Drop the beat - with John Park

Drop the beat - with John Park
By Paul Cutler (@prcutler) |

Welcome to the show

In this episode, Tod and Paul welcome John Park to the show. They discuss a floppy disk MIDI boombox, live-coding music, the RP2350 as a mini-computer, and more.

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Show Notes

Floppy Disk MIDI Boomboxes (John’s Pick #1)

AlgoRave (Tod’s #1)

My new favorite live music genre is “Algorave”. While it’s a term that’s been around since at least 2011, according to Wikipedia, I just recently came across it. Basically it’s “live coding dance music to a live club audience”. But wait.

You may think that watching nerds twiddling on laptops isn’t quite “live music” and you’d be right. In the mid-2000s, I went to a few clubs where people were playing on Monomes (those light-up gridded MIDI controllers controlling synths or laptops). They were on music stands, angled towards the audience. Seeing Monome button-lights change with the performer’s actions was much more engaging than just watching a laptop user bopping their head. Seeing computers unashamedly used live as musical instruments was new too. With the Monome, you could see the performer playing, see the device respond: it brought the audience in, showing how the performance worked.

Later we got great performances like Madeon’ Pop Culture and Shawn Wasabi’s Marble Soda on Launchpad or MIDI Fighter devices. Tese grid devices had become displays onto themselves. Yet there was still “distance” with the audience: you couldn’t see what these button presses were triggering.

And then there’s live-coding and algorave. Instead of hiding the laptop screen, it’s brought to the front. Live algorave performers project their laptop screens onto the club walls. And it’s not boring! These live-coding apps look more like something out of a Hollywood executive’s idea of “hacking”, rather than the standard GUIs we’re familiar with.

Picture: a screen of text, semingly random sections of it flashing in time with the beat. You see the performer’s cursor move and position over some text. It changes, the screen flashes, and the beat drops. Under and on top of the text are visual representations of the notes, the drums, the audio waveforms being played, making it difficult sometimes to make out the text, this code that is somehow also a musical performance. But then it scrolls again, changes, and the beat goes on. It’s hypnotic.

Now you can see both the performer and “instrument” they’re playing, but the instrument is code. That’s algorave and live-coding more generally.

If you’d like to try out live-coding and your hand at algorave, there are many apps to try! Most are free and open source. Several I mentioned back in Bootloader Episode 2 back in Oct 2022.

The one I’ve been using a lot for the last several weeks is called Strudel. It runs in the browser! An artist who’s working primarily in Strudel goes by the handle “DJ_Dave”. I remember DJ_Dave using Sonic Pi a few years ago, but now she’s all Strudel. Her Strudel live sets project the Strudel live-coding REPL screen on multiple walls, embedding you in the music code. She’s mostly active on Instagram and you can learn some cool Strudel tricks from watching them.

Watch some Strudel videos on Youtube. You can see the musical compositional thinking happen in real-time. It’s fun.

The RP2350 mini-computers are here (Paul #1)

Update: Just days after recording, Adafruit released the Fruit Jam. Paul has ordered one.

Adafruit has been teasing us for months about their mini-computer, the Fruit Jam, which they’ve been developing in the open even have a product page up for it. It features the rp2350B, 16MB of Flash plus 8MB PSRAM, with the PSRAM helping for emulation, microSD card, DVI output, headphone output, 2 port USB host for keyboards, mice or gamepads, 3 switches, and more. And if you’ve been following their development, they’re up to a Rev-D version that features a wifi co-processor, though I don’t see that on the product page.

But now a company named Olimex has beat them to the punch with a product that describes that doesn’t leave a lot to the imagination, calling it the RP2350pc. It too features the 2350b, 16MB of Flash + 8MB of PSRAM, but has 4 USB-A ports for USB-host, DVI/HDMI output, microSD card and stereo out AND in. It’s only €25, which seems really reasonable. It comes with a custom UF2 that looks to be running MicroPython and they market the Reload emulator for Apple II as well. There is a short manual that mentions their UEXT connector of which they’ve developed some plug and play modules that use this universal extention connector. They’ve also made the schematic and KiCad files available on GitHub, which is a nice touch. I looked at picking one up, but it was 23Euro to ship it, and that’s before any tarriffs.

CyberBrick (John’s Pick #2)

KiCad scriptability with kicad-cli (Tod #2)

Did you know you can use KiCad from the command-line? Let’s talk about using KiCad(“kee-cad”) PCB software programmatically.

Until recently (like for the last 20 years), I used Eagle to design circuit boards. It was pretty great. And it was made better back in 2011, when the community, including Adafruit’s Limor and PT, convinced them to change their binary file format to a text-based one. This made integration with version control systems like git much easier and a stable of tools to process Eagle files blossomed, making our lives easier.

When I moved to KiCad last year, I was pleased to see it also had a well-defined text-based file format. Script-based processing of KiCad designs, both in the app and outside, was standard practice. This enabled wonderful tools like various image importer & exporters, Stargirl’s web-based Kicad viewer, organic round trace generators, manufacturer part number to KiCad footprint generators, and exporters for popular PCB fabs.

But KiCad editing these files can be tricky, especially if they’re currently open. So I was really intrigued to learn about “kicad-cli”, a command-line tool that ships with KiCad. Using this tool you can do the obvious things like export Gerber and drill files for PCB production. You can also use it to import and export schematic symbols and PCB footprints. But you can also have it run ERC (electrical rules check) and DRC (design rules check) on your schematic and PCB on the command-line! This is like a syntax and linter for code, but for circuit design. It means you could add these to a github action, to ensure you never check in a bad schematic. This is incredibly cool.

The reason why I started looking into it is I wanted to do a visual “git diff” of a PCB design. The normal “git diff” will show you how the text has changed. This is great for code, but for a vector art design like a PCB, not that helpful. And the tools I found to do this were either part of monthly for-pay services or had huge dependencies and written for old versions of KiCad.

So using some tips from a KiCad forum post, I made a simple visual diff shell script that depends only on KiCad and a working web browser. It works by calling “kicad-cli” and asking to render two different versions of the PCB to SVG images and then some quick HTML CSS magic to animate a cross-fade between the images. It’s about 90% of what I want and with some changes to my git config, I can now “git diff” PCBs visually. It’s not a tool I use every day but it’s handy!

The return of the Commodore 64 (Paul #2)

YouTuber Peri Fractic, who runs an all things retro YouTube channel, has announced on a video on his channel that after 7 months of negotiations, he has a deal in place to buy the Commodore 64 brand for 7 figures. He’s created a public benefit corporation for Commodore 64, which means that while it’s not a non-profit, it has been founded to “preserve and promote retro-computing.”

And with that comes news that they’re selling a Commodore 64 Ultimate that you can pre-order now and is supposed to ship before the end of the year starting at $299. They claim it’s the first new Commodore in over 30 years and that’s because it’s not doing software emulation, they’re using a FPGA to re-create the Commodore hardware. There are 3 models, the BASIC Beige edition, a Starlight edition that adds a translucent case with sound reactive LEDs, and the Ultimate Founders Edition, of which there are only 6400 made for $500 and gold plated badges, gold keys, and more.

Each model has an HDMI port, built-in WiFi and USB to bring it into the modern era. They’re able to play any of the original C64 games and the description even claims you’ll be able to plug in old cartridges, CRT TVs or even disk drives.

August 3rd Update: The acquisition has been finalized.