is not None and temperature is not None:
    #print("Temp={0:0.1f}C Humidity={1:0.1f}%".format(temperature, humidity))
    print("{0},{1}".format(temperature, humidity))
  • shell script to send over pushgateway
root@lp-arm-1:~# cat /opt/cron/get_temp_dht22.sh
#!/bin/bash

t_and_h=$(python3 /opt/cron/get_temp_dht22.py)

temprerature=$(echo $t_and_h | awk -F ',' '{print $1}')
humidity=$(echo $t_and_h | awk -F ',' '{print $2}')
echo "room_temp $temprerature" | curl --data-binary @- http://192.168.0.183:30008/metrics/job/room_temp/instance/lp-arm-1
echo "room_humidity $humidity" | curl --data-binary @- http://192.168.0.183:30008/metrics/job/room_humidity/instance/lp-arm-1

raspberry pi 4 wifi setup using command line only – bash

  • find the wifi adaptor name
lshw

ls /sys/class/net

it was wlan0 in my case

  • edit /etc/netplan/50-cloud-init.yaml
network:
    ethernets:
        eth0:
            dhcp4: true
            optional: true
    version: 2
    wifis:
        wlan0:
            optional: true
            access-points:
                    "SSID-NAME":
                            password: "your_password"
            dhcp4: yes
  • Test the config
netplan try
netplan --debug try

This command will make the above changes for 120seconds if anything wrong it will be reverted back. OR you can hit Enter to make the changes.

  • apply config
netplan generate 
netplan apply
#enable wifi module

modprobe brcmfmac

#disable
modprobe -rv brcmfmac


nano /etc/modprobe.d/raspi-blacklist.conf

blacklist brcmfmac
blacklist brcmutil

More : https://raspberrypi.stackexchange.com/questions/108636/setting-wifi-up-via-the-command-line-ubuntu-server-18-04-4-lts-raspberry-pi-4

https://huobur.medium.com/how-to-setup-wifi-on-raspberry-pi-4-with-ubuntu-20-04-lts-64-bit-arm-server-ceb02303e49b

raspberry pi fan on/off automation based on cpu temp

Note : This does not work because IO pins does not enough power to run fan.

fan.py

import RPi.GPIO as GPIO
from time import sleep
import sys

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(8, GPIO.OUT, initial=GPIO.LOW) 

if sys.argv[1] == "on":
 GPIO.output(8, GPIO.HIGH)
 print("on")
else:
 GPIO.output(8, GPIO.LOW)
 print("off")

Dockerfile

FROM python:slim-buster
WORKDIR /fan
RUN apt update && \
    apt install python-rpi.gpio python3-rpi.gpio -y 
COPY fan.py .

Docker build

docker build -t fan .

Docker run command switch on

docker run -it --device /dev/gpiomem fan python2 fan.py on

Docker run command switch off

docker run -it --device /dev/gpiomem fan python2 fan.py off

fan.sh

#!/bin/bash

cpu=$(</sys/class/thermal/thermal_zone0/temp)

cpu_temp=$(echo "$cpu/1000" | /usr/bin/bc)
echo $cpu_temp

if(("cpu_temp" >= "65"))
then
echo "more 65 on fan"
docker run -it --device /dev/gpiomem fan python2 fan.py on
else
echo "less 65 off fan"
docker run -it --device /dev/gpiomem fan python2 fan.py off
fi

More: https://raspberrypihq.com/making-a-led-blink-using-the-raspberry-pi-and-python/

https://stackoverflow.com/questions/48441737/docker-error-no-access-to-dev-mem-try-running-as-root

raspberry pi as kubernetes worker node

  • Install docker
apt-get install \
    apt-transport-https \
    ca-certificates \
    curl \
    gnupg \
    lsb-release

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

echo \
  "deb [arch=arm64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
  $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

apt-get update

apt-get install docker-ce docker-ce-cli containerd.io

https://docs.docker.com/engine/install/ubuntu/

echo 'cgroup_memory=1' > /boot/cmdline.txt


echo '{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2"
}
' > /etc/docker/daemon.json



sudo sed -i '$ s/$/ cgroup_enable=cpuset cgroup_enable=memory cgroup_memory=1 swapaccount=1/' /boot/firmware/cmdline.txt


cat <<EOF | sudo tee /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

sudo sysctl --system
  • Install kubernetes component
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -

cat <<EOF | sudo tee /etc/apt/sources.list.d/kubernetes.list
deb https://apt.kubernetes.io/ kubernetes-xenial main
EOF

apt update && sudo apt install -y kubelet kubeadm kubectl


echo '[Service]
Environment="KUBELET_KUBECONFIG_ARGS=--bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf --cgroup-driver=systemd"
Environment="KUBELET_CONFIG_ARGS=--config=/var/lib/kubelet/config.yaml"
# This is a file that "kubeadm init" and "kubeadm join" generates at runtime, populating the KUBELET_KUBEADM_ARGS variable dynamically
EnvironmentFile=-/var/lib/kubelet/kubeadm-flags.env
# This is a file that the user can use for overrides of the kubelet args as a last resort. Preferably, the user should use
# the .NodeRegistration.KubeletExtraArgs object in the configuration files instead. KUBELET_EXTRA_ARGS should be sourced from this file.
EnvironmentFile=-/etc/default/kubelet
ExecStart=
ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS' > /etc/systemd/system/kubelet.service.d/10-kubeadm.conf


systemctl daemon-reload

systemctl restart kubelet

https://opensource.com/article/20/6/kubernetes-raspberry-pi

https://stackoverflow.com/questions/45708175/kubelet-failed-with-kubelet-cgroup-driver-cgroupfs-is-different-from-docker-c