Pi Learning Experience

In the past I had used a 35mm camera for several years and accumulated a lot of photographs. Some have been scanned and migrated onto digital media but there are several boxes and albums still remaining to be processed. The scanner I have is an ancient Epson machine which connects perfectly via USB to the Pi 5 and just works. My software for scanning everything is XSANE. Once the scanner is powered on and recognised, I select the page size, either A3 portrait or A3 landscape, hit the Acquire preview button to get a preview which is displayed in a preview window. Usually I  select the area to scan and zoom into that and preview again to check it is right. Once satisfied with the results I hit the Scan button for a full colour scan. The default settings are a full colour scan at 300px/in for a normal sized print. The file options are amended to ensure I am saving into the working directory. File numbering is incremented automatically. Once scanned, Gimp handles processing. I have ins...

I recently bought some pre-loved CDs (mainly blues with John Lee Hooker, Ella Fitzgerald, Fats Domino) and wanted to transfer them to an old Android phone which I use as a music player. I use VLC for Android as a player, have uninstalled the other apps off the phone and there is no SIM loaded because Wi-Fi is either from the house or off my main phone as a Hot-Spot.. I previously used GRip a long time ago but it seems to be defunct now with not much apparent support (though there is a new maintainer, so there will probably be new updates soon). My search revealed 2 apps in which I was interested. "abcde" which is described a "A Better  CD Extractor" and "fre:ac". abcde is a command line tool and the progress status is delivered as text to the screen. fre:ac is a GUI based application with all progress status shown graphically in the GUI. I tried both and went with fre:ac because by default the CD information was retrieved more accurately. I would have pref...

  It is frustrating when a process you expect to work all the time only works intermittently. Using ssh to login into a headless device should be deterministic. The device has ssh enabled and the sshd server enabled and running, the Avahi server for mDNS is also running so you expect that ssh into <host>.local will work. Unfortunately sometimes it does not. In my repository of Raspberry Pi hardware, I have a Pi Zero 2W which is a training ground for learning about flask. It was setup using the usual methods documented by Raspberry Pi. At times the Zero would not let me login via ssh. The board was powered up with a standard Pi USB power supply and usually I could just ssh in. However there were many instances where ssh would result in an "Unknown host error" message or "Could not resolve error" message.  After fixing the ssh problems with the Pi 5 earlier, I decided to investigate whether the same fix is applicable to the Zero 2W. Research indicated that the Z...

I had an issue where attempting to ssh login into the Pi 5 using <hostname>.local did not work. The " .local " domain means that the internal LAN IP address for the device does not need to be remembered because the system finds, advertises it on the internal network and all other hosts record it. The displayed message: ssh: Could not resolve hostname <hostname>.local. Name or service not known. was a clue, albeit an obtuse one. I checked the Pi logs with journalctl and reviewed dmesg and systemctl status but nothing obvious was evident. Nothing showed up.  Internet search indicated that maybe the mDns config was not quite right., specifically the DNSMulticast option in resolved.conf. i.e the .local name could not be resolved, perhaps because it was not registered. To fix this (one of the fixes according to my friends on the WWW is that the DNSMulticast option setting in the /etc/systemd/resolved.conf file is not set correctly. Invoke your preferred editor: sudo...

My Pi 5 running Ubuntu Server was failing to start a docker service. I had originally installed docker before moving to LXD/LXC. I only spotted the docker failures after checking the logs when I was trying to understand why the Pi was suspending itself overnight. I began by removing the daemon.json file in /etc/docker by  renaming it to daemon.json.old. I started to look for failures using journalctl to search for any failures related to docker: journalctl | grep docker and found a whole bunch of messages indicating that the docker service failed to start. You can also use systemctl to check for failing services using: systemctl list-units --type service --state running,failed To remove docker use: sudo apt remove docker-ce Then restart the  Pi sudo reboot Finally recheck the logs using journalctl: journalctl | grep "Feb 14" | grep docker    Feb 14 11:06:52 systemd[1]: docker.service: Failed with result 'exit-code'. Feb 14 11:06:52 systemd[1]: Failed to start docker...

The Base Duo sat around for a couple of days whilst I completed some other housekeeping on my laptop. Finally, I looked up the installation instructions on the Pimoroni site. That's the reference but I put together a summary below mainly for myself but you are welcome to using it as a precursor. I followed the install instructions pretty much except I installed Ubuntu Server (which then meant I lost access to the Pi via rpi-connect. However ssh works fine after the service is enabled. In short: Unpack Base Duo and check all parts are present. I had some spare screws in the package. Install 4 of the larger spacers on the Base Duo board. Use either the very long screws or the medium screws. The long screws are used if you want to add a hat to the top of the Pi. Install the Pcie connection cable on the board so the labelling is facing away frm the board. The connector is a bit fiddly to lift but a tiny screwdriver helps. Push the top down to capture the cable. Flip the board and inser...