planet – rojtberg.net

Logitech M720 Triathlon mouse – long-term review

In this post I want to take a look at the Logitech M720 mouse after having used it for 2.5 years.

Specs and durability

The specs are pretty common for a mouse you get today, so lets start with the special features:

There are side buttons, which I find pretty handy for navigating front/ back in the browser or a file manager
It can be paired with up to 3 devices at the same time, which makes it easy to use with your PC, Laptop and Tablet
It supports both Bluetooth LE and the Logitech Wireless Receiver
It is powered by a single, replaceable AA battery

Especially the last two points make this seem to be future-proof product that you can use for a long time.

Logitech is currently replacing their Wireless Receiver dongles by Logitech Bolt, so in the near future the Wireless Receivers will go away. But thanks to the Bluetooth support you will still be able to use the mouse without having to occupy a USB port just for using it.

Then, using standard AA batteries means that you just use some nice rechargeable ones. This means that you will never have to wait for the mouse to charge and that the mouse can out-live the battery. As you are probably aware from using your phone, rechargeable batteries wear-out over time until the device cannot be properly used any more.

So we finally got a mouse for the years to come? Well..

Built-in obsolescence

Unfortunately, Logitech made some design decision that drastically shorten the life-span of the device, even though they must have known better.

Rubber coating

The most obvious one is likely the rubber coating of the mouse.

Note how the plastic buttons look still perfectly fine in comparison

I took the images for this post after cleaning the mouse. So the dirt you see there is not the skin from my greasy hands, but rather said rubber coating disintegrating.
This is caused by your sweat which is slightly acidic and thus takes hold of the rubber.
There is a reason that Gamepads do not have such coating, even though having good grip is even more important there.
Also, the way the coating is used here, all it does is making the mouse look greasy after some time.

Bad switches

The less obvious issue are the used switches i.e. the things that perform the clicks.
Did you ever notice that after some time your mouse does incorrect double clicks or releases the click while drag and dropping on its own? Well, that means the switch starts wearing out.

The mouse uses OMRON D2FC-F-7N micro-switches in a cheap variant that is only rated for 10 million clicks (10M). While this sounds a lot, it yields to 6850 clicks/ per day for 4 years, which is not all that much if you think about playing a shooter or using photoshop.
The crazy part is that going for the 20M rated variant (2x the durability) only costs 50 ct more (pack of 5 on amazon). This would make the mouse merely 1€ more expensive – probably way less even as Logitech can negotiate bulk discounts on these things.
Given that the mouse is priced at 50€, I do not think we can pass this off as cost optimization.

Note, that even more expensive Logitech Mice, like the MX Master have the rubber coating issue and use the same cheap 10M rated switches.

Introducing ODRS Browser

GNOME Open Desktop Ratings is the service that enables user ratings in various Linux app stores like the Snap-Store, Gnome Software and KDE Discover.

While it nowadays works for users by providing a mostly useful star rating, from a application developer perspective the story is very grim.

Basically one only gets the users view, which provides an average rating and some reviews in the current locale.
This means you might see something like “2 Stars from 80 Reviews” – but the 3 reviews in your current locale are all 4-5 Star.
To see something else you have to change the locale and restart the app store – which is inconvenient and confusing.
As a developer, seeing the negative reviews is crucial, as people often just post bug reports there and this is the only way to find out why the app did not work for them.

Therefore I quickly hacked together a web-based browser for the ODRS service, skillfully named

ODRS Browser

This allows accessing the ODRS service from the web and shows the reviews from multiple locales at once. The idea here is that often people write reviews in english – regardless of their current locale. Currently, ODRS has no logic to detect that.

Also, if your app is packaged in different formats like snap and flatpack and deb, you can see the reviews of all variants in the overview.

Unfortunately, ODRS currently does not set the CORS header which prevents browsers from accessing it directly. The data that you see right now was scraped with python script. But once this issue is fixed, the ODRS Browser will be able to use live data.

Debugging Python with GDB on Ubuntu

Lets say you want to debug a python process that is either already running or crashing in native code. Pythons PDB is of no help here and you will have to use low-level GDB debugger. Fortunately, it comes with support for debugging high level python scripts.

However, while the actual python-gdb commands are nicely described here, that page lacks important details on how to get python-gdb in the first place. We are merely told that a python-gdb.py is needed.

On Ubuntu/ Debian, this file is included in the python3-dbg package:

sudo apt install python3.10-dbg

Installing that is sufficient, if you use the matching python3 package. You can go ahead and connect to some running python process via:

gdb -p <PID>
# verify that the script is loaded
(gdb) info auto-load
# get a python backtrace
(gdb) py-bt
Traceback (most recent call first):
  File "/usr/lib/python3.10/selectors.py", line 416, in select
    fd_event_list = self._selector.poll(timeout)
  File "/usr/lib/python3.10/socketserver.py", line 232, in serve_forever
...

In case Ubuntu is merely a host and you use coda, you can still use the host python-gdb.py – even if the python versions dont match. You will have to load the script manually though like:

(gdb) source /usr/share/gdb/auto-load/usr/bin/python3.10-gdb.py

Fix Steam Deck Input in Desktop Mode

While older SteamOS releases used to map the right trigger to the left mouse button by default, in current SteamOS you can only click by using the touchpad. However due to the way you hold the device it is really fiddly – especially if you try to drag and drop something.

Fortunately, there is a way to fix this via a setting in Steam. For this you need launch Steam when in Desktop Mode. There, switch to big picture mode and go to

Settings > Base configuration > Desktop Configuratiom

In this view you can configure the inputs to your liking

I suggest you to go with the following setup

Right trigger for left click (sounds counter-intuitive, but works well)
Left trigger for right click
Left touchpad for moving the mouse (doh)
Right touchpad for scroll wheel

With this configuration you can use the desktop mostly pain-free.

Using Docker with SLURM

The SLURM documentation provides you with the basic information that you can use Docker withing SLURM – as long as you use rootless Docker. However some crucial pieces are missing.

The issue that you will immediately run into is that the SLURM resource allocation is not propagated to docker at all. E.g. if you start your job with srun --gpus 1 docker ... all GPUs will be available to docker nevertheless.

The issue here is that Docker uses a manager daemon that the docker CLI communicates with. And that daemon does not know anything about SLURM or any resources it allocated for the job.

The solution is to start a daemon per job (instead of per user) as one user might want to run different jobs with different allocations on the same machine. The docker documentation gives you an idea on how to do that.

You will need to set at least the following parameters to make the daemon fully job-specific

# dockerd-rootless.sh requires XDG_RUNTIME_DIR
XDG_RUNTIME_DIR=/somewhere/including/$SLURM_JOB_ID
# export, so docker client sees it later on
export DOCKER_HOST=unix://$XDG_RUNTIME_DIR/docker.sock
dockerd-rootless.sh --host=$DOCKER_HOST --data-root=... --exec-root=...

Here, exporting DOCKER_HOST makes the docker CLI use the correct daemon.

The drawback of this method is that each job needs to pull the container again due to the separate data-root paths. Switching to podman might solve that.

Steam Deck SSD Upgrade

If you, like me, went with the entry level Steam Deck option with only 64 GB of internal storage, you likely realized quite soon that some games wont fit on it.

One option is to use the microSD expansion card slot. For current-gen games the throughput of only about 150 MB/s does not seem to degrade loading performance compared to a NVMe SSD.
However, given that the internal storage is upgradable, the only logical choice for keeping your PC master race status is to cram in the fastest NVME SSD inside that thing.

Specifically, you will need a one-sided SSD in the M.2 2230 for factor so it fits the space inside the Steam Deck.
I went with the KIOXIA Client-SSD BG5 512GB. Kioxia is the Toshiba spin-off for SSD drives, if you wonder about the brand. Although it is a PCIe 4.0 drive, its peak read throughput of 3.5 GB/s is within the practical limits of PCIe 3.0 of the Steam Deck.
Also, the active power consumption of 4.1W is quite close to the 3.8W drawn by the custom PHISON PS5013 E13 SSD that Valve uses.

You can follow the iFixit Guide for the steps to actually swap the SSD. Make sure to transfer the ESD shielding wrap to the new SSD.

To get Steam OS on the new drive, follow the official recovery instructions and select the “Re-image Steam Deck” script.
This will install Steam OS on the blank SSD – similar to how you would install Ubuntu from a live USB.

Benchmarking results

Next, I wanted to actually compare the speed of the upgraded NVMe SSD with the one of the stock eMMC memory. To this end I used KDiskMark – an open-source alternative to CrystalDiskMark that runs on Linux natively.

The tests were performed on SteamOS 3.3.1 using KDiskMark 2.3.0.

In short, the NVME offers roughly one order of magnitude faster throughput over the eMMC.
Whether you feel this in-game, highly depends on the given game. For older titles, even the eMMC is so fast, that you cannot read the hints on the loading-screen. However, for something like the Flight Simulator 2020 that shuffles huge assets around, it will surely be noticeable.

Finally, the peak read performance of 3.5GB/s is not reached. This might be due to the PCIe 3.0 bottleneck – I did not bother putting the drive in a PCIe 4.0 device. Still, there is a significant advantage in writing performance over the older Kioxia BG4 series, that only do 1.4 GB/s.

Computing replaygain for your Music library

TLDR; command at the end of post

If you want a equal loudness for your Music library the go to solution and the de-facto standard is ReplayGain.
If you are using a music streaming service, the provider is typically taking care of that for you – but maybe you want to migrate towards your own streaming solution.

ReplayGain analyses your audio files and stores their deviation from the baseline loudness as a tag. A compatible audio player can then read the tag and correct the playback volume so all you tracks have the same loudness.

Of course things get messy once you look at details like what the baseline loudness should be and how to determine loudness in the first place. Therefore we set the baseline once and for all as 89db and consider even tracks of the same album individually. If you disagree, feel free to branch off reading up the details now.

The next issue is that ReplayGain was born in a time where mp3 was synonymous to digital music, hence the algorithm was first implemented as the mp3gain CLI tool. Nowadays you also need aacgain and vorbisgain to cover all your formats, which is cumbersome to automate.

The larger issue with ReplayGain is that it defines loudness of a track by its peak volume. While a sane choice in theory, in practice the music and advertising industries raced to increase the perceived loudness without raising the peak volume. As broadcasters also used peak volume normalization, one could blow your eardrum with that very special advertisement.
Therefore the EBU R 128 was proposed which at its core is RMS based, meaning it is considering the average volume of the track.

Remember that ReplayGain merely adds a correction value to the tracks? This allows us to compute that correction value based on the R128 algorithm for a better normalization, which is exactly what the <a href="https://github.com/desbma/r128gain">r128gain</a> tool does.
Being written in modern day, r128gain also processes all possible audio files by hooking into ffmpeg as a filter.

So, without further ado, this is the command to normalize your Music library:

# pip3 install r128gain
r128gain -p -r Music/

This will preserve "-p" the file timestamps and recursively "-r" process all files in the given directory.

Trouble shooting

Note that if you previously used mp3gain, your files might contain non-standard lower-case replaygain_* tags, while r128gain will only write REPLAYGAIN_* tags.
To avoid confusing players with different values, you should remove the non-standard tags. This can be automated with eyeD3

eyeD3 -Q --remove-frame RGAD --preserve-file-times --user-text-frame=replaygain_track_gain: --user-text-frame=replaygain_track_peak: --user-text-frame=replaygain_album_gain: --user-text-frame=replaygain_album_peak: Music/

Refer to its documentation for the meaning of the parameters. For RGAD see here.

Header Image: “volume” by christina rutz (CC-BY-2.0)

Breaking free of Google

This post will be for those of you that care about privacy – i.e. if you want that information about you is exclusively under your control.
In that context not only Google is to blame, but actually most of the cloud services we know and use today.

Still Google will serve us as a nice placeholder as it is the market-leader when it comes to providing free services in exchange for your user-profile that Google in turn uses to sell target advertising. Even if you are fine with that, Google is also infamous for killing services – which might hit the one you rely on eventually.

As the world is moving mobile-first, a prerequisite for replacing a service is that we can easily integrate the replacement with an Android device.
Some might wonder why I chose Android here, given that it is made by Google. See, the problem is not who makes a service/ device, but who controls it. And with Android the main leverage for Google is bundling its services. If you take them away, the device itself is fully under your control – in contrast to Apple/ iOS.

Now, that we set the stage, lets start with:

Nextcloud

At the heart of our efforts will be Nextcloud. This started as an open-source alternative to Dropbox/ Google Drive, but is nowadays grown into a platform for a plethora of different services.
The main selling-point is that you can just install Nextcloud on your own machine – ensuring that your data stays private. The software being Open-Source also means that it is not under control of a single corporation – in fact Nextcloud was forked from its predecessor Owncloud after a corporation tried to put the screws on its users.

Note, that if you are serious about this, you will need to invest around 500€ to get a machine for hosting that is decently fail-safe. If you rather want to be cheap, you can also just use a RaspberryPi to get away with less than half of that amount. For inspiration, you can take a look on the built I use or on the list of commercial nextcloud device providers.

Files & Photos

By using the Nextcloud Android App, you can directly replace Google Drive/ Dropbox as this is the core functionality of Nextcloud.

Additionally, the App allows you to automatically back-up your Photos/ Videos and free the local storage so you can stop using Google Photos too.

Contacts & Calendar

Nextcloud also supports Contacts and Calendar out of the box. To integrate them with into your Android Device there is the DAVx5 app. This app will function as an additional data provider, so you can just continue using the stock Google Contacts and Calendar apps. Those will, however, stop sending any data to Google.

This is especially useful, if you run a small-business and must ensure that your customer data is private according to the CCPA/ GDPR.

Nextcloud News

An often overlooked part of your privacy is Google News (also part of Google Now). Each time you view an article there, Google can mine your interests and political views – similar to what Facebook does. And by now you should know where these things can lead.

Another drawback here is that the Google Algorithm will create a bubble for you by only showing content coherent with your current world-view.
I still prefer to manually choose the news sources – to create that bubble myself.

To do that, one usual subscribes some Web-feeds using a Feed aggregator like the Feedly service – similar to what Google Reader used to offer, before being killed by Google.

The go-to app here is Nextcloud News combined with the Android App for a pleasant mobile usage.

Music

Most of you are probably just stream music via Spotify/ Youtube Music, but keep in mind that these services merely rent the songs and as such they can arbitrarily disappear from your library.

Therefore, I like to have my own copy of the song. Unfortunately it is very inconvenient to juggle mp3s around for getting the music to various devices.

Google Play Music used to offer best of both worlds for me, where you could upload your own music files and manage your playlists in one place. Additionally, you could make the music available offline by pinning individual playlists on your device.
Unfortunately, that concept did not allow Google to arbitrarily inject ads into my music stream and therefore the service got killed as well.

Nextcloud Music to the rescue! This app picks up your music library via Nextcloud files and allows to stream that via the Browser or the Subsonic API.
This is where the DSub Android Player takes over. As with Play Music, you can either stream the library or pin individual songs/ playlists for offline use. Note: untick the “Authorization Basic headers” box when setting-up Nextcloud Music.

Other

If you clicked on the links above, you probably noticed the F-Droid alternative app store for Android.
Getting your apps there ensures that you are using verified packages and open-source software. You can easily use it alongside with the Play Store. If that is too inconvenient for you, all of the above apps are also available via the Play Store.

Finally, there is the web-browser. If you do not log in with your Google Account, using Chrome is mostly safe. However, I suggest switching to Firefox. See the my original article on that topic for details. In short; the main reason is the availability of extensions. Those allow you to block ads on the mobile web too and use Youtube in the backround.

Header Image: Digital Chains by stanjourdan (CC-BY-SA-2.0)

Mould King 13106 Forklift Review

I got myself the MouldKing 13106 Forklift, which is based on the MOC 3681 by KevinMoo and wanted to share my impressions with you.

First of all, MouldKing actually improved the set by exclusively using back technic pins instead of the blue ones like in the MOC. Also they are officially cooperating with the MOC designer – so he is likely getting some share of the sales.

The set comes with “New PowerModule 4.0″, which means it supports proportional output. If you use the new joystick controller (like I do in the video) or use the app, you can have smooth controls of the motors and not just binary 0% or 100% throttle as with the standard remote.

Watch this video on YouTube

As you can see, I actually put on some of the stickers. Some purists never do anything like this, because they argue that after some time the stickers start peeling off and look used. This is certainly a good point if you are building a sports-car – with a Forklift however, I would argue broken stickers add to the looks.

Compared to the original MOC, Mould King removed the lights, but added a pallet similar to the one found in the Lego 42079 Forklift.

Interested in getting the set? Support this Site by using the following affiliate Link:

Get this model on Amazon

Manual errata & comments

Generally, I prefer the Mould King manual to the original by Kevin Moo as I like renderings more than photographs. However, its nice to have the original at hand if something looks fishy. While building, I noticed the following:

Step 34: Cable-management is almost completely skipped in the manual. I laid all cables through the opening behind the threads. This keeps them out of the way later. The fiddle through the cables of the motors, that you add at steps 52 & 55.

Step 100: The battery-box position is wrong. It will collide with the bar you added at step 96. To make it fit, just rotate the battery-box by 180°.

Also, the direction of motor A has to be reversed. Press and hold left-shoulder, up and down for 3 seconds for this.

Step 111: The arms that you added in steps 89/ 90 should be oriented upwards to hold the footstep.

Step 143: Use a black bush instead of the 2-pin-axle beam, so things look symmetrical. This is a leftover from the original MOC, which squashed the IR receiver in there.

Step 156: Attach the levers to the front console at step 173 instead of attaching them to the seat here. After all they are supposed to control the fork and not the backrest.

Step 214: I suggest using gray 2-axles at step 230 instead of the suggested whites. This way the front facing axes will be all gray. For this just use white 2-axles here. Those wont be visible at all anyway.

Step 277: When adding the fork to the lift-arm, make sure that it has as much play as possible. Otherwise the fork will get stuck when moved all the way up.

Interior with fixes at step 143 & step 156

Step 278: Do not fix the threads yet. Wait until the end so you can correctly measure the lowest position of the fork (which gives you the length of the threads).

Step 286: Make sure that the 3-pin pops out towards the 8-axle. This will make joining things at step 288 much easier.

Comparing water filters

Lets say, you want to reduce the water carbonate hardness because you got a shiny coffee machine and descaling that is a time-consuming mess.

If you dont happen to run a coffee-shop, using a water-jug is totally sufficient for this. Unfortunately, while the jug itself is quite cheap, the filters you need will cost you an arm and a leg – similar to how the printer-ink business works.

The setup

Here, we want to look at the different filter options and compare their performance. The contenders are

Name	Pricing
Brita Classic	~15.19 €
PearlCo Classic	12.90 €
PearlCo Protect+	15.90 €

As said initially, the primary goal of using these filters is to reduce the water carbonate – any other changes, like pH mythology, will not be considered.

To measure the performance in this regard, I am using a digital total dissolved solid meter – just like the one used in the Wikipedia article. To make the measurement robust against environmental variations, I am not only measuring the PPM in the filtered water, but also in the tap water before filtering. The main indicator is then the reduction factor.

Also, you are not using the filter only once, so I repeat the measuring over the course of 37 days. Why 37? Well, most filters are specified for 30 days of usage – but I want to see how much cushion we got there.

So – without further ado – the results:

Results

Name	Ø PPM reduction	Ø absolute PPM
Brita Classic	31%	206
PearlCo Classic	24%	218
PearlCo Protect+	32%	191

As motivated above, the difference in absolute PPM can be explained by environmental variation – after all the measurements took place over the course of more than 3 months.

However, we see that the pricing difference is indeed reflected by filtering performance. By paying ~20% more, you get a ~30% higher PPM reduction.

The only thing missing, is the time-series to see beyond 30 days:

As you can see, the filtering performance is continuously declining after a peak at about 10-15 days of use.

And for completeness, the absolute PPM values: