"In het verleden behaalde resultaten bieden geen garanties voor de toekomst"
As you might know, I like to understand how things work. This applies very much to physical, technical things, but also to laws and regulations, and then in particular my income tax. After the year ends, the Belastingdienst software can calculate your taxes for you, but I would like to be able to understand and predict that calculation. Especially since I started as a self-employed contractor, it…
For a project (building a low-power LoRaWAN gateway to be solar powered) I am looking at simple and low-power linux boards. One board that I came across is the Milk-V Duo, which looks very promising. I have been playing around with it for just a few hours, and I like the board (and its SoC) very much already - for its size, price and open approach to documentation. The board itself is a small…
On my server, I use LVM for managing partitions. I have one big "data" partition that is stored on an HDD, but for a bit more speed, I have an LVM cache volume linked to it, so commonly used data is cached on an SSD for faster read access. Today, I wanted to resize the data volume: # lvresize -L 300G tika/data Unable to resize logical volumes of cache type. Bummer. Googling for the error message…
A few months ago, I put up an old Atom-powered Supermicro server (SYS-5015A-PHF) again, to serve at De War to collect and display various sensor and energy data about our building. The server turned out to have an annoying habit: every now and then it would start beeping (one continuous annoying beep), that would continue until the machine was rebooted. It happened sporadically, but kept coming…
When sorting out some stuff today I came across an "Ecobutton". When you attach it through USB to your computer and press the button, your computer goes to sleep (at least that is the intention). The idea is that it makes things more sustainable because you can more easily put your computer to sleep when you walk away from it. As this tweakers poster (Dutch) eloquently argues, having more plastic…
After I recently ordered a new laptop , I have been looking for a USB-C-connected dock to be used with my new laptop. This turned out to be quite complex, given there are really a lot of different bits of technology that can be involved, with various (continuously changing, yes I'm looking at you, USB!) marketing names to further confuse things. As I'm prone to do, rather than just picking…
For a while, I've been considering replacing Grubby, my trusty workhorse laptop, a Thinkpad X201 that I've been using for the past 11 years. These thinkpads are known to last, and indeed mine still worked nicely, but over the years lost Bluetooth functionality, speaker output, one of its USB ports (I literally lost part of the connector), some small bits of the casing (dropped something heavy on…
Recently, I've been working with STM32 chips for a few different projects and customers. These chips are quite flexible in their pin assignments, usually most peripherals (i.e. an SPI or UART block) can be mapped onto two or often even more pins. This gives great flexibility (both during board design for single-purpose boards and later for a more general purpose board), but also makes it harder to…
For this blog, I wanted to include some nicely-formatted formulas. An easy way to do so, is to use MathJax, a javascript-based math processor where you can write formulas using (among others) the often-used Tex math syntax. However, I use Markdown to write my blogposts and including formulas directly in the text can be problematic because Markdown might interpret part of my math expressions as…
Or: Forcing Linux to use the USB HID driver for a non-standards-compliant USB keyboard. For an interactive art installation by the Spullenmannen , a friend asked me to have a look at an old paint mixing terminal that he wanted to use. The terminal is essentially a small computer, in a nice industrial-looking sealed casing, with a (touch?) screen, keyboard and touchpad. It was by "Lacour" and I…