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Episode 25 - I Feel the Need for Speed

Published: October 6, 2025

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Faster Raspberry Pis by ditching SD card w/ rpi-clone (Tod #1)

If you use Raspberry Pis regularly and you're still running them off microSD card, have I got a treat for you. Short version: use rpi-clone to a USB thumbdrive. You may know that Raspberry Pis running from SD cards get slower over time. SD cards can get flakey with age too. But SD cards are so easy to get a Pi going! But with a modern thumbdrive and the rpi-clone script, my Raspberry Pi 4 is faster than it's ever been.

I run a small group of Raspbery Pis for testing of my products and various CircuitPython builds. One RasPi 4 has four different CircuitPython boards permanently hooked up to it to test how different CircuitPython firmwares work. I noticed this server was getting increasingly slow. Git checkouts took twice as long, even logging in via ssh took a few seconds. There were no errors in the logs and the microSD was a high-endurance one. I had replaced it only a year or so ago. But I have been using this Pi a lot more lately too.

I know I know, all the "real" hackers have been booting their Pis off external drives forever. What took me so long?

I imagined it would be a daunting task, needing extra components like an NVME hat or an ungainly external drive enclosure hanging off the back. Fortunately, I'd just seen a video by the awesome Jeff Geerling where he off-handedly showed his rpi-clone script to turn a SD card-based Raspbery Pi into one that boots off external storage. Seemed easy, let's try it!

I got one of those small USB 3.1 thumbdrives. They're pretty fast. I used a $15 Samsung 128GB one that is just a nubbin when plugged in. With it was plugged in, I downloaded the rpi-clone script and ran it according to the README. It chugged, formatting the thumbdrive and copying over the Pi's filesystem. When done, I powered-down the Pi, removed the microSD, ta-da: it boots off the new drive!

This Raspberry Pi 4 server I've been using for five years feels like a whole new computer. It's like I got a free CPU upgrade. And to prevent this thumdrive from degrading faster, I'm going to be putting the logs directory into a RAM disk using log2ram. The constant writing of log files really wears out solid-state storage the fastest. I'm also looking into tiny SSDs for my other Pi servers. For my Pi 5, there's the official NVME SSD hat I may try. I'm now on a quest for the tiniest SSD solution for Pi4s.

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For more performance improvements:

InvenTree (Paul #1)

Back in Episode 17 I share Inventory, an open source inventory system for makers and manufacturers that had just released their 1.0 release.

Thanks to Alec Delaney (aka Tekktrik), I came across an app called InvenTree, a play on the word Inventory, which also just released their 1.0 release after 8 years of active development.

Inventree includes a number of features, including:

  • Organize your parts and sort them into different categories for your parts
  • You can manage suppliers related to each part
  • Stock locations, which are real world physical location for your parts
  • Bill of material management, allowing you to define a list of parts to make an assembly
  • Custom reports about your inventory based on a number of templates and it uses HTML templates to create PDF reports for you

Inventree also includes a robust plugin ecosystem. There are plugins maintainted by the core team as well as the community. There are plugins for just about everything - there’s integration for Digikey and Mouser, there’s a plugin to locate your physical stock locations with WLED, which is pretty neat, and a bunch of plugins to use with your printer.

Inventree is written in Python using the Django web framework and plugins can be written in Python, too.

There’s also excellent documentation covering everything you might want to know. It’s detailed and covers all of the features. And lastly, if you want to take Inventree for a spin before installing it, they have a full featured demo instance. I logged in and tried it out and I came away really impressed.

Framework 12 laptop (Tod #2)

If you're looking for a Linux laptop, I highly recommend the Framework 12. As the name implies, it's a 12" laptop. You can buy it fully-assembled or as a "kit", where "kit" means you get to install the RAM, SSD, and expansion cards (more on that in a bit). The assembly is easy and gives you the chance to see the inside of the laptop and the care that went into it. You can see that Framework designed the whole machine for repairability. In fact, on their older Framework 16, they just introduced a new AMD Ryzen mainboard with NVIDIA RTX GPU you could swap in.

So to "assemble" my new laptop, I got a beer ready and everything. I mean, I say "everything", but they included the one screwdriver needed. I only got about two sips in before I was done. You install the RAM & SSD from the top, by lifting the keyboard. It connects via pogo pins and magnets so no cables to worry about. Just snap them in, then snap on the keyboard. The keyboard is then secured by captive screws on the bottom. It's a really nice design and even with all that, the laptop is still only as thick as my main MacBook Pro. Apple, replaceable SSD & RAM!

There are many Youtube videos that deep-dive into this laptop, its features and how it performs, so I won't go into those aspects. Suffice to say, it performs as well as other Intel i5 laptops and costs about the same.

In Linux it's fast and does all the things I need it of it: web browsing, video playing, code editing, compiling, PDF viewing, etc. The recommended standard Ubuntu 25 install works great, with all peripherals recognized and when I plug in class-compliant USB devices like USB audio or MIDI adapters, those work as expected. I've been using it for a little over a month and haven't had a problem.

There are two things about this laptop that really stand out to me, and I've been trying to do Linux on laptops since the 1990s.

(Anyone remember linux-on-laptops.com? It was where we huddled in the cold, sharing campfire stories of almost getting audio working on corporate Toshiba Satellites or Dell Inspirons. Now we have Linux-first companies like Framework, MNT, and System76. But if you're scarred from past attempts to get Linux working on a laptop and you have an old Thinkpad or Dell from the last few years, there's a good chance it'll work great today and seem much faster than the Windows that was on it)

Anyway, the first really cool thing about the Framework 12, besides it being just fully working modern laptop on Linux, is the four expansion card slots on the sides. These are essentialy recessed USB-C ports and the available expansion cards either expose that USB-C port or USB-A or Ethernet, HDMI, extra audio, SD card, or storage. It's really neat. It totally gives that "I'm plugging in a cartridge" vibe and lets you customize the laptop how you want. My current set of cards is two USB-C, a USB-A, and HDMI out. Any USB-C card is also a charge port.

The other neat thing about the Framework 12 is that the screen folds over onto the back and it turns into a tablet. And the touchscreen even works on Linux! Even though most of my uses aren't touch-compatible, it's really handy to have up an instructional video or schematic on the "tablet" screen while I'm working. They just introduced a stylus that works when the laptop is in tablet mode. I don't have this yet and don't even know if it's supported under Linux, but it's $60 so I may just get it to see what it can do.

Oh, and KiCad absolutely flies on this thing. Using a stylus with KiCad on Linux would seem very sci-fi to me.

This review isn't sponsored in any way. I'm just happy to have a good portable Linux box made by a company that cares about repairability and upgradeability. Thanks Framework

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Channels DVR (Paul #2)

This next one is one of my favorite pieces of tech in my house and it just keeps getting better. I cut the cord and got rid of cable TV probably close to fifteen years ago. I’ve tried a number of solutions over the years since then for watching live TV with an antenna, including MythTV, Kodi and Emby, but there is one piece of software that I think does it better than any of them, and that’s an app called Channels.

First, you’ll need an antenna to get over the air stations that you hook up to a device called the HD HomeRun, which is a digital network tuner. You plug the antenna into that, and the TV signal is now available over your network. Antenna prices vary, and an HD HomeRun box will run you about $100 - $150 depending on which model you choose. If you visit RabbitEars.info, it will show you a list of all the channels in your area that you can get via antenna - and you’ll probably be surprised how many channels there are.

Next, you’ll need to subscribe to Channels for $80 a year, which is $10 more a year than Plex. Then you download the Channels DVR server software, which is available for Windows, Mac, Linux, Docker, and a number of network attached storage devices, including Synology, Netgear, TrueNAS and a lot more.

You can watch Channels on your TV using an AppleTV, Android TV, or an Amazon Fire Stick. The apps to connect to Channels and watch it on your phone or tablet on iOS or Android are all free. And they make it super easy to watch it on the go away from home and just stream it over the internet to your device.

But it’s not just a DVR - you can manage all of your personal media on it as well. I have a large physical media, with a ton of DVDs and Blu-Rays I’ve ripped, and I’ve imported them all into Channels.

Channels continues to innovate: * Virtual Channels * Multiview * Skip intros and credits

There may be cheaper solutions out there for your DVR, but few are as polished as Channels. I’ve been using it for years and it’s one of my favorite apps that I use.

Mutable Instruments synths ported to Arduino Pico (Tod #3)

If you've ever played with Eurorack modular synths, you know the name Mutable Instruments. Mutable was created by Émilie Gilllet back in 2009 and every one of her synth modules was interesting and useful. They ran the gamut from oscillators and filters and reverbs to envelopes and utility modules like mixers. And now you can run some of the in Arduino on a Pico!

Friend of the show and previous guest John Park has an almost complete collection of Mutable modules and it fills up two racks of space. He can create such wonderful noise with them all!

Because Mutable modules are useful and beloved they became standard kit for anyone doing modular. And because all of her designs are open source, several other bespoke manufacturers made versions of her modules in different form-factors or with added features. I've got a few Mutable modules and a few clones. For instance, I have a clone of the reverb module Clouds called Supercell that adds extra knobs and inputs to control even more of the reverb sound. I also have a clone of Braids, one of Mutable's most popular synth modules, that's in a much smaller size.

And some of Émilie's algorithms made it into professional synths like the Korg Microfreak and the Polyend Synth. You may not know Mutable but I bet you've heard the sounds.

Émilie shut down Mutable Instruments in 2022 but her legacy lives on in all the modules, repos, and inspiration her circuits and algorithms have created. Thank you Émilie I've learned a lot about analog electronics from you.

I've long wanted to poke around the synth and effects algorithms Émilie created, but most of her modules were written for STM32 chips, a chip type I'm not that experienced in. Fortunately, Mark Washeim, aka @poetaster on github, has ported some of the Mutable module's code to Arduino on the Pico. This is great! I know that well. It's one less barrier for me, and I've just started poking around and trying stuff out.

If you want to start playing with this stuff immediately, poetaster/Mark also has a little Pico-based synth board he sells on Tindie called "scarp" that he targets for his Mutable porting experiments. It's got an OLED, two pots, and 8 buttons w/ LEDs. I was pleased and surprised to see my name called out as he based some of the design of scarp on the various synth boards I've made over the years. Thanks Mark! I can't wait to get deeper into the Mutable synth code. Links to all this stuff in the show notes.

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Dissolvable 3D Printed Circuit Boards (Paul #3)

Researchers at the University of Maryland have developed a new type of circuit board using polyvinyl alcohol which can dissolve in water. To create the wiring on the PCB, they injected a gallium-indium metal alloy into the circuit board's channels in liquid form and then manually placed the components on the board. They then apply a polymer glue to seal the circuits before drying the device for an hour at 60 degrees Celsius.

Using this process, the researchers created working versions of a Bluetooth speaker, a fidget toy, and an electronic three-finger gripper. A splash of water won't hurt the circuit board - it takes up to 22 hours at room temperature to dissolve, and the researchers were able to recover 99% of the dissolved polyvinyl alcohol.

According to a 2022 United Nations report, Asia generated 600,000 tons of used circuit boards while recycling only 17%. Europe and North America generated 300,000 tons and recycled 61% in Europe and 44% in North America.

Imagine how many hobbyists create PCBs for prototyping and what happens when you get something wrong and have to throw the board out? This process might start to address that. Not to mention that if you can do this with a 3D printer, you can speed up the prototyping process by a huge factor.

Unfortunately, you'll need a subscription to read the article either on Apple News or at the New Scientist website.