WRITTEN_BY David REVOY -
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31 comments
Hey everyone, I'm taking a break from my usual digital painting topics to share a special DIY project. I'm not sure who this will help, but I think there's a place for it on my blog somehow. Who knows, maybe it will spark some ideas for your own DIY projects.
Recently, during a routine health check of my four cats, I found out that one of the band might have heart problems, the younger one "Geuloush". I'll tell you right away **he's fine**, everything is fine, but he just has a little abnormality that needs to be monitored.
[](data/images/blog/2025/2025-04-24_digital-stetoscope_for_cats_01b_routine-check.jpg)
_Preparing the annual vet routine for the four cats._
So, after a long trip to a specialized vet's office, one in France with an expensive animal echocardiogram (which was an adventure in itself) I was told to monitor his heartbeat monthly. The vet's advice was to just put my finger on his pulse and count, but I was skeptical. I mean, cats have a heartbeat of 140-220 bpm, that's ridiculously fast! The vet seemed confident that it could be done and I was a little too washed up from the whole experience to question the thing. You see, the echocardiogram was a bit of an ordeal: it took all the morning, my cat was covered in echocardiogram gel, and we were in an operating block shared with dogs. So I just nodded and agreed that I'd do my best.
[](data/images/blog/2025/2025-04-24_digital-stetoscope_for_cats_01c_the-specimen.jpg)
_"Geuloush", the star of this article, knows the most charming positions._
Needless to say, when I got home, I realized that manually counting my cat's heartbeat was impossible. I tried the online tip of counting for 15 seconds and multiplying by four, but even that seemed daunting. So I started looking for a machine that could do the job for me, like the one the vet had in his office. But to my surprise, these machines were very expensive and mostly aimed at vet offices.
That's when I decided to get creative and go the DIY route. I figured that if I could just hear the heartbeat more clearly, I might be able to use some audio magic to count it. I picked up a cheap stethoscope (less than 10€) and a low-quality lavalier USB microphone I already had that worked plug-and-play on my Linux machine (around 10€ too).
After doing some research, I found a lot of helpful videos on the subject that showed me how easy it was to attach a microphone to a stethoscope. You just cut the rubber tube and put the microphone inside. Voilà.
[](data/images/blog/2025/2025-04-24_digital-stetoscope_for_cats_03_the-stetoscope.jpg)
_A lavalier mic inside the tube of a stethoscope: the USB stethoscope! Peak DIY._
And with that setup, I was able to record my cat's heartbeat using Audacity on my Debian KDE machine. Of course, getting my cat to cooperate was a challenge. At first, all I got was a lot of loud purring that masked the heartbeat sound. But I was patient, and after a few minutes he fell asleep and I managed to get a clean recording.
[](data/images/blog/2025/2025-04-24_digital-stetoscope_for_cats_02_sleeping.jpg)
_He didn't even realize he was sleeping on this metal thing._
[](data/images/blog/2025/2025-04-24_digital-stetoscope_for_cats_05_15sec.jpg)
_Audacity hint (red framed): you can toggle the lower view duration to see the length, it helps to select exactly 15 seconds._
[▶️ Audio sample: listen the heartbeat of my cat (15sec, ogg)](https://www.davidrevoy.com/data/images/blog/2025/2025-04-24_digital-stetoscope_for_cats_05b_15sec-audio-sample.ogg)
From there, I cropped a 15-second sample, took a screenshot of the waveform, and used Krita to highlight the most obvious beats. Then it was just a matter of counting and multiplying by four to get an approximate measurement:
**41 counted x 4 = 164bpm. **
All is well, he is a relaxed cat 😺.
[](data/images/blog/2025/2025-04-24_digital-stetoscope_for_cats_06_paint-over.jpg)
_Counting the beats, highlighted here for the blog-post._
I'll be tracking these measurements in a LibreOffice Calc spreadsheet, complete with a graph, so I can keep a close eye on my cat's health.
That's about it! It's not the most conventional DIY project, the DIY part wasn't even really exciting or challenging, but it was an interesting challenge to count the beats per minute of a cat, and I was able to get something that works. I hope it inspires someone else to get creative with everyday problems. And if you have more ideas on how to improve this rig, I'd love to read them.
## Update
2025-04-27: Thanks Hackaday for [the featuring](https://hackaday.com/2025/04/27/quick-and-easy-digital-stethoscope-keeps-tabs-on-cat/)!
2025-04-29: Thanks to [a comment by Nia Valentine](https://framapiaf.org/@daughterofrao@weirder.earth/114415392045138030), I tried the automatic bpm (beat per minute) analysis with the software [mixxx](https://mixxx.org/download/). At first, I was skeptical, because I already tried to detect beats with the CLI software [bpm-tools](https://www.pogo.org.uk/~mark/bpm-tools/) and didn't get a result close to the manual counting.
The difference: mixxx has an option "Assume constant tempo" that you can disable in the settings. After that it does the job pretty well and as easy as just playing the audio. It found 169bpm on a longer sample, which is close enough to the 164bpm I found manually. So I'm validating this approach. That's very good news because it simplifies the counting process and also the trimming of the audio to exactly 15 seconds. I can now sample a larger amount of good quality audio and let mixxx do the work. More info in the [mixxx beat detection documentation](https://manual.mixxx.org/2.5/en/chapters/preferences/beat_detection).
[](data/images/blog/2025/2025-04-29_digital-stetoscope_for_cats_05_mixxx.jpg)
_The user interface of Mixxx, loading a longer sample, my mouse cursor is over the bpm analysis number._
WRITTEN_BY David REVOY -
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23 comments
I'm excited to share with you a significant update I've made to my digital archive. I've been working on re-releasing around 25 of my 'best-of' digital paintings from before 2012, under a new license. Previously, they were available under Creative Commons Attribution Non-Commercial Non-Derivative 3.0 (CC By-Nc-Nd 3.0), but I've now updated them to the more permissive Creative Commons Attribution 4.0 (CC By 4.0).
To make them more accessible, I've even uploaded the full high-resolution, in lossless quality to the Pepper&Carrot artworks gallery, under the "Misc" directory (and at the bottom, because before 2012). [Gallery link here](https://www.peppercarrot.com/en/artworks/misc.html#2013-04-28_peacock-dragon_by-David-Revoy).
Some of these artworks, like my award-winning "[Alice in Wonderland](https://www.peppercarrot.com/en/viewer/misc__2010-07-21_Alice-in-Wonderland_by-David-Revoy.html)," (2010) were already available under CC By since 2022, but didn't have a proper home to host the lossless file. Others, like "[SpiderHarp](https://www.peppercarrot.com/en/viewer/misc__2006-11-19_Spider-Harp_by-David-Revoy.html)" (2006) and "[Fantasy Landscape](https://www.peppercarrot.com/en/viewer/misc__2007-01-30_Fantasy-Landscape_by-David-Revoy.html)" (2007), had never been shared in their full resolution online before.
You'll also find my portrait of Charles Darwin in the collection, which I'm thrilled to say was recently on display [in an exhibition at a museum](https://www.davidrevoy.com/article1073/my-portrait-of-charles-darwin-is-in-a-museum-now). This whole project was inspired by that, after seeing that photo of an old artwork from 2012 inside a museum, which got me thinking about the importance of digital conservancy and preserving my art for the long run.
It took me all the evenings of this week to update the old blog posts, dig out the high-resolution files from archived DVDs, and convert them, but it was worth it. Some pieces are over 20 years old... It made me realize all the time I've spent in my life with a stylus in my hand, painting, painting, painting.
I hope you'll find something in this list of artworks that inspires you to create something new, whether the project, medium, a print, or something completely different. On my side, I'm happy to share this 'vintage' pieces with you in a new way. 💜
**[→ 📦 Gallery link](https://www.peppercarrot.com/en/artworks/misc.html#2013-04-28_peacock-dragon_by-David-Revoy)**
[](data/images/blog/2025/2025-04-17_maintaining-my-vintage-digital-paintings.jpg)
_An overview screenshot of the concerned digital paintings_
WRITTEN_BY David REVOY -
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95 comments
I'm super excited to share this with you: my artwork is now on display in a museum. I just received a photo of the room of the exhibition with my [portrait of Charles Darwin](https://www.davidrevoy.com/article145/portrait-of-charles-darwin), and it's huge and looks amazing in this setting. This is a piece I painted in 2012 with the software Krita and the portrait is made up of many species from the evolution, kind of like a modern take on Giuseppe Arcimboldo's style, but with a twist dedicated to the famous father of the "On the Origin of Species".
It's part of the "COMPASSION" exhibition at the MAS in Antwerp, which runs since January 31 and to August 31, 2025. The exhibition is all about compassion and helping others (what a chance to be part of that!) and it features a mix of ancient and contemporary art, objects, and music. My art is on the same room than the "Declaration of the Rights of Man", what a honor!
If you're in the area of Antwerp (Flemish Region of Belgium), you should totally check it out. The museum is open from 10:00 to 17:00, and you can even take a guided tour. Tickets are €12 for standard admission and €8 for a discount.
I'm really proud to have my work included in this exhibition, and I hope you'll go see it and let me know what you think or send me a picture, because unfortunately, I'll can't travel to this place until the 31 August.
All in all, it's a dream come true for me to see my art in a museum 🤩, thank you MAS and the exhibition team for that.
Links:
- https://mas.be/en/
- https://mas.be/en/compassion
WRITTEN_BY David REVOY -
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12 comments
## Hardware review
The full test of how the overlay surface feels, pressure sensitivity, tilt, as well as a scratch and pressure test can be found in the video below:
[youtube]ZkZ-sSz65rU[/youtube]
**Direct video links**:
- On Youtube: https://www.youtube.com/watch?v=ZkZ-sSz65rU
- On Peertube: https://peertube.touhoppai.moe/w/7hiPUYqJVAnpAfSsS5oQzo
This article accompanies my video review of the Huion Inspiroy H610X, a medium-sized screenless pen tablet. The video provides my in-depth look at the device's hardware. This blog post, on the other hand, focuses on the information and technical aspects of installing and configuring the device on a GNU/Linux operating system.
**Official links**:
- Huion store: https://bit.ly/3F6Xa9O
## Out of the box situation
What features are available out of the box? Basically, **all primary functions are operational**. In the absence of a dedicated driver, the Huion H610X emulates two standard devices: a generic pen, similar to those used with laptop-tablet PCs, and a standard keyboard for key input.
Modern versions of GNOME and KDE, running under Wayland, can accurately detect the stylus coordinates and set the screen aspect ratio (with a bit of tweaking for Plasma, see screenshot later). Under X11, the xsetwacom command line utility can achieve similar results.
The limitation of this emulation is that most of the shortcuts for the stylus buttons and pad **buttons are hard-coded and cannot be changed** without a dedicated driver. The default key mapping is shown in the figure below (see image). While not ideal, the default shortcuts are still useful. However, you will need to get used to using a pen without a second top button (eg. to put a right-click on it), as an "eraser mode" is activated and hardcoded by holding down the button instead.
**Erratum:** the picture shows a Ctrl+Z on the last button, it's a Ctrl+Alt+Z by default (thanks to Erika in the comment section).
[](data/images/blog/2025/2025-03-18_huion-h610x-review_01.jpg)
_Default buttons layout when connected to a GNU/Linux machine_
## The proprietary driver
I have not tested or used the Linux proprietary driver provided by Huion, for ethical reasons. However, I am aware that many users may find its existence beneficial and may choose to make an exception to use this binary blob, prioritizing convenience. I do not judge their choice.
Link: https://www.huion.com/download/
## The FLOSS driver (udev-hid-bpf)
### Still Work in Progress!
I reported the device here: https://gitlab.freedesktop.org/libevdev/udev-hid-bpf/-/issues/61 , but due to a line-break issue in the export of Konsole, I'll have to redo it.
### Issue: Second Stylus Button Hardcoded Erase Mode
As a device compliant with [a Microsoft stylus standard](https://learn.microsoft.com/en-us/windows-hardware/design/component-guidelines/windows-pen-designs), one of the two buttons of the stylus will switch to a eraser mode by default. On Linux, this behavior was implemented at a kernel level and no graphical or cli tool can customize this behavior. That's why the button might appear as customizable on the GUI of Plasma on Wayland, or GNOME on Wayland, or X11 xsetwacom CLI tools, but it will not be possible to change this hardcoded eraser mode into, let say a simple right-click.
When this new behavior appeared, every tablets started to receive a custom fix: remove the hardcoded eraser mode and replace them by a customizable button. But after too many devices reported, it was decided to handle the problem differently: [a merge request for libinput](https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1158) with a code that would allow the user to make the hardcoded Erase Mode map-able as a button. Unfortunately, it might take a long time before reaching the end user: the merge request needs to be accepted on libinput and merged, then a libinput release needs to be made with the new code, then the distribution needs to package this new version of libinput on their update, then the desktop environment like GNOME or WAYLAND will probably need to adapt their System Settings GUI for the tablet to offer this new option.
In short, while it's probably a change that is brilliant on the long term, it will probably benefit the Fedora and Arch user first in a optimistic 6 month from now, and 2 years for Debian or Ubuntu-based users.
## Customization
### On Plasma Wayland
On Plasma Wayland, the tablet went totally undetected. Worst: the active area was detected as a square. While it was possible to manually resize this area, it was difficult to setup a "set proportion" to the display.
The device could still be used, but not in a professional way.
[](data/images/blog/2025/2025-03-18_huion-h610x-review_03_plasma.png)
_screenshot of the tablet system settings of Plasma 6.3_
### On GNOME Wayland
I was surprised to see the device listed on the tablet settings (Fedora), but there was a problem: two devices were listed, and the "button 2" has no effect (that was predictible). The buttons of the pad were not listed for customization.
The device could still be used, but not in a professional way.
[](data/images/blog/2025/2025-03-18_huion-h610x-review_02_gnome.png)
_Huion Inspiroy H610X on GNOME Wayland._
### On X11
That's what I used for the review and for the demo videos and I could get a good enough comfort to start working with the device.
For this part, I'll directly redirect your to [the Inspiroy H610X review and technical blog post](https://raghukamath.com/huion-h610x-graphic-tablet-review-and-setup-on-linux/) made by Raghavendra Kamath AKA ‘raghukamath’ , a well known Krita contributor (and friend).
His post is a gold mine for setting up the Inspiroy H610X on Linux, X11. Just mind that since Raghukamath wrote it, there was some update with the recent kernel and the Microsoft specification for tablets (what I already detailed here before). So the second top button of the stylus will be a hardcoded "eraser mode".
## Conclusion: contribute?
That's all, this guide can be of course continued or updated! You can send me your tips via comments, or on various threads mentionned in this article or via email.
WRITTEN_BY David REVOY -
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55 comments
[info]This post was an April Fools' Day prank! A big thanks to those who played along and to all the fun comments, and sorry (not sorry) for the Rick Roll.[/info]
I'm excited to announce the release of **Kiki Ultimate Digital Painting Companion**, a plugin for Krita that brings a personal assistant to your screen. Kiki watches your every move, offering remarks and occasional words of encouragement (but mostly sarcasm).
I developed it on the top of a new, free/libre, and open-source engine I named KUDOS (for Kiki's Ultimate Digital Oversight System) trained on my collection of many comments I read on the internet about the common issues and pain while learning to draw and paint. So, it's not based on AI or LLMs, but on a larger and limitless dataset: user frustration.
Kiki Ultimate Digital Painting Companion is still in beta, but I've already received great feedback from my beta-testers.
> "She's like having a permanent art critic on my screen, but without the constructive feedback." said one user.
Now, I know what you're thinking: **Is this plugin really useful?**
And to that I say... well, not really, but it might be? My plan right now is to get the plugin in the hands of as many users as possible, generate some buzz and hype, attract investors and then figure out how to monetize it later. After all, I'm just following the current way of making products in tech.
## Screenshot gallery
Once activated, Kiki will pop up right at the bottom of your screen and start commenting on what you are doing. Here are some examples:
[](data/images/blog/2025/2025-04-01_april-fool_c_net.jpg)
[](data/images/blog/2025/2025-04-01_april-fool_b_net.jpg)
[](data/images/blog/2025/2025-04-01_april-fool_a_net.jpg)
[](data/images/blog/2025/2025-04-01_april-fool_d_net.jpg)
## Upcoming features
- Kiki preventing you from painting on the wrong layer
- Kiki screaming at you to save your work
- Kiki sleeping on your screen if you paint too late
Your suggestions are welcome!
## Download
Ready to try Kiki Ultimate Digital Painting Companion Krita plugin?
→ [Click here to download the beta plugin](https://www.youtube.com/watch?v=dQw4w9WgXcQ)
Sources:
- [Git Repository of Kiki Ultimate Digital Painting Companion](https://www.youtube.com/watch?v=dQw4w9WgXcQ)
- [Git Repository for the KUDOS engine](https://www.youtube.com/watch?v=dQw4w9WgXcQ)
## License
[AFPL 1.0](https://github.com/colinodell/afpl/blob/main/LICENSE.md)
**Design:** Based on Kiki the Krita Mascot, made by Tyson Tan, and distributed under the Creative Commons BY-SA license.
