DIY SI5351 Radio Tunes In SW, MW, And More

July 2, 2026 by 3 Comments

There are plenty of radios you can buy that pick up MW and SW bands if that’s what you’re into. Or, you can follow [mircemk]’s example, and whip one up yourself instead.

The build employs an ESP32 as the brains of the operation. It’s hooked up to a rotary encoder and a small colour TFT screen, which displays an old-school style tuning dial for choosing the desired frequency. This setup is paired with an Si5351—a capable clock generator chip that can deliver just about any frequency from <8KHz up to 150+ MHz on command. There’s naturally a bunch of supporting analog hardware for the radio end of things, plus a NE612 mixer IC and a PAM8403 class D audio amplifier board, hooked up to a small 0.25W speaker for audio output. [mircemk] has set up the rig to act as a simple radio set, or, with the flick of a switch, it can be configured for SDR use with an attached computer.

It’s a handsome build, and one that likely proves a pleasant way to browse the MW and SW bands on a rainy afternoon. We’ve looked at other hardware in this category before, too. Video after the break.

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An EInk, ESP32-based Game Boy

July 2, 2026 by 1 Comment

This is one of those projects that was both inspired and made possible by the absolute embarrassment of dev boards available to the modern hacker. In this case, the dev board was the M5Stack PaperS3, which as the name implies combines an ESP32-S3 with an e-ink panel. [Wenting Zhang] picked one up and was immediately inspired to try and make an e-ink Game Boy.

The M5Stack PaperS3 made this project possible by exposing the display with row/column control — parallel, some would call it, as opposed to the usual serial interface of SPI. That allowed [Wenting] to work some of the same e-ink magic he perfected on his Modos monitors to allow partial refresh at up to 60 Hz. That the ESP32-S3 is capable of emulating a Game Boy while driving the screen should surprise no one, since it can emulate an MSX while outputting VGA or even Windows 95 on a 386. In this case, he’s basing the actual Game Boy emulation on Crank Boy.

Of course the e-ink screen on the M5Stack is far larger and has a much higher resolution than what the Game Boy shipped with, which lets him implement touch controls and scale the image up 3X so he can fake a couple of shades of grayscale while actually outputting black and white. Even better, if he was actually playing this thing on the regular, once the high-refresh portion of the screen starts to wear out, he can flip the orientation and keep gaming on the virtually-unrefreshed control portion of the screen — doubling the lifetime of the system, something many of you raised as a concern when we last looked at a his e-ink monitor project.

The only real shortcoming of this hack is the sound. With one-bit beeps coming out of the M5Stack buzzer, it’s got nothing on Nintendo’s hardware. Of course, that’s partially down to using the hardware as-is. With the addition of an I2S sound chip like the one used in the MOD player project we featured recently, you’d just need to squeeze out enough processor cycles to make this sound as good as it looks.

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FLOSS Weekly Episode 873: Wait, That’s Not Open Source!

July 1, 2026 by 2 Comments

This week Jonathan chats with Andy Gryc and Aaron Basset about QNX, and the interesting Open Source history and future of that embedded OS. Why does QNX Everywhere feel more open, and why do you need to register an account to download images? All that and more — Watch to find out!

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A grey box surrounding a circular red component is mounted on an aluminium extrusion frame. The circular red face has a protrusion extending from it with a white ball bearing at the tip.

Building A Micrometer-Level Displacement Sensor With 3D Printed Parts

June 30, 2026 by 7 Comments

Every experienced machinist knows the value of taking regular measurements. If one works carefully and checks dimensions frequently, it’s possible to make a part much more precise than could be made by relying on the machine’s accuracy alone. In a similar vein, it’s possible to make a measuring device out of comparatively crude parts, as long as their behavior is well understood. Related to both principles is [BubsBuilds]’s displacement sensor, which uses a 3D printed frame but reaches precision better than two micrometers.

Admittedly the printed parts aren’t the source of the sensor’s precision, that comes from an opto-interrupter. This design has a central stylus, one end of which contacts the object under measurement. The other end flattens to a knife-edge blade, which fits between the diodes of the opto-interrupter. As the stylus point is pressed in, the blade blocks off more light from reaching the photodiode, creating an output signal proportional to displacement. To keep the stylus from twisting or moving side-to-side, two flat, circular flexures hold the stylus in the center of a cylindrical housing.

[Bubs] printed several flexure variations to see how well they resisted and permitted various torques and forces, and a symmetrical flexure design proved best for his purposes. Once the sensor was assembled, he tested it against the measurements recorded by a laser confocal displacement sensor. This design was an update from a previous version, and it improved in a few regards: the non-linearity had decreased, and the repeatability was now better than two microns, though the range had been halved. Significantly, though, it’s now much easier to mount, making this an actually practical tool.

If, however, this doesn’t fit your needs, there are many other ways to build a linear displacement sensor, ranging from capacitive to magnetostrictive. On the manual side of things, we’ve also covered a comparison of calipers.

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The Teenage Angst Of 3D Printing: Solidoodle, Printrbot, And Bridges

June 29, 2026 by 36 Comments

Bridges are a part of our constructed landscape that we take for granted. And bridges by themselves aren’t especially important. What is important is that bridges let you get from one place to another. Technology is often the same. We get from point A to point B through some bridge technology that, probably, most normal people never even notice.

Years ago, point A was commercial 3D printing. Industry had stereolithography, selective laser sintering, fused deposition modeling, and other rapid-prototyping technologies. These were not toys. They were expensive industrial systems used by companies that needed prototypes badly enough to pay serious money for them.

Fast Forward to Today

Today, you can go to a big box store and buy a 3D printer for well under $1,000, and often far less. Modern machines are almost plug-and-play and tend to do all the hard parts for you. That’s point B. How we got between points is a story of hackers who had a dream, and many Hackaday readers lived through it and even played a part in that bridging.

For a long time, RepRap was synonymous with hobby-level 3D printing. The project, started by [Adrian Bowyer] at the University of Bath in 2005, was built around a powerful idea: a machine that could print many of its own parts, thereby helping make more machines. RepRap Darwin reached its early self-replicating milestones in 2008, and the movement produced a thicket of descendants, variants, and arguments about rods, belts, bearings, extruders, firmware, and what “self-replicating” really meant. Of course, the machine could only print some of the parts you needed, but it was still impressive how much of a printer you could make with one printer.

Without RepRap, the desktop 3D printer boom would have looked very different. It created a common pool of ideas: Cartesian frames, printed brackets, hobbed bolts, heated beds, RAMPS boards, Marlin firmware, and a whole common vocabulary. It also created the expectation that a 3D printer was something you could understand, modify, repair, and improve. That expectation would not survive everywhere, but it defined the early culture.

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Accurate Split-Flap Display Can Be 3D Printed

June 28, 2026 by 11 Comments

Split-flap displays are a great, low-power way to display text to a wide audience. Compared to other display technologies like LCDs they only use energy when the characters change, but have fallen out of favor partially because of their greater mechanical complexity and also because LCD and LED technology has become so inexpensive. They still retain a loyal following though, and [Jason] is demonstrating his version which boasts high accuracy and can be 3D printed.

To get good results, one of the keys is getting the motor positioning just right. The motor sits in the center and spins the flaps around, so stopping at exactly the right point to display a certain character is critical. [Jason]’s system uses a 28BYJ stepper motor with a magnetic encoder to ensure that the correct flap is displayed. The flaps themselves are completely 3D printed, using a method which allows for two colors to be printed even if the printer is only designed for a single color. Once printed, the flaps are installed on the wheel which is the outer ring of a planetary gear set with the stepper motor sitting in the middle.

Each character in the display is housed in a printed enclosure, and for [Jason]’s project he only needs five characters, so to control the entire setup he’s using a Raspberry Pi Pico. For more characters he suggests that it is still possible to use a smaller microcontroller like the Pico but a multiplexer may be needed. Of course, displays like this are not limited to characters alone. Take a look at this display which has custom flaps to display the current weather conditions as well.

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A man standing next to an RC model of an Airbus A380 aircraft. The fuselage is at elbow height and the tailfin appears to be over his head.

World’s Biggest RC A380 Is A Big Deal

June 27, 2026 by 15 Comments

RC planes are a lot of fun, and the bigger the better! [Ramy RC] has built the world’s biggest RC A380.

At 29 ft (8.83 m) long, with a 32 foot (9.75 m) wingspan, and weighing 800 lb (362 kg), this 1/8 scale jumbo jet is not your typical model. The fuselage is built from CNC cut EPS foam layed up with fiberglass on the outside and carbon fiber inside. The wings have a combination of carbon, aluminum, foam, and wood components to handle the aerodynamic loads.

The attention to detail is wild. Instead of painting the windows, each one is an actual hole in the plane with a 3D printed window frame and acrylic window. You can actually see one falling out of the plane in the video below. An Airbus mechanic in the comments even notes the landing gear door order of operations are identical to the real thing.

If [Ramy] looks familiar, perhaps you remember his previous A380 build? Much like the 747, the full size A380 is no longer in production, but they can run on cooking oil while they’re still flying.

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