Tech on Sarah's Microblog

Tue, 22 Sep 2026 23:28:29 +0200

Found a tiny table clamp. It works well and looks super clean.

Also I’m pivoting. Literally. I realized the whole point of my workdesk monitor is being able to pivot it in front and to the side. That’s not gonna work with a bunch of cables anchored to the desk. Now how to mount this beneath the monitor safely… I first considered mounting to some plastic tabs on the back, but i worry that would make for too weak a structure… Maybe shim the vesa mount?

Sun, 20 Sep 2026 01:56:15 +0200

It ingests through a directory in the application data… On the nvme disk.

Fri, 18 Sep 2026 20:07:34 +0200

Oh I could of course just have done

vidid=$(grep 'comment=' meta.txt | tr -d '\n' | tail -c 11)

instead… Which would also avoid getting a false video ID from a link in the description. Ask me how I know.

Fri, 18 Sep 2026 02:17:16 +0200

I’ve been backing up youtube videos from a select few channels for reasons for quite a while now, though I never got around making them actually easy to watch. It feels very silly to have the files available locally and still stream them from an unreliable service. So I’m gonna give Tube Archivist a try.

I of course don’t want to redownload everything, but in my infinite wisdom, I decided to remove the youtube video IDs from the file names, which is like the one thing you need for importing existing files. But at least I have the original URL saved in the file metadata so, if you’re in the same situation, you could do something similar to this using ffmpeg:

Wed, 16 Sep 2026 23:59:07 +0200

Found a bunch of smaller harddisks in the trash a while back. A recent (enjoyably accessible) L1Techs video on hdd diagnostics and recovery reminded me I should probably see if I could find some place to get them back into service.

https://forum.level1techs.com/t/mechanical-drive-bad-sectors-the-drive-is-not-always-dead-a-primer/255113

My usually disk ripping machine is taking the duty of hdd tester. I have motherboards with enough sata sockets to process everything at once, but I just want it running as a background activity that requires minimal thinking or memory on my end.

Fri, 11 Sep 2026 22:01:46 +0200

Yea something like that. Need a clamp to keep it in place though.

Working on little patch panels for my work desks

Thu, 10 Sep 2026 22:04:44 +0200

The idea is to minimize any cable clutter on the desks while making it easier to set up a device or tool. So if I need to use a scanner, I can pull it from its drawer where it’s packed with a power and usb cable, and just plug it in.

Sat, 05 Sep 2026 23:04:51 +0200

Some future confusion avoided…
Got a USB cable tester just out of curiosity. I found:

Three actually bad cables. Two mini and one micro USB. One had clear rust marks. One had limited insertion depth. One showed no signs at all.
A bunch of mini USB and some micro USB cables don’t have the shield connected. Perhaps optional in the spec?
Mac USB-C cables have strange behavior of apparently tying the CC pins to ground/shield at one end? Either that or perhaps they have some internal electronics going on.

Mon, 31 Aug 2026 23:40:49 +0200

I immediately mess up my first attempted embroidery pattern.

Download

I had just forgotten to tighten the screw for the needle. Didn’t even break. Though I had to scrap the job.

How hard could it be?

Mon, 31 Aug 2026 23:29:11 +0200

…

Got absolutely sniped today

Wed, 26 Aug 2026 23:00:02 +0200

I was asked so how does this thing work?

From papanek.org via smjny.com

This is the ‘Tin Can Radio’ by Victor Papanek and George Seeger. There appears to exist exactly three images of this thing online. It’s a radio reciever from 1962 intended for ’third world’ countries. From texts referencing it, it’s generally explained that the radio is not selective (it can not be tuned), that it is somehow powered by burning candle wax or cow dung in the tin can, it features a transitor (?), a 9 cent bill of materials and is possible to assemble by hand.

Sat, 22 Aug 2026 19:27:28 +0200

So anyways I started ~~blasting~~ redesigning.

Sat, 22 Aug 2026 19:03:10 +0200

Complete RE of the original Frekvens controller and LED matrix board.

Wed, 19 Aug 2026 18:01:38 +0200

The MCU on the controllerboard has the markings 89F112 000, which appears to be the CMS89F112 from Cmsemicon. It’s listed on jlc, for an estimated unit price of 0.3 USD. Hard to beat. The datasheet is in chineese, but looks to have

A 2K x 14 bit flash memory (I’m unfamiliar with the practicality of 14 bit memory?).
144 bytes of RAM.
Inbuilt ADC, comparators, timers, PWM outputs, buzzer driver and a sleep mode.
A voltage range of 1.8-5.5V (at 4MHz, or from 2.5V at 8MHz).

A very capable little device. 144 bytes of RAM is not a lot, a bitfield for the LED matrix would take up 32 bytes, almost a quarter of memory. Still, that is absolutely enough for more complex or interesting effects on the matrix, like iterative or dynamic animations. My claim still stands: TE’s embedded developers dropped the ball on this one.

Tue, 18 Aug 2026 23:49:39 +0200

Scans and sketch of the original circuit:

Cleaner sketch to follow…

Ikea Frekvens LED matrix modding

Mon, 17 Aug 2026 23:22:47 +0200

I found a couple of ikea frekvens LED matrix cubes from that teenage engineering collab in a thrift store in Vienna. They were cheap and I’d heard about people modding them. Plugged in, they provide possibly the most dissapointing lightshow I’ve seen:

The LED matrix cubes 'dancing' to sounds.

Download

Whatever electronics they’ve got in there, it’s doing a very simple job: Show a static frame of a pre-baked five frame looping animation. Monitor a microphone and progress the animation each time a loud sound occurs. Check two buttons on the back to turn the LEDs on or off, and switch between a few different animation sets.
That’s it. Nothing dynamic, nothing exciting. Why not make it just a bit more exciting?

Tue, 11 Aug 2026 21:34:22 +0200

Soldering a v1.1 board of the flying checklist project. Blaming my tools in the solder paste being way out of date and unrefrigerated. Reflow went surprisingly well though. No tombstones, one bridge, a few unconnected pads.

Sun, 09 Aug 2026 22:32:47 +0200

Found a 60x60 LED panel for 20dkk in the thrift store last week. Found an LED driver in the trash a couple days later. Just had to adjust the output power and change the power connector. Who knows, dali control might be broken, but I’m not living in an office. Think it’s gonna be my new work desk light.

Tue, 04 Aug 2026 22:55:31 +0200

Bought a couple of the AKY0477 batteries from TME and got them installed. There’s a bit of free space around the camera lens where extra cable can be tucked in.

Batteries replaced aaand.. it works perfectly.

Now what in the world can I use a little action cam for…? I also found the cage for it with a broken hinge. Maybe worth fixing.

Rollei Bullet HD actioncam with dead batteries

Tue, 04 Aug 2026 00:00:23 +0200

I found a Rollei action camera in the trash. Seems fully functional except it won’t take a charge. The shell clicks open after removing the four visible screws at each side of the camera. The camera has two lipo flat-packs wired in parallel and soldered to the board. Only one of the cells has a protection circuit, the other’s wired in behind it. Both cells have swollen significantly.