Marcus Folkesson

Embedded Linux Artist

What time is it? RTCs explained in embedded Linux

What time is it? RTCs explained in embedded Linux Most smart devices keep track of time and it's usually something that everyone expects to be "right", accurate and just work. I mean, you can keep time pretty well with just a pendulum or a spring [1], so why would this be a complicated thing in an embedded system? Your smart alarm clock, smart phone or even your new cool IoT refrigerator make all use of the time for sure, but they probably do it for different purposes and have different requirements of the accuracy of time.

cover

Posted by Marcus Folkesson on Tuesday, July 2, 2024

Knife making

Knife Making It's been a long time since I made knives. Knife making was actually the reason I bought my gas forge a few years ago and it's still something I intend to do. I forged a few knife blades back then, but it was way too much manual grinding to be fun and I didn't have the right tools back then, and I'm still missing a belt grinder in my toolbox.

cover

Posted by Marcus Folkesson on Monday, July 1, 2024

NOAA Weather satellites

NOAA Weather satellites Me and a friend started to talk about SDR (Software Defined Radio) and GNURadio [1], which reminds me of a old project I did for many years ago - reading out images from NOAA weather satellites using SDR, a QFH antenna and GNU Radio! I found some old pictures, but unfortunately, I do not remember the details as it was almost ten years ago. But I do know that we were using a HackRF [3] to catch the radio signals.

cover

Posted by Marcus Folkesson on Thursday, May 30, 2024

Lund Linux Conference 2024

Lund Linux Conference 2024 I have started to write a few lines about this conference each year as I think it deserves attention. Also, the more attendees we are, the more fun we get. The conference Lund Linux Conference (LLC) [1] is a "half-open" conference located in Lund. It's a conference with a high quality and I appreciate that the athmosphere is more familiar than at the larger conferences. I've been at the conference several of times before and the quality on the talks this year was as good as usual.

cover

Posted by Marcus Folkesson on Tuesday, May 28, 2024

TIL - Magic SysRq with SystemD

TIL - Magic SysRq with SystemD TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post The Magic SysRq [1] is a ueful tool for debugging and recovering from a frozen system and is something I use frequently. SystemD sets the permissions bitmask to 0x10 by default [2] , it means that only a subset of the available features is allowed.

cover

Posted by Marcus Folkesson on Sunday, May 19, 2024

Versioning with SWUpdate

Versioning with SWUpdate TLDR; It is now possible to let SWUpdate manage the sw-versions file entirely thanks to the --gen--swversions feature I've been working on. SWUpdate SWUpdate [1] is a project I've been using for a very long time for updating firmware on embedded systems. The update service is a critical part of any embedded system, so having a well-tested, flexible, competent and ready-to-use solution is so much worth. Too many times I've seen custom made update services that contain bugs, is not flexible enough or using slots for whatever software that could be updated.

cover

Posted by Marcus Folkesson on Wednesday, May 15, 2024

Flattened Image Tree (FIT) with Yocto

Flattened Image Tree (FIT) with Yocto Long time ago, I wrota a post [1] that compared the legacy Image format against Flattened Image Tree Format (FIT) [2] and highlighted the benefits of using it. The benefits is still valid and FIT images is my preferred way to boot a Linux kernel. Dispite that, I almost never see that FIT images is used in examples nor Board Support Packages (BSPs).

cover

Posted by Marcus Folkesson on Tuesday, May 14, 2024

Building an owl house

Building an owl house I like owls. I always have. There are so many reasons to be fascinated about owls. For example, did you know that Owls has special flight feathers that makes them almost silent? That they can swivel their heads around (how cool is'nt that?) is commonly known, but that they can do the same with their toes too? Their eares are asymmetrical to make them better to pinpoint the location of sounds in multiple dimensions?

cover

Posted by Marcus Folkesson on Monday, May 13, 2024

Repair of an IC-211E HAM Radio

Repair of an IC-211E HAM Radio A friend of mine (SM7FWZ [3] ) gave me an ICOM IC-211E, a 2M all mode transceiver that I'm having a lot of fun with. When I got it, it had one drawback - transmitting on SSB (Single Side Band) didn't work very well, neither for USB (Upper Side Band) nor LSB (Lower Side Band). The signal that reached the antenna was really disturbed, so here is something that needs to be fixed!

cover

Posted by Marcus Folkesson on Tuesday, May 7, 2024

Bird counting

Bird counting I've been counting birds for couple of years now, but for the last past six mounths I have also recorded which species I see at bird table. I live in the middle of a bird sanctuary, so I think it could be good to know my neighbors. So the main reason for this was to learn to tell the difference between different species for birds. I must say that this was a success, I can name about 30 different bird species with a fairly high degree of certainty around my bird table.

cover

Posted by Marcus Folkesson on Tuesday, April 16, 2024