CircuitPython Day 2026

0:00Welcome to the Circuit Python Show. I'm your host, Paul Cutler. This episode is a replay of my other podcast, The Bootloader, and the live stream Todd Curtin and I recorded on Circuit Python Day 2026. We do use video and screen sharing so you may want to check out the video on the Aida Fruit YouTube channel, which I've linked to in the show notes. And with that, here's the episode. Welcome to The Bootloader. I'm Paul Cutler. And I'm Todd Curt. If you haven't heard of this, we're the host of The Bootloader podcast, which you can find in your favorite podcast player on the first Monday of each month or at The Bootloader.net. The show works like this. Paul and I each have brought a few things to share, all about Circuit Python for the last year.

1:00And a big thank you to Liz, who's on camera control. Paul, let's break down some of the numbers. Yeah, it's crazy that another year has gone by already. Since last Circuit Python Day, Circuit Python 10 was released in October with a ton of improvements. This was the first release to add some audio effects, full fruit jam support, including the new CP save partition for SD cards, and a bunch of graphics updates, including better Pico DVI support to work on more monitors. Okay. It's going to be like 100 degrees today, I think. So what was Circuit Python to you last year, Todd? So last year, Circuit Python 9 was all about SynthIO. It was like when SynthIO really got going and really got good. It kind of existed before, but it was like we had to try to figure out how it worked right. But like with Circuit Python 9, we could make real interesting sense in Circuit Python. This year, it's all about audio effects because a synthesizer voice by itself is just okay. But having audio effects after that, like delay and reverb, chorus and like that, like version 9 had echo, chorus and reverb created by Mark Gambler.

2:03Thank you, Mark. But then very soon after that, like right after 9 was released, and I think for the 10 beta is Cooper added multi-tap delay, phaser and distortion, and like both kinds of distortion, like a simple clipping distortion, but also like the sort of soft overdrive distortion. And then Cooper made some really important changes to how the effects works. We can chain them together. It was kind of hard to do that before. And so now you can basically plug them together like guitar pedals, which is great because it kind of matches how SynthIO works. SynthIO kind of looks and acts like a semi-modular synth where you kind of connect little cables together to make a synthesizer. So it's like we've got this modular synth on one hand and now we've got a guitar pedal board on the other. So it's all becoming really interesting. And then earlier this year, Tim, a K foaming guy, added a granular pitch shift to complement the pitch shift effect that Cooper had earlier. Both relevant pitch shift uses less resources. Grinial pitch shift can sound better for like larger pitch shifts. And then also the audio module, the audio mixer modules updated. So it's a level in pan knobs can be modulated with LFOs.

3:05Oh, and then I mentioned that all these effects have parameters that can be modulatable with SynthIO LFOs. They're like LFOs are like automated knob turning. So you can have things on your synthesizer or now audio effects that can automatically have their pan shifted or their distortion amount changed, things like that. And then to bring it home, earlier this year, Tim added the audio I2S in module. And now the audio duplex module, or if you want to call it, but it's let you can, both of them let you do stereo audio into circuit Python as well as playing audio out via I2S to get high quality 16 bit audio. And so now we can truly have circuit Python based guitar pedals or effects boxes, which you might have heard a couple of years, a couple of hours ago when Cooper was demonstrating that. And also just in the last episode, what are these segments called that we're doing on circuit by the day? Live stream. Last, last live stream. There we go.

4:06Tim demoed how he had hacked the teenage engineering team handheld effects unit with the entire alternate circuit Python firmware that lets you do cool real time effects of your voice. And so it's like circuit Python and commercial product and it sounds cool and it's fun to play with. It is cool. I can't create music, but it's been really fun watching the different projects that you Cooper and Liz at the audio effects. Yep. So after 10.0, we then saw 10.1 in February and 10.2 this past April. 10.2 included the latest ESP IDF as well as the micro Python 1.27 merge. So thanks to Dan for keeping up with upstream. Yeah, thanks. Thank you to micro Python, which made all this possible. I like that circuit Python is still merging in updates to micro Python as time goes on. I think that's pretty hard to do because circuit Python has deviated a bit. So I think Dan's been the one who's mostly responsible for the merges of thank you to Jesus. That must be a really hard task.

5:08So Paul, was your first one for this show? If there was another theme over the last year, is that it was the year of the fruit jam. This credit card size circuit Python powered micro PC was a hit. It was first released in July of 2025, but it was hard to find the first few months. And then the last eight of box late last year, eight of fruit shipped them to all the subscribers. I'm not going to go into all the hardware specs. You probably know them by now. But Todd, let's share a few of our favorite fruit jam apps from the last year. My favorite is probably Sean Carolyn's Pac-Man clone originally written for the wheel terminal Cooper Delrimuel ported it to the fruit jam and upstreamed it to Sean. Sean vibe coated Pac-Man in an afternoon and it's a fantastic port. I had him on a recent episode of the circuit Python show and he shared where he got the game resources, how he recreated the sounds of Pac-Man and more. I'll have to admit to losing a few hours just to playing it. Yeah, it's it's a I find it really fascinating. I got myself on the wrong screen. I found it really fascinating that we're at this stage were able to recreate old hardware

6:11in Python running on a chip. No OS involved, no super high powered system. You know, there used to be if you want to do emulators yet to get like a really powerful desktop computer thing. Right. Now it's like, oh yeah, we can do this on a thing that you know, fits in your hand. What was one of your favorite fruit jam things this year? So for me, that was the Zork player. So if you if you're unfamiliar, Zork ran on this thing called Z machine. It was a virtual machine created in 1979 to run many of the text adventures created by InfoCom. InfoCom, they did Zork, they did history, I just got to the galaxy, they did a ton of games. I can fact on this webpage, Dan has a picture. And the cool thing about this Z machine virtual machine is that let InfoCom get put Zork and all these other games on all the platforms of the 1980s, like the cumbersome for the Atari ST, the Sinclair X-A-D1, I think you meant.

7:11And thanks to that, Dan was able to be the same with the fruit jam. His port has that cool retro CRT 80 by 24 green screen CRT effect. I think for in Maximum this nostalgia, you should hook your fruit jam up to a CRT, you know. But Dan wrote to this Z code parser in circuit Python instead of C, which is what most people have been doing for the last 40 years, whatever. And it works nicely with the fruit jam OS, which if you have the circuit Python based OS, but ready in OS is in circuit Python, right? But if you if you rent service fruit jam OS, it works nicely with that. So it just becomes another app for your fruit jam. And it's a lot of fun to use this as just Zork and Z machine because it's the first chat system that we normal folks got to have access to. And learning how to use how to play Zork was and how to use the language that Zork once is kind of not that different from the prompt engineering we've had to learn recently of like, how do I phrase this thing so the LM will spit out something that that will

8:15work. And so now you too can be eaten by a grue or get lost in a maze of twisty passages, like 1980s kids. Yeah, I was terrible at Zork, but Dan was busy. Yeah, yeah, yeah, he's he's been doing a lot. In addition to the Z machine, he also released a handful of classic screen savers and another game moon writer. Yes, yes, yes. It's related to the classic lunar lander game from the 80s. Your mission is to retrieve minerals from the moons around the solar system. It's all physics based. You try to land your rocket ship based on how much thrust you're giving it and the gravity below. You need to make a safe landing to harvest the minerals and you can't tip over either. I'm not good at Zork and I'm not good at physics games either. Yeah, this one, this one reminds me a lot of this really old one of the earlier vector, black and white vector game coin up arcade games called lunar lander, but it was totally a physics game as well where you had to navigate your fuel and land on these little platforms

9:15on a lunar surface. I was terrible at it and it was, but it had such good sound. What's your next one for us? So our host for Circle Python Day Liz Clark built a hardware music visualizer for the fruit jam modeled on the old Atari video music box. She calls it the fruit jam video music machine. And let me see if I got a I got a picture up here. I can show you. So this is kind of what it looks like. This is just the the the white screen is just a monitor. The device that she built is this cool kind of 1970s looking thing with wood grain and these step switches and the cool brushed aluminum knob. So the original Atari video music hardware was released in 1977 and it was the first commercial video music visualizer as far as I'm aware, but it had no CPU. The video it output was created with just with logic chips clocked from the video signal and modulated by the audio signal. It looked like a piece of high five year with four knobs and 12 buttons. You would know it was like something for your for your TV.

10:16It looked like something that would just belong here in your amp stack. But with those controls, you can get a neat range of effects that reacted to music. And granted all these effects were variations of colorful diamonds or lines, kind of some of which that Liz has put up here on her on her demo. But they were still pretty neat. This is like 97. So Liz, Liz took the design inspiration from the targeting music. It made this cool, free gem based thing. And the code that she has for it is pretty cool because it takes the audio from the mic that's oh yeah, instead of having to feed a mic into it, it just reads from a built-in microphone. So it takes audio in real time. It takes audio in from the mic. It gets a spectrogram of that audio using FFT. And it does analysis on that spectrogram to use it as inputs for the various visual effects. And this kind of process, this loop is really useful for a lot of audio projects. Anytime you want to do any kind of, I'm going to look at the audio at a more kind of higher level than just looking at the amplitude.

11:18This is the same process. So if anyone is interested in doing any sort of audio project that actually does audio analysis, look at Liz's code. You can get some cool techniques from it. I love audio reactive projects. My first circuit python project ever was an audio reactive project with a PDM in mic in an 8x4, so a 32 neopixel feather wing. Still sits on my desk to this day. Oh cool. Yeah, I love audio reactive stuff. So what's your next one for the show? Where to start with this one? First, let me start this by saying I'm not a game designer. I don't know anything about designing games. So if I get some of the details wrong here, I'll just apologize up front. One of the knocks against circuit python is that it's not that fast when compared to our Dween or C, and that's okay. That wasn't a primary feature for circuit python. But that perception may be why circuit python doesn't have a lot of homebrew games for it, and that's where pico game comes in. Pico game was created by Vladimir smithka and he's created a great write up of pico game

12:19on chiptron EU. Pico game is a small 2D game engine built on top of circuit python and requires about 200k of ram to run, and it can also run on the RP 2040 and 2350 family as well as a number of boards from expressive. What smithka as he goes by and discord has created is a game engine written in C compiled into circuit python. This handles all the graphics including collisions and other computationally heavy tasks. On top of that is a set of python libraries to help with usb game pads, keyboards, audio, synthesis, animations, score saving, and more. This lets the programmer focus on what's important, the game design, and the game programming is done in circuit python and we all know that python is one of the more popular languages and circuit python tries to conform as much as possible with c python or desktop python. Smithka shares his motivation for creating pico game and that he had a pico pad that you see on the screen here, a checkmate handheld gaming device that uses an RP 2040.

13:21The pico pad has a picture of a defender like game on it and smithka tried to recreate it but found display IO too slow and so pico game was born. With pico game using a core written in C, performance goes way up and the article also shares the impressive performance stats. There's an 8 afro game called bouncing balls that runs at about 115 frames per second normally. With pico game's compatibility layer, more than double to 250 frames per second. We mentioned Dan cogley on his moon miner game earlier, smithka rewrote that in pico game and not only was it six times faster, the code was 40% smaller thanks to the engine's native functions. So what can you create and how do you create a game with pico game? Well, it's got a great documentation website and just starting at the top, it's got what is pico game. You can see it in action here, it tells you what it gives you and then right here it shows you what can you build. So not only does it have the example games in there, you can try them right in your browser.

14:24Yeah, the simulator aspect of pico game is really cool because it lets you kind of work on something wherever you're at. You don't have to have the particular piece of hardware you're designing for with you at all times. Right. And what I love about this with the games is not only can you play them right in your browser, you scroll down and you can see that this Tetris clone is running in less than 200 lines of circuit python. Oh, we're not seeing that. We're just seeing we're just seeing your browser. Oh, no. I'm not quite sure how to change that to be honest. So let me drop this in the discord. But if you hit that link, you'll go right to the playground where you can try the games in the browser and see the code that makes up each game. So the development has all been in the open. Smica has shared progress and asked for feedback in the circuit python development discord channel. And it was even a recent discussion about if I understood it right, including Pico game in the circuit python core and not as a library. I think this is an awesome idea.

15:25The battery is included in nature of having this built right into circuit python would make it a great fit. Parrot was something like the fruit jam and we'll have to get the word out to the maker and home brew game communities that there's a new game platform on the block. You want to see Pico game in action tune into foaming guys game jam screen later today at 6 p.m. Eastern. He'll be building his game and Pico game and I'm looking forward to see what he comes up with. Yeah, I think there's a there's a PR currently open in the in the in the circuit python GitHub repo, which means there is a there are pre built you have to's I think. So I think that's what happens with the PR is you get kind of pre built versions, which means you can try out Pico game in circuit python right now without having to do any sort of compiling, which is very nice. No, that's awesome. I didn't even realize that you could just install one of the you have to's off the PR. That's genius. Yeah, I think I think that's I think it's the way the way it's all set up. But yeah, it sounds like Scott's been working working with Smith to help get it into circuit python because this is like some some pretty low level changes to how the display stuff

16:26works. And so I'm really looking forward to it. Yeah, I'm excited. What's your next one for us? So another neat project outside of the the eight fruit community that I saw recently, building a autonomous Lego train with circuit python and LiDAR. This is from the from Lorraine from element 14. She also posts a nice YouTube video describing the design hurdles and how it'll come together and you can actually see the final final effect in action. But her project immediately immediately taught me two things that I should have known. Like wait, you can get a Bluetooth controlled Lego train. Like when did this happen? Oh, I'm going to have to get. Yeah, I might have to get one of those. The other is there are serial controllable 360 degree LiDAR scanner modules. They're like 70 bucks. I'll put a couple of links in the show notes for like later. If you're listening to this on a podcast, clearly I'm not as good a hacker as I thought I was that I missed these two things existed. I thought I thought LiDAR scanners like hugely expensive like multi thousand lot of things. You can only put on top of your smart car or whatever.

17:26But now you can get them and they're about the size of a you know, deck of playing cards. So her project is really funny. There's a circuit Python on a C, Jow, inner F52840 to talk BLE to the train and then talk serial to the LiDAR scanner and control Neopixels along the way. And let's see if there's a high figure of his actual picture that this is kind of the picture of the final the final result. And this is a perfect perfect use for circuit Python because you know circuit Python BLE on the inner F chips is really great and doing serial and Neopixels is so easy. The only real like complexity was the data coming off the LiDAR is just kind of this raw data that you need some some math, some algorithms to actually parse and something useful. But fortunately she found some Python code for the Raspberry Pi written in normal Python and was able to quickly port this to the circuit Python because that's one of the great things about about circuit Python is it's almost like real Python. And so if you find algorithms, there's a good chance that it'll work for it'll get the you can get his work for circuit Python.

18:27And so the result is that she's got this autonomous light up train that moves along it moves along a track along on her wall up near ceiling and it knows where it's going. So it doesn't run into the ends or or the something on the track knows to stop. Yeah, it's like yes, you know, she she she notes that you could have done this with maybe just a couple of ultrasonic distance sensors. But that's not nearly as fun as using the LiDAR scanner. Right. So this is a cool watch watch the video she she shows in the video. I don't know how the hell well this will play, but getting data off the LiDAR scanner and and because it basically gives you a sort of 360 donut around it to show you how far things are and this is her hand planer with the LiDAR scanner. And just getting the raw data out at a certain arcs of the view that it has. But it's really cool. Highly recommend checking out this this article and watching the video. Yeah, watch the video for sure. And like you mentioned, I love the fact that she was able to take Python code important

19:30to circuit Python. Like I mentioned earlier, right? Circuit Python tries to conform as much to see Python as it can. And that's just one of the benefits is that portability, which is just so cool. So sure what you're I guess maybe final one is this is a certain a real one is done. Time flies on our live. By now I'm guessing most folks have heard that our favorite circuit Python code editor Moo was sunset back in December of 2024. We've seen a couple of really strong online editors since then. And now we have a spiritual successor to Moo called RV circuit studio created by Armstrong Subaru RV circuit studio is a full featured circuit Python ID itself written in Python. It has so many nice touches. I'll probably forget a few. But the first time you start it up, it asks you, where do you want to back up your code dot pie file, which is so nice. Just pick a local directory on your PC and it will also save it there when you update your code dot pie on and then when you plug it in a board, it will detect whether it's running

20:30the latest version of circuit Python or not and open the download page to your board to help you if you're running an older version to make it easy to download. So here's a here's RV circuit studio in action. The first thing that you might want to do is hit the settings button and make the text size a little bit a little bit a little bigger than it is. It's a little small when you start and I've got it blown up for the live stream today. But everything that you need is right along in the menu bar. So you can see what you can open files here. There's a play button for the repel to start and stop. One thing to notice that control C and control D does not work down here. You actually have to use the button to start and stop your code. I've got a nice pink feather RP 2040 with a very old DPS 310. So let me do this in pink. Pink feather. That's right. Very proud of that. And this is a temperature and a barometric pressure sensor. And I've just printing the temperature in Celsius to the repel. So one of the other nice things that does is it makes Todd bots serial plaster obsolete.

21:35It has a whole serial plotter built in. And you can see it plotting along the temperature. You can see when I grabbed it and it actually changed the temperature. But here's where my favorite feature might be. In the left hand sidebar here are a ton of code snippets organized by type. I don't know about you, but I learn a lot by cobbling together different bits of code. And here it puts a ton of examples right at your fingertips. From debouncing, there's an example for that to PWM, to battery voltage monitoring, it's all built in. Like I mentioned, it's a Python app available on Windows, macOS, and Linux. But it's not a native app, so you'll need to use the built-in menu bar, like I mentioned earlier up here. Everything in the UI has a toggle, so you can hide or show the project explorer, the snippets, and more. It has a debugger built in and you can step through functions like you would find in most modern IDs. You can also reformat your code using the black lantern, and it will also prompt you to install it the first time you try to run it.

22:37And lastly, one of my favorite features is the library manager. What it does is it shows you all the libraries that you have installed in a list, and they're color-coded if the library needs to be updated, and there's just one button to click update, and it will update all your libraries for you right in the IDE, which is great. And then it's got another button right next to it called Browse the Bundle, where if you click that, you can look for any library that you need in the official bundle. I wasn't able to get the community bundle up and running within it. I'm sure I'm probably just missing something. No, it's a, I actually opened an issue on this, and it's an official response that he will not support the community bundle. Oh, bummer. Okay. Yeah, it's a bummer. Yeah. But either way, my hat's off to Armstrong. You know, thanks for creating RV Circuits Studio. When someone asked me for an editor recommendation, this is now my go-to for circuit Python. It runs locally, has install packages from macOS, Windows, and Linux. It does all the major things you would expect, and there are so many nice touches from

23:38the code backup, to the snippets, to the library manager, choosing black for code formatting. I could go on. I'm a big fan. Yeah. And it's also written in Python itself, like desktop Python. So if you want to learn, like if you're pretty good at circuit Python, and want to learn more like, quote, unquote, real Python, you can totally produce his app here and kind of see what how things work. But because I think it is written in Python, some of these other aspects we might expect from an application, like being able to do control C in the REPL, or use the native file edit view menu doesn't really exist. So just be aware. It's kind of its own little self-contained world. Yep. It sure is. What's your next one for us? This is another retro inspired project from Liz Clark. Thank you, Liz. This is the chiptune player. Let's say inside this cool little arcade looking box is a feather, an I2S audio deck, and a touchscreen display that has a SD card little holder at the top.

24:39And it lets you load up an SD card with retro chiptunes and play them. And you think, oh, that's just like an MP3 player or a wave player. But no, it's so much cooler. This is Liz made a circuit Python library that uses synthIO to emulate the AY8912 sound chip. This is a chip that's been in many coin-out video games from the 1980s. All those bleeps and bloops you might think of old video games are probably sounds generated from the AY8912. Unlike today's modern fancy game sound generation hardware, back in the 80s you had to use one of these special chips to make noise and they had very specific limitations. For the AY8912 you got three whole channels of sound and each channel could either play a square wave or white noise. And you could adjust the pitch and the volume. But that was it. If you wanted to do sort of envelope generation, there was one envelope generator for the whole chip. It went and infected all the voices. There was no filters. There was nothing. But with that, a clever game designer could make a whole video game soundtrack with game

25:43sound effects. And so some of my favorite arcade games from that time period that used this chip are Frogger, Tron, and Spy Hunter. I love Spy Hunter. So these chips are very beloved. So much so that there's a whole special file format called VGM files for video game music. This stores the various chip instructions on how to make sounds at certain times. And there's entire fan websites out there that will, let me see if I can show you real quick here. It's called VGA Rips. Here we go. So these are VGM files for various games or other things. And you can just download these and stick them on the SD card and play them in Liz's thing because her circuit Python library parses these VGM files and then runs that through the Y8912 emulator. And the library is pretty cool because it's a great demonstration of how SynthIO does stuff

26:44and how you had to use it for something actually useful. Because like, hey, doing three square waves and some noise with a simple envelope, that's something that SynthIO can totally do and being able to like have that as a, here's the thing that accomplishes a specific goal is very cool. I've been for the last like year or so trying to do an SN76489, I think a sound effects chip emulator. This is a chip that you could buy from RadioShack back in the 70s and 80s. It's about the same complexity as the, as this chip that lives emulated. So thank you Liz. I might be still in some of your work. I've got to live open source. And like you, I was a big spy hunter fan, but I think I love the Tron video game even more. Yeah, it was good. All right. Well, I think we have time for one more and Todd, I'll let you share it as it's one of the most innovative uses of circuit pipe that I've seen in the last year. Yeah. And I forgot to bring up a, bring up a screen for this. Here we go. I think maybe this has a really nice website for it.

27:45It's called Pico TTY. There's actually a really good story about this as well. So Cienic software embedded system news is a really old embedded software blog. Very handy to look at. So what is Pico TTY? Imagine this. You've got a whole cluster of servers and you need to manage them remotely. What do you do? So Pico TTY helps you manage that server cluster with a collection of Picos running circuit Python and then a Raspberry Pi 2W as a manager. It's a real niche tool for system administrators to manage groups of machines, but it shows how useful circuit Python can be even in these domain environments. The problem with servers is that they're headless. They've got no screens, no keyboards, but you still need to be able to remotely type on their keyboards and see their console messages, especially when they boot. Normally, it means this, you have to buy some expensive remote management KVM hardware. But security researcher, Chiranjeevi created a low cost system for network serial console for network serial console with keyboard injection using Raspberry Pi Picos.

28:49And they're in circuit Python using the USB serial and USB hid modules that are built in circuit Python. The circuit Python Picos feed keystrokes to the server to type commands on their keyboard because it looks like a keyboard to the server. And then it receives console messages over USB serial. This does require that the server is configured to actually output console messages via serial, which is something that Linux can do, but Windows can't do, I think. And then the reason why there's a Picos that you've got, sorry, there's one there's a Raspberry Pi 2W in there. Is it a hub? It receives all the messages from the Picos, unless you control the various Picos via a nice web interface. You can see server different server messages from all the different servers in real time. You can send keystrokes. You can even do OTA updates of the Picos if you want to update like the version of circuit Python or whatever without having to touch anything. As long as you can access the Raspberry Pi 2W, you can access all the servers and all these little Picos controlling the servers. So this is kind of the architecture diagram of what he's got set up.

29:50Here's the Raspberry Pi 2. Here's the various Picos and then these are the various servers out at the bottom here. And if you wanted to, you can even make a little 3D printed enclosure that includes four of these modules for these Picos and a Raspberry Pi. It's something that I wish I needed. I needed this like 20 years ago back when I was a system in. Don't need it now. But I've got a home lab with maybe four servers that could perhaps benefit from this, but it's so cool and it's kind of neat to see the ghost of my past job kind of pop up. What a great use of circuit Python. For so often we think of makers or maybe people new to programming are coming to circuit Python, but here it is in a commercial production environment being used with real world servers, which is just so cool to me. Yeah. Well, that's our show. Thanks for hanging out with us and to learn more about the bootloader, visit the bootloader.net or find us in your favorite podcast app. Stay tuned for JP's workshop at the top of the hour and thanks to Adafruit for having us.

30:50Until next time, stay positive.