pi pico

60 Articles

BreadboardOS, A Command Line Interface For The Pico

May 14, 2024 by 25 Comments

Operating systems! They’re everywhere these days, from your smart TV to your smartphone. And even in your microcontrollers! Enter BreadboardOS for the Raspberry Pi Pico.

BreadboardOS is built on top of FreeRTOS. It’s aim is to enable quick prototyping with the Pi Pico. Don’t confuse operating system with a graphical environment — BreadboardOS is command-line based. You’d typically interface with it via a serial terminal emulator, but joy of joys, it does support color!

Using BreadboardOS is a little different than typical microcontroller development. Creating an application involves adding a “service” which is basically a task in FreeRTOS parlance. The OS handles running your service for you. Via the text interface, you can query running services, and start or kill them at will.

Meanwhile, running df will happily give you stats on the flash usage of the Pi Pico, and free will tell you how full the memory is doing. If you really want to get raw, you can make calls to control GPIO pins, the SPI hardware, or other peripherals, and do it right on the command line.

BreadboardOS isn’t for everyone, but it could prove a useful tool if you like that way of doing things. It’s not the only OS out there for the Pi Pico, either!

Continue reading “BreadboardOS, A Command Line Interface For The Pico” →

This Tiny Game Boy Lets The Real Thing Play Online

May 13, 2024 by 5 Comments

Back in 2021, [stacksmashing] found that it took little more than a Raspberry Pi Pico and some level-shifters to create a USB connection with the Game Boy’s link port. Add in the proper software, and suddenly you’ve got online multiplayer for the classic handheld. The hardware was cheap, the software open source, and a good time was had by all.

Inspired by both the original project and some of the hardware variations that have popped up over the years, [weiman] recently set out to create a new version of the USB link adapter that fits inside a miniature 3D printed Game Boy.

The big change from the original design is that this is using the far smaller, but equally capable, RP2040-Zero development board. This is mated with a SparkFun logic level converter board (or a clone of one from AliExpress) by way of a custom PCB that also includes the necessary edge connectors to connect directly to a Game Boy Link Cable.

Once the PCB is assembled, it’s dropped into the 3D printed Game Boy shell. [weiman] really worked some nice details into the case, such as aligning the d-pad and buttons in such a way that pressing them engages either the RESET or BOOTSEL buttons on RP2040-Zero. The screen of the printed handheld also lines up with the RGB LED on the top of the dev board, which can produce some cool lighting effects.

The original project from [stacksmashing] was an excellent example of the capabilities of the Pi Pico, and we’re glad to see it’s still being worked on and remixed by others. Even though the state of Game Boy emulation is nearly perfect these days, there’s still something to be said for working with the original hardware like this.

Pi Pico Gets A ZX Spectrum Emulator

April 27, 2024 by 9 Comments

The Pi Pico is a capable microcontroller that can do all kinds of fun and/or useful things. In the former vein, [antirez] has ported a ZX Spectrum emulator to the Pi Pico.

ZX2040, as it is known, is a port of [Andre Weissflog’s] existing ZX spectrum emulator. It’s designed for use on the compact embedded Pi Pico platform, using ST77xx TFT displays. To that end, it has a UI optimized for small, low resolution screens and minimal buttons. After all, very few Pi Picos come with a full QWERTY keyboard attached.

Certain hacks are necessary to make it all work; the chip is overclocked to get things humming fast enough. The emulator also runs upscaling or downscaling in realtime as needed. This allows the emulator to run with a variety of displays, almost none of which are a direct match for the ZX Spectrum’s original resolution of 256×192 pixels.

Code is on Github for the curious, including a great run down from [antirez] on everything that makes it tick. If you want to play ZX Spectrum games on a keychain, you’d do well to start here. There are other projects to emulate it on the Pico, too! Video after the break.

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Building A Giant Boardgame Isn’t Easy

April 19, 2024 by 8 Comments

[Stevenson Streeper] is a maker, and was recently charged with a serious mission. He had to prototype, design, and build a board game. A software-controlled board game, that is, and one that was 400 square-feet in size. As you might imagine, this ended up being a tall order, and he’s been kind enough to share his tale on his blog.

His client’s idea was for a giant interactive game board akin to the glowing disco floors of old. It had to play a game approximating the rules of “The Floor Is Lava.” It had to handle up to 20 players at a time, too.

[Stevenson] runs a company that delivers “Activations”—basically big showpieces for customers willing to pay. This wasn’t his first attempt at building an immersive attraction, but it was a big job, and a challenging one at that. He explains the difficulties that came about from a limited crew, limited timeline, and a number of difficult missteps. Hurdles included surprise unusable off-the-shelf hardware and the difficulty of hand-sanding 144 tiles of polycarbonate. One weeps for the project’s plight early on – if only the AliExpress tiles were documented.

He may have bitten off more than he could chew, and yet—the project was finished and to a decent degree of functionality success. That’s to be applauded, and [Stevenson] learned a ton along the way. Big projects can be daunting and can put you in a bind. As this story demonstrates, though, perseverance often gets you somewhere okay in the end. Video after the break.

Continue reading “Building A Giant Boardgame Isn’t Easy” →

PicoNtrol Brings Modern Controllers To Atari 2600

April 13, 2024 by 11 Comments

While there’s an argument to be made that retro games should be experienced with whatever input device they were designed around, there’s no debating that modern game controllers are a lot more ergonomic and enjoyable to use than some of those early 8-bit entries.

Now, thanks to the PicoNtrol project from [Reogen], you can use the latest Xbox and PlayStation controllers with the Atari 2600 via Bluetooth. Looking a bit farther down the road the project is aiming to support the Nintendo Entertainment System, and there’s work being done to bring the Switch Pro Controller into the fold as well.

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The board in question, with a Pi Pico soldered on, with old PCBs for macropads being used as captouch electrodes

Give Your Pi Pico Captouch Inputs For All Your Music Needs

March 31, 2024 by 11 Comments

Unlike many modern microcontrollers, RP2040 doesn’t come with a native capacitive touch peripheral. This doesn’t mean you can’t do it – the usual software-driven way works wonderfully, and only requires an external pullup resistor! In case you wanted a demonstration or you have a capacitive touch project in mind, this lighthearted video by [Jeremy Cook] is a must watch, and he’s got a healthy amount of resources for you in store, too!

In this video, [Jeremy] presents you with a KiCad schematic and an PCB design you can use to quickly add whole 23 capacitive touch sensing inputs to a Pi Pico! The board is flexible mechanically, easy to assemble as [Jeremy] demonstrates, and all the pins involved can still be used as regular GPIOs if you’d like. Plus, it’s fully open-source, can easily be assembled on your own, and available on Tindie too!

Of course, such a board doesn’t get created for no reason – [Jeremy] has a healthy amount of musical creations and nifty ideas to show off. We quite liked the trick of using old PCBs as capacitive touch sensing, using copper fills as electrodes – which has helped create an amusing “macropad of macropads”, and, there’s quite a bit more to see.

If capacitive touch projects ever struck a chord with you and you enjoy music-related hacking, [Jeremy]’s got a whole YouTube channel you ought to check out. Oh, and if one of the musical projects in the video caught your eye, it might just be the one we’ve featured previously! Continue reading “Give Your Pi Pico Captouch Inputs For All Your Music Needs” →

Playing Audio On The Pi Pico With No DAC To Speak Of

March 12, 2024 by 24 Comments

Normally, if you want to play music or other audio on a microcontroller, you need to get yourself a DAC. Or at least, that’s the easiest way to go about it and the one most likely to get you good, intelligible audio. You don’t have to go that way, though, as [antirez] demonstrates.

[antirez] decided to do this with a Pi Pico, but it’s applicable to other microcontrollers too. It’s all done with a single pin and a PWM output. The PWM output is set to a very high frequency beyond human hearing. In this case, it was 100 KHz. Then, the duty cycle of the PWM is changed to essentially output various average voltage levels at the pin. Vary the output voltage as per your desired sound file by using each sample to vary the duty cycle of the PWM. Voila! You can output whatever sound you want on that pin! [antirez] steps through the basics of doing this, including processing simple WAV files into a raw format that can be dumped into MicroPython code.

There’s no sound sample on the project page, and we’d have to assume it sounds pretty crunchy when hooked up to a speaker. And yet, it could prove a useful technique if you’re designing your own audio greeting cards or something, so keep that in mind!