rp2040

142 Articles

Pico-mac-nano Fits Working Macintosh On Barbie’s Desk

May 26, 2025 by 13 Comments

Have you ever looked in a doll house and said “I wish those dolls had a scale replica of a 1984 Macintosh 128K that could be operated by USB?” — well, us neither, but [Nick Gallard] gives us the option with his 63mm tall Pico-mac-nano project.

As you might imagine, this project got its start with the RP2040-based Pico Mac project by [Matt Evans], which we covered

The collector’s edition will come with a lovely box, but it’s still open source so you can make your own.

before. [Nick] saw that, built it, and was delighted by it enough to think that if the Mac could run on such tiny hardware, how small could build a fully-usable replica Mac? The answer was 63 mm tall– at 5.5:1, that’s technically under the 6:1 scale that Barbie operates on, but if we had such a dollhouse we’d absolutely put one of these in it. (You just know Barbie’s an Apple kind of girl.)

The size was driven by the screen, which is a 2″ TFT panel with 480 x 640 pixel native resolution. Here [Nick] cheats a tiny bit– rather than trying to rewrite the PicoMac to output 640 x 480 and rotate the screen, he keeps the screen in portrait mode and drives it at 480 x 342 px. Sure, it’s not a pixel-perfect output, but no LCD is going to be a perfect stand in for a CRT, and who is going to notice 32 pixels on a 2″ screen? Regardless, that set the height of the computer, which is built around the portrait display. A highly detailed, and to our eyes, accurate replica of the original Macintosh case was printed to fit the LCD, coming in at the aforementioned 63mm tall.

Unfortunately this means the floppy drive could not be used for micro SD access– there is an SD card reader on this unit, but it’s on the back, along with a USB-C port, which is roughly where the mouse and keyboard ports are supposed to be, which is a lovely detail. Also delightful is the choice of a CR2 lithium battery for power, which is a form factor that will look just a bit familiar if you’ve been inside one of these old Macs.

[Nick] has posted the 3D designs and modified pico mac firmware to a GitHub repository, but if you’re looking for a charming desk ornament and don’t have the time to build your own, he will also be selling these (both kits and fully assembled units) via 1bitrainbow, which is the most delightfully retro web store we’ve seen of late.

If Classic MacOS isn’t good enough for you, how about linux? You won’t enjoy it as much, but it will run on the RP2040.

The ZX Spectrum Logic Analyzer

May 12, 2025 by 8 Comments

We know [Happy Little Diodes] frequently works with logic analyzer projects. His recent wireless logic analyzer for the ZX Spectrum is one of the oddest ones we’ve seen in a while. The heart of the system is an RP2040, and there are two boards. One board interfaces with the computer, and another hosts the controller.

The logic analyzer core is powered by a common open-source analyzer from [Eldrgusman]. This is one of the nice things about open source tools. Most people probably don’t need a logic analyzer that plugs directly into a ZX Spectrum. But if you do, it is fairly simple to repurpose a more generic piece of code and rework the hardware, if necessary.

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Read Motor Speed Better By Making The RP2040 PIO Do It

April 29, 2025 by 8 Comments

A quadrature encoder provides a way to let hardware read movement (and direction) of a shaft, and they can be simple, effective, and inexpensive devices. But [Paulo Marques] observed that when it comes to reading motor speeds with them, what works best at high speeds doesn’t work at low speeds, and vice versa. His solution? PicoEncoder is a library providing a lightweight and robust method of using the Programmable I/O (PIO) hardware on the RP2040 to get better results, even (or especially) from cheap encoders, and do it efficiently. Continue reading “Read Motor Speed Better By Making The RP2040 PIO Do It” →

RP2040 Spins Right ‘Round Inside POV Display

April 25, 2025 by 3 Comments

Sometimes, a flat display just won’t cut it. If you’re looking for something a little rounder, perhaps your vision could persist in in looking at [lhm0]’s rotating LED sphere RP2040 POV display.

As you might have guessed from that title, this persistence-of-vision display uses an RP2040 microcontroller as its beating (or spinning, rather) heart. An optional ESP01 provides a web interface for control. Since the whole assembly is rotating at high RPM, rather than slot in dev boards (like Pi Pico) as is often seen, [lhm0] has made custom PCBs to hold the actual SMD chips. Power is wireless, because who wants to deal with slip rings when they do not have to?

The LED-bending jig is a neat hack-within-a-hack.

[lhm0] has also bucked the current trend for individually-addressable LEDs, opting instead to address individual through-hole RGB LEDs via a 24-bit shift-register. Through the clever use of interlacing, those 64 LEDs produce a 128 line display. [lhm0] designed and printed an LED-bending jig to aid mounting the through-hole LEDs to the board at a perfect 90 degree angle.

What really takes this project the extra mile is that [lhm0] has also produced a custom binary video/image format for his display, .rs64, to encode images and video at the 128×256 format his sphere displays. That’s on github,while a seperate library hosts the firmware and KiCad files for the display itself.

This is hardly the first POV display we’ve highlighted, though admittedly it isn’t the cheapest one. There are even other spherical displays, but none of them seem to have gone to the trouble of creating a file format.

If you want to see it in action and watch construction, the video is embedded below.

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Writing An OLED Display Driver In MicroZig

March 8, 2025 by 18 Comments

Although most people would use C, C++ or MicroPython for programming microcontrollers, there are a few more obscure options out there as well, with MicroZig being one of them. Recently [Andrew Conlin] wrote about how to use MicroZig with the Raspberry Pi RP2040 MCU, showing the process of writing an SSD1306 OLED display driver and running it. Although MicroZig has since published a built-in version, the blog post gives a good impression of what developing with MicroZig is like.

Zig is a programming language which seeks to improve on the C language, adding memory safety, safe pointers (via option types), while keeping as much as possible of what makes C so useful for low-level development intact. The MicroZig project customizes Zig for use in embedded projects,  targeting platforms including the Raspberry Pi MCUs and STM32.  During [Andrew]’s usage of MicroZig it was less the language or supplied tooling that tripped him up, and more just the convoluted initialization of the SSD1306 controller, which is probably a good sign. The resulting project code can be found on his GitHub page.

Interposer Helps GPS Receiver Overcome Its Age

March 4, 2025 by 5 Comments

We return to [Tom Verbeure] hacking on Symmetricom GPS receivers. This time, the problem’s more complicated, but the solution remains the same – hardware hacking. If you recall, the previous frontier was active antenna voltage compatibility – now, it’s rollover. See, the GPS receiver chip has its internal rollover date set to 18th of September 2022. We’ve passed this date a while back, but the receiver’s firmware isn’t new enough to know how to handle this. What to do? Build an interposer, of course.

You can bring the module up to date by sending some extra init commands to the GPS chipset during bootup, and, firmware hacking just wasn’t the route. An RP2040 board, a custom PCB, a few semi-bespoke connectors, and a few zero-ohm resistors was all it took to make this work. From there, a MITM firmware wakes up, sends the extra commands during power-on, and passes all the other traffic right through – the system suspects nothing.

Everything is open-source, as we could expect. The problem’s been solved, and, as a bonus, this implant gives a workaround path for any future bugs we might encounter as far as GPS chipset-to-receiver comms are concerned. Now, the revived S200 serves [Tom] in his hacking journeys, and we’re reminded that interposers remain a viable way to work around firmware bugs. Also, if the firmware (or the CPU) is way too old to work with, an interposer is a great first step to removing it out of the equation completely.

The Perfect Pi Pico Portable Computer

February 22, 2025 by 25 Comments

[Abe] wanted the perfect portable computer. He has a DevTerm, but it didn’t quite fit his needs. This is Hackaday after all, so he loaded up his favorite CAD software and started designing. The obvious choice here would be a Raspberry Pi. But [Abe] didn’t want to drop in a Linux computer — he was going for something a bit smaller.

An RP2040 Pico would be a perfect fit. Driving a display with the Pico can be eat a lot of resources though. The solution was a PicoVision from Pimoroni. PicoVision uses two RP2040 chips. One drives an HDMI port, while the other is free to run application software. This meant a standard HDMI screen could be used.

The keyboard was a bit harder. After a lot of searching, [Abe] found an IR remote designed for smart TVs. The QWERTY keyboard was the perfect size but didn’t have an interface he could use. He fixed that with an adapter PCB including an I2C GPIO expander chip. A bit of I2C driver software later, and he had a working input keyboard.

Hardware doesn’t do anything without software though. The software running on the handheld is called Slime OS, and the source is available at [Abe’s] GitHub. It’s a launcher, with support for applications written in python. [Abe] has a few basic demos working, but he’s looking for help to get more features up and running.

Although it wasn’t quite what [Abe] was after, our own [Donald Papp] came away fairly impressed when he gave the DevTerm a test drive back in 2022. Something to consider if you’re looking for a Linux handheld and not quite ready to build one yourself.

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