References https://www.freecodecamp.org/news/build-your-own-wireguard-vpn-in-five-minutes/ https://bootstrap-it.com/wireguard-vpn/ https://www.smarthomebeginner.com/linux-wireguard-vpn-server-setup/ https://www.procustodibus.com/blog/2021/03/wireguard-logs/ https://www.procustodibus.com/blog/2021/01/wireguard-endpoints-and-ip-addresses/ https://www.procustodibus.com/blog/2022/06/multi-hop-wireguard/#internet-gateway-as-a-spoke

I had some issues with my heating. Also an technition had no luck. The path forward was unclear.. I am not a technition for heatings, I am an IT guys. So what is obvious? To monitor the “performance” of my heating in order to track the issue and try to fix it. What I can say it was a full success. I would call the solution with my heating a patch and it is clear that I need a new one.

This article is not about the problem of my heating as itself it a about a idea. I want to collect data from our house like heating, solar, power consumption, etc. For the heating I already have a use case for the parts right now not.

But how does my current solution for the monitoring of my heating look like. ESP32 –> MQTT Broker <– App

Issue: the Raspberry Pi (RPi) has crashed and the boot process ends up into a kernel panic. The reason is unclear. I am connecting the serial output from the RPi to a FTDI to see the issue on the screen. Which kind of FTDI or USB-to-serial board you are using is not important. A cheap model is fine. You must connect the FTDI pins to the RPi pins this way

Please refer to this resources for more information how to connect the serial output from the RPi:

• https://unix.stackexchange.com/questions/208260/how-to-scroll-up-after-a-kernel-panic
• https://unix.stackexchange.com/questions/307390/what-is-the-difference-between-ttys0-ttyusb0-and-ttyama0-in-linux/367882#367882
• https://learn.adafruit.com/adafruit-ft232h-breakout/serial-uart
• https://sites.google.com/site/cartwrightraspberrypiprojects/home/steps/macbook-usb-to-raspberry-pi-using-ftdi
• https://makezine.com/article/technology/raspberry-pi/talking-to-the-raspberry-pis-serial-console-with-an-ftdi-breakout-board/

Configure the RPi boot using the cmdline.txt file. My example:

console=serial0,115200 console=tty1 earlycon=pl011,mmio32,0x3f201000 root=PARTUUID=6c586e13-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait

Add this to the /boot/config.txt in order to disable the mini UART and enable the real UART

dtoverlay=disable-bt

Please refer to this resources for more information how to configure the RPi for a serial output:

• https://www.abelectronics.co.uk/kb/article/1035/serial-port-setup-in-raspberry-pi-os

Boot the RPi.

Open the serial line using minicom. Tools like screen works as well

minicom -b 115200 -D /dev/ttyUSB0

You should see the boot output. I got a random kernel panic. So that I decided to rescue the data on my sdcard.

dd if=/dev/sde of=sde-card-copy.img_new bs=4096 conv=notrunc,noerror status=progress

Another option is ddrescue, especially if your disk is damaged

ddrescue -n -r 3 /dev/sdc sdc-card-copy.img_ddrescue2 mapfile2

Please refer to this resources for more information about a disk backup using dd:

• https://askubuntu.com/questions/227924/sd-card-cloning-using-the-dd-command
• https://superuser.com/questions/622541/what-does-dd-conv-sync-noerror-do
• https://datarecovery.com/rd/how-to-clone-hard-disks-with-ddrescue/
• https://www.linux.com/topic/desktop/gnu-ddrescue-best-damaged-drive-rescue/
• https://www.technibble.com/guide-using-ddrescue-recover-data/

Mounting the device

• https://unix.stackexchange.com/questions/316401/how-to-mount-a-disk-image-from-the-command-line

Found on StackOverflow. I have added an answer to it Link.

Found on StackOverflow. I have commented it.