@kbob@chaos.social
@kbob@chaos.social avatar

kbob

@kbob@chaos.social

Crusty geek. Retired software developer, aspiring musician. Used Unix way before it was cool.

Once I built a pumpkin chucker. Another time, I built an LED cube.

Interests: 3D printing and making in general, synths (playing and making them), learning the bass guitar (rock, jazz, funk), FPGAs and electronics, pinball. I spent 40+ years obsessively coding and studying computing, but that interest has finally cooled.

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kbob, to woodworking
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When you don't have a drill press...

kbob, to DSP
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I want to write a digital delay. Does anyone know of good info on how to use all-pass filters in delay lines for phase weirdness effects? Or any filters, really.

I'm planning on using a Teensy 4.x (Cortex-M7), so I won't have a lot of compute power.

Thanks.

@synths #synths #dsp

kbob,
@kbob@chaos.social avatar

@emeb @synths That entire article is gold. Thank you. I've been using chorus, flange, and delay for years, never quite understanding how they worked.

The big delay network in the reverb section looks interesting too. I saw a design very similar to that in the 1990s when I hung out with real DSP engineers.

There's a lot I don't know yet.

kbob,
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@emeb @synths You wouldn't have anything more cookbook-oriented, would you? I've got a project with a fairly short schedule, and I want some working code in the near term.

kbob,
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@emeb @synths

Teensy Audio Library has modules for flanger and delay. It might be the near term solution, at least for prototyping.

https://www.pjrc.com/teensy/td_libs_Audio.html

kbob,
@kbob@chaos.social avatar

@emeb @synths They don't have any all-pass modules. I'll have to make my own. That's still probably faster than writing the whole thing from scratch, though.

metin, to design
@metin@graphics.social avatar

Started a new modeling project…

Those who are as old… I mean… as experienced as I am, might already recognize what this is going to be. 🙂

More updates will follow.

kbob,
@kbob@chaos.social avatar

@metin That low-rez ray tracing is a neat visual effect in itself. It's great that it runs in real time.

kbob, to random
@kbob@chaos.social avatar

Adafruit sells ultraviolet Neopixel strips. Has anyone here seen any good projects using them?

How well can you tell which pixels are on when they're not visible light?

#Adafruit #Neopixel #LEDs #WS2812 #BlinkenLights #UV

smellsofbikes, to random
@smellsofbikes@mastodon.social avatar

A dubious idea I have about cutting curved dovetails so a box would look like an impossible dovetail box, but would in fact have the top open on an arc rather than a diagonal slide like most impossible dovetails.
The axis of rotation is the left corner, where there's a green line.

kbob,
@kbob@chaos.social avatar

@smellsofbikes Clever idea. The printer is busy, but I have STL files ready to send...

My rotation point is inside the box. The dovetails are just lofts, not proper conical surfaces, but I suspect they're within manufacturing tolerance.

kbob,
@kbob@chaos.social avatar

@smellsofbikes Done. As I said, I fudged on the math. Though I think the correct shape just a revolve of a trapezoid that's planar but doesn't intersect the revolution axis.

A box assembled from two dovetailed halves. The top is blue, and the bottom is yellow.

kbob,
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@smellsofbikes I decided to use Archimedean spiral infill to indicate where the center of rotation is. I spent more time tricking PrusaSlicer into putting the spiral center in the right place than I did modeling the dovetails.

In the end, I made the box part of a bigger object that has the rotation axis at its center. Then I cut away the unneeded part.

Blue is PETG on textured sheet; yellow is PLA on smooth sheet.

Two halves of a box with a large arrow-shaped protrusion sticking out from one corner. The circles in the infill are centered in the box plus arrow.

kbob,
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@mcdanlj @smellsofbikes If the box is square, and rotation axis is on the diagonal, wouldn't four cutters be enough because the surfaces on each side of the diagonal would have the same shape?

kbob,
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@mcdanlj @smellsofbikes Here's a picture that shows the same two tool edges each cutting two dovetail edges. They are indeed curved tool edges, but it's the same curve. So two tools can cut those two dovetails, and two more tools can cut the other two dovetails.

You should be able to intersect the tools' cuts with a plane that intersects the axis and get the tools profiles. (I have no idea how to convert that into an actual tool, though. I have never gotten into CNC.)

kbob,
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@oblomov @smellsofbikes It's not much to see, but sure.

I made the clearances loose, so it just slips together.

I pick up the two pieces of the dovetail box and rotate them together. Then I rotate them apart.

kbob,
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@mcdanlj @smellsofbikes Oops, yes, it's eight tools. Four tools for the tails, and four more tools for the slots the tails go into. Arrgh.

metin, to scifi
@metin@graphics.social avatar

Started a new SDF modeling project in MagicaCSG.

It's going to be a sci-fi drone. More updates will follow tomorrow.

#SciFi #ScienceFiction #drones #design #artwork #sculpture #3DModeling #illustration #illustrator #art #arte #artist #DigitalArt #ArtMatters #GraphicDesign #3D #MagicaCSG #CreativeToots #FediArt #MastoArt #ArtistsOnMastodon

kbob,
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@metin How much of this image did you have in your head when you started, and how much did you discover as you created it?

raichoo, to bass
@raichoo@chaos.social avatar

Nice! Logic 11 can do Stem Splitting now. This way I can remove the #bassguitar for tracks I'm doing a play along to. It's not perfect but already so much better than not having it. Wondering how well this is going to help me to transcribe stuff 🤔 #bass https://youtu.be/exLkvKjs3GQ?si=_0ZVai7JlSoCACtE&t=2077

kbob,
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@raichoo I've been using StemRoller, which is a free Mac/Windows app. I'll keep using StemRoller, as the new Logic stem splitting function is only for ARM Macs, and my iMac is Intel.

But yes. stem splitting is very useful. I can download any song and turn it into a bass-free backing track. I can download a song, load its four tracks into Logic, and use the mixer and EQ to bring out the bass as much as I need to hear it accurately.

thomasfuchs, to random
@thomasfuchs@hachyderm.io avatar

Gonna enjoy a bananum for breakfast

kbob,
@kbob@chaos.social avatar

@thomasfuchs I prefer the British spelling, bananium.

chris_gammell, to random
@chris_gammell@chaos.social avatar

I know the answer is "whenever the power company says is cheapest", but from a mental model perspective: is it better to plug in the car to charge on a sunny day where solar is generating excess capacity (on other roofs, not mine)...or better when the overall grid utilization is low, like in the middle of the night?

kbob,
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@chris_gammell It's better to plug in when your car's at home, not tootling around the shopping mall. (-:

That's a semi-serious answer. If you charge every day and drive every day, your car has limited hours in the garage.

Solobasssteve, to bass

A few people have asked me recently about in-person bass lessons, so I thought I'd better write about why I only teach on Zoom these days, and why I think it's actually better than the in-person lesson experience.

https://www.stevelawson.net/2024/04/why-i-only-teach-bass-on-zoom/

(lesson deets are at that link too)

kbob,
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@raichoo @Solobasssteve I use Zoom. My most frequent error is forgetting to sync my audio interfaces in the Audio MIDI Setup utility (MacOS). When I forget, the sound quality gradually degrades over the space of several minutes into complete chaos.

Here's a non-bass example, with and without interfaces sync'd.
https://chaos.social/@kbob/109525796747445600

metin, to 3dmodeling
@metin@graphics.social avatar

Time for a new hard-surface modeling project, using the trusty MagicaCSG 3D editor: a submarine.

As usual, I'll keep you posted of the progress.

kbob,
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@metin How about showing the sub from more angles? From behind, below, above?

kbob, to random
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I do not understand components and coordinate systems in Fusion 360. Because of that, I may have lost the design I've been drawing all week.

I changed a parameter, and half the things that should have moved did move, and half did not. Curves that had been closed were no longer closed, and things got worse from there.

It looks like parameters used in the Move/Copy command don't update? Do I have to use a rigid joint to fix every component?

Advice welcome.

kbob,
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@3dprinting ??? This was supposed to be a video. It looks like I just uploaded a still.

Video shows assembly of a three piece printed assembly that locks in place in a rectangular hole in a pressboard. It uses a sliding lock to grab the pressboard, and uses magnets to hold the LED bar in place.

kbob,
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@3dprinting I am still working on the printer enclosure when I'm not traveling. Today I made a test piece that slides along an IKEA LACK leg. I put steel dowel pins on two sides for a tight but low-friction fit. It works better than expected.

kbob,
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@chrishuck That's high praise coming from you.

kbob, to 3DPrinting
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I'm thinking about printing a flip-down MagSafe iPhone charger to mount under the kitchen cupboard. This is kind of the idea. I'm still working out how to route the cord. I'm imagining magnets to hold it in position either flipped down or flipped up, but haven't modeled those either.

kbob,
@kbob@chaos.social avatar

I redesigned this and published the new one to Printables. As the marketing department of Sirius Cybernetics Corporation says, Share and Enjoy!

https://www.printables.com/model/877897-flip-down-magsafe-iphone-charger

Video clip shows me reaching under a kitchen cupboard, flipping down a 3D printed MagSafe charger, and letting its magnets grab my phone. After the phone goes into desk clock mode, I reach out, take the phone, and flip the charger up under the cupboard.

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