When Wireless MIDI Has Latency, A Hardwired Solution Saves The Day

June 7, 2025 by 14 Comments

[Moby Pixel] wanted to build a fun MIDI controller. In the end, he didn’t build it just once, but twice—with the aim of finding out which microcontroller was most fit for this musical purpose. Pitted against each other? The ESP32 and Raspberry Pi Pico.

The MIDI controller itself is quite fetching. It’s built with a 4 x 4 array of arcade buttons to act as triggers for MIDI notes or events. They’re assembled in a nice wooden case with a lovely graphic wrap on it. The buttons themselves are wired to a microcontroller, which is then responsible for sending MIDI data to other devices.

At this point, the project diverges. Originally, [Moby Pixel] set the device up to work with an ESP32 using wireless MIDI over Bluetooth. However, he soon found a problem. Musical performance is all about timing, and the ESP32 setup was struggling with intermittent latency spikes that would ruin the performance. Enter the Raspberry Pi Pico using MIDI over USB. The hardwired solution eliminated the latency problems and made the controller far more satisfying to use.

There may be solutions to the latency issue with the wireless ESP32 setup, be they in code, hardware configuration, or otherwise. But if you want to play with the most accuracy and the minimum fuss, you’ll probably prefer the hardwired setup.

Latency is a vibe killer in music as we’ve explored previously.

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Printed Focus Control For Pro Style Cinematography

June 7, 2025 by 14 Comments

When you watch a movie and see those perfect focus switches or zooms, the chances are you’re not seeing the result of the cameraman or focus operator manually moving the lens controls. Instead, they will have been planned and programmed in advance and executed by a motor. If you take a close look at many lenses you’ll see a ring that’s more than just extra knurling, it’s a gear wheel for this purpose. Want to experiment with this technique without buying professional grade accessories? [l0u0k0e] has you covered with a 3D printable focus zoom motor accessory.

The motor behind it all is a geared stepper motor, and there are a set of printed parts to complete the model. It’s recommended to use PETG, and nylon for the gears, but it would work in PLA with a shorter life. It’s designed to work with the standard 15 mm tube you’ll find on many camera rigs, and while you can write your own Arduino sketches to control it if you wish, we’re given instructions for hooking it up to existing focus drivers. The model is on Printables, should you wish to try.

This is by no means the first focus puller we’ve seen, in fact you can even use LEGO.

3D Pen Used To Build Cleaning Robot That Picks Up Socks

June 6, 2025 by 11 Comments

Your average 3D printer is just a nozzle shooting out hot  plastic while being moved around by a precise robotic mechanism. There’s nothing stopping you replacing the robot and moving around the plastic-squirting nozzle yourself. That’s precisely what [3D Sanago] did to produce this cute little robot.

The beginning of the video sets the tone. “First we create the base that will become the robot vacuum’s body,” explains [3D Sanago]. “I quickly and precisely make a 15 x 15 cm square almost as if I were a 3D printer.” It’s tedious and tiring to move the 3D printing pen through the motions to build simple parts, but that’s the whole gimmick here. What’s wild is how good the results are. With the right post-processing techniques using an iron, [3D Sanago] is able to produce quite attractive plastic parts that almost justify the huge time investment.

The robot itself works in a fairly straightforward fashion. It’s got four gear motors driving four omniwheels, which let it pan around in all directions with ease. They’re under command of an Arduino Uno paired with a multi-channel motor driver board. The robot also has a servo-controlled arm for moving small objects. The robot lacks autonomy. Instead, [3D Sanago] gave it a wireless module so it could be commanded with a PS4 controller. Despite being referred to as a “robot vacuum,” it’s more of a general “cleaning robot” since it only has an arm to move objects, with no actual vacuum hardware. It’s prime use? Picking up socks.

We’ve seen [3D Sanago]’s fine work before, too. Video after the break.

Continue reading “3D Pen Used To Build Cleaning Robot That Picks Up Socks” →

The Bellmac-32 CPU — What?

June 6, 2025 by 34 Comments

If you have never heard of the Bellmac-32, you aren’t alone. But it is a good bet that most, if not all, of the CPUs in your devices today use technology pioneered by this early 32-bit CPU. The chip was honored with the IEEE Milestone award, and [Willie Jones] explains why in a recent post in Spectrum.

The chip dates from the late 1970s. AT&T’s Bell Labs had a virtual monopoly on phones in the United States, but that was changing, and the government was pressing for divestiture. However, regulators finally allowed Bell to enter the computing market. There was only one problem: everyone else had a huge head start.

There was only one thing to do. There was no point in trying to catch the leaders. Bell decided to leap ahead of the pack. In a time when 8-bit processors were the norm and there were nascent 16-bit processors, they produced a 32-bit processor that ran at a — for the time — snappy 2 MHz.

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A man’s hands are shown in the foreground holding two splines, each with teeth both on the interior and exterior surfaces. Both are identical in shape, but one is larger and made of plastic, and the other is smaller and made of metal.

Freeze-drying For Improved Metal Printing

June 6, 2025 by 12 Comments

For all the remarkable improvements we’ve seen in desktop 3D printers, metal printers have tended to stay out of reach for hackers, mostly because they usually rely on precise and expensive laser systems. This makes it all the more refreshing to see [Dan Gelbart]’s demonstration of Rapidia’s cast-to-sinter method, which goes from SLA prints to ceramic or metal models.

The process began by printing the model in resin, scaled up by 19% to account for shrinkage. [Dan] then used the resin print to make a mold out of silicone rubber, after first painting the model to keep chemicals from the resin from inhibiting the silicone’s polymerization. Once the silicone had set, he cut the original model out of the mold and prepared the mold for pouring. He made a slurry out of metal powder and a water-based binder and poured this into the mold, then froze the mold and its contents at -40 ℃. The resulting mixture of metal powder and ice forms a composite much stronger than pure ice, from which [Dan] was able to forcefully peel back the silicone mold without damaging the part. Next, the still-frozen part was freeze-dried for twenty hours, then finally treated in a vacuum sintering oven for twelve hours to make the final part. The video below the break shows the process. Continue reading “Freeze-drying For Improved Metal Printing” →

A woman in a richly-colored blue head scarf leans over a wooden table looking at the timer between her hands. The timer has a yellow circle on black flip panels on the left and black and white CT scans of a human torso on the right side. The frame is wood, and there is an electric motor on the upper right of the frame and a silver drum on the left of the frame beneath the woman's hand.

A Flip Clock Becomes A Flip Timer

June 6, 2025 by 2 Comments

Sometimes it’s nice to have a widget to do a single task and avoid getting distracted by the supposed simplicity of doing it with an app on a smartphone. [Dina Amin] built a timer from an old flip clock to stay focused.

Starting with a disassembly of the flip clocks she found at a flea market with [Simone Giertz], [Amin] decided to change the twenty four hour mechanism to a twenty four minute one which was similar to the amount of time she was already using for several different practices. Since she’s an expert in animation, she planned on turning a set of CT scans into the animation that would play on the section that had previously been the minutes of the clock.

As much of the original clock’s components were damaged, and [Amin] didn’t have a chance to learn clockmaking from scratch in a week, she tried a few different drive mechanisms for the build. The drum from an air fryer timer driven with an electric motor fit the bill, but off enough from proper minutes that [Amin] switched from numerals to a yellow circle that fills in as it approaches the satisfying ding of completion.

If you want to see Simone’s Moon flip clock we’ve covered that project too.

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A Network Status Panel The Way It Should Be

June 6, 2025 by 16 Comments

Sometimes a project forms itself around a component rather than an idea, and thus it was that [Maximilien] found himself building a data rate monitor for the connection between two data centers. Some MD0657C2-R LED dot matrix displays for not a lot needed a project.

The displays are mounted in groups of four on small PCBs, driven by a MAX6952, which are then controlled by a Pi Pico. There are several display panels in the project, each of which is a pained and laser-etched acrylic sheet with a pair of the LED boards mounted behind it. These in turn go on the front of a wooden enclosure, with a set of LED ring lights behind to illuminate the etched parts of the panels. Each display panel has its own Pico, daisy chained together and driven by a Pico W that supplies network connectivity.

As you might expect, this isn’t the first status panel we’ve brought you over the years.