January 14 2025 3D printers, Proxmox, Geograph. ash
David reported that ATC_MiThermometer cannot flash Xiaomi thermometers any longer even though the devices look exactly the same as the earlier ones but require soldering.
He had had to buy a new Raspberry Pi 3+ with heatsink after his existing one overheated while 3D printing a battery holder. He had got a second printer from Kriss and Shi which is 24V and so there is nothing to power a 12V fan!
There are loads of options for battery holders of different sizes; you just load the STL (stereolithography) file; they look like a beer crate, stack like a beer crate and take 5½ hours to print.
In answer to a later question from John, David explained that a 3D printer has an accelerometer on the 3D printer head to measure vibrations — Steve explained that, for 3D printing, the accelerometer calibrates x and y inertia. Klipper does automatic compensation. With OctoPrint you can only run one printer whereas Klipper can run two.
David noted that G-codes are very fine grained and it is not clear with Klipper what it is doing; with Marlin firmware the printer’s motherboard understands things better.
Steve noted that 3D printer motors are a lot quieter these days though the Voron is quite noisy.
Brian demonstrated his Proxmox server setup; while it can manage Linux Containers (LXC) and virtual machines, he had not been able to get the Home Assistant image to connect.
To create a VM or container within Proxmox, you need to provide a registration number over 100 for the node, a hostname and a password, select a template and a storage location and specify how much space it is to have, how many cores it can use, the size of the memory it can access and the network; IP addresses need to end in …/24 and you can use DHCP or DNS.
He showed the list of instances he had created and how you could view their specs and statistics and summarised the options for operating them. He mentioned that you can create a clone of an instance, for example, for experimenting.
Steve drew attention to the Proxmox VE Helper-Scripts which work with LXC containers or a VM and also the snapshot option. He also mentioned that, if you have two Proxmox hosts, you can create a cluster and then migrate from one host to the other; the migrate option only appears when you have set up a cluster. For example, you cannot upgrade from version 7 to version 8; so you have to have each version on a separate host within a cluster and then migrate instances from one to the other. Proxmox updates all the time.
Brian asked what he was running to keep track of who is leaving and arriving and where he got the Windows VM from and about tailscale.
Steve explained that his servers were named Eta and Theta and, when he wanted to migrate things, he had to go to Data Center which is where you manage a cluster, say where you want to move an instance and it then gives you a key to paste into the instance. You can clone a Windows instance on GitHub to register Windows; the ones with a blue dot are created with scripts.
Brian asked about general backups; Steve runs scripts to do Cron jobs: one to back up Linux once a week and one to back up Windows once a month; Steve has written rsnapshot to run in the command line.
Brian had found that you can use the command line to install a desktop environment on Proxmox — Xfce works. He had also installed different profiles with Firefox Multi-account Containers to view different stations all over the world, noting that NordVPN will automatically set the time of the country which is useful when websites use the local time to verify a link. Steve noted that, while Private Internet Access is cheaper than NordVPN, it is not as good and Brian mentioned that Proton VPN doesn’t have a Linux option.
Brian went on to mention that he uses a standard SSD for NextCloud and rsnapshot for daily backups; he has also set up a CA to make his own authorised certificates for NextCloud. He also noted that, when using IP, you have to get the order of the commands right.
Bernie introduced the Geograph Project which aims to collect geographically representative photographs and information for every square kilometre of Great Britain and Ireland. It had been started by some guys in Aberystwyth and allows you to upload photographs of the UK by location. The Ordnance Survey sponsor the project rather than doing it themselves.
David mentioned that, when they started, they had used hectad for 100 monads, the grid squares into which the country is divided, and had a poll for the right name for 100 hectads — some southern contributors wanted ‘hundred’ for which the northern equivalent had been ‘wapentake’ — David suggested ‘myriad’ which was adopted.
David also bemoaned the fact that, though it operates under a Creative Commons licence, not all users respect that.
In response to a question about a call to the Almquist or ash shell, it was noted that inserting #!/bin/bash will cause the script to default to bash and that ash was ported to Debian as dash (Debian Almquist shell).