Tulip Is A Micropython Synth Workstation, In An ESP32

We’re not sure exactly what Tulip is, because it’s so many things all at once. It’s a music-making environment that’s programmable in Python, runs on your big computer or on an ESP32-S3, and comes complete with some nice sounding synth engines, a sequencer, and a drum machine all built in. It’s like your dream late-1980s synthesizer workstation, but running on a dev board that you can get for a song.

And because Tulip is made of open-source software and hardware, you can extend the heck out of it. For instance, as demonstrated in this video by [Floyd Steinberg], you can turn it into a fully contained portable device by adding a touchscreen. That incarnation is available from Makerfabs, and it’s a bargain, especially considering that the developer [Brian Whitman] gets some of the proceeds. Or, because it’s written in portable Python, you can run it on your desktop computer for free.

The most interesting part of Tulip for us, as programmer-musicians, is that it boots up into a Micrypython REPL. This is a synth workstation with a command-line prompt as its primary interface. It has an always-running main loop, and you make music by writing functions that register as callbacks with the main loop. If you were fast, you could probably live-code up something pretty interesting. Or maybe it wants to be extended into a physical musical instrument by taking in triggers from the ESP32’s GPIOs? Oh, and did we mention it sends MIDI out just as happily as it takes it in? What can’t Tulip do?

We’ve seen some pretty neat minimalist music-making devices lately, but in a sense Tulip takes the cake: it’s essentially almost entirely software. The various hardware incarnations are just possibilities, and because it’s all open and extremely portable, you can freely choose among them. We really like the design and sound of the AMY software synthesizer engine that powers the Tulip, and we’re sure that more synthesizer models will be written for it. This is a music project that you want to keep your eyes on in the future.

Marimbatron: A Digital Marimba Prototyping Project

The Marimbatron is [Leo Kuipers] ‘s final project as part of the Fab Academy program supervised by [Prof. Neil Gershenfeld] of MIT’s Center for Bits and Atoms. The course aims to teach students how to leverage all the fab lab skills to create unique prototypes using the materials at hand.

The final polyurethane/PET/Flex PCB stack-up for the sensor pad

Fortunately, one of the main topics covered in the course is documentation, and [Leo] has provided ample material for review. The marimba consists of a horizontal series of wooden bars, each mounted over a metal resonator tube. It is played similarly to the xylophone, with a piano-type note arrangement, covering about five octaves but with a lower range than the xylophone. [Leo] converted this piano-type layout into a more logical grid arrangement. The individual pads are 3D printed in PETG and attached to a DIY piezoresistive pressure sensor made from a graphite-sprayed PET sheet laid upon a DIY flexible PCB. A central addressable LED was also included for indication purposes. The base layer is made of cast polyurethane, formed inside a 3D-printed rigid mould. This absorbs impact and prevents crosstalk to nearby sensors. The sensor PCB was initially prototyped by adhering a layer of copper tape to a layer of Kapton tape and cutting it out using a desktop vinyl cutter. While this method worked for the proof of concept, [Leo] ultimately outsourced the final version to a PCB manufacturer. The description of prototyping the sensor and dealing with over-moulding was particularly fascinating.

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Long-Awaited SLS4All 3D Printer Now Shipping

We touched on the open source SLS4All DIY SLS 3D printer a year or two ago when the project was in the early stages. Finally, version one is complete, with a parts kit ready to ship and all design data ready for download if a DIY build or derivative is your style. As some already mentioned, this is not going to be cheap: with the full parts kit running at an eye-watering $7K before tax. But it’s possible to build or source almost all of it a bit at a time for those on a budget.

Try printing THIS benchy on an FDM machine!

It’s important to note that to access the detailed information, you’ll need to create an account, which is a bit inconvenient for an open source design. However, all the essential components seem to be available, so it’s forgivable. In terms of electronics, there are two custom PCBs: the GATE1 (GAlvo and Temperature Control) and the ZERO1 (Zero-crossing dimming) controller. Other than that, all the electronics seem to be standard off-the-shelf components. Both of these PCBs are designed using EasyEDA.

Unfortunately we couldn’t find access to the PCB Gerbers, nor does there appear to be a link to their respective EasyEDA projects, just the reference schematics. This is a bit of a drawback, but it’s something that could easily be reproduced with enough motivation. Control is courtesy of a Radxa Rock Pi, as there were ‘problems’ with a Raspberry Pi. This is paired with a 7-inch touchscreen to complete the UI. This is running a highly modified version of the Klipper together with their own control software, which is still undergoing testing before release.

The laser head is built around a 10 W 450 nm laser module from China and a high-end galvanometer set. Two 200 W halogen tube heaters heat the print bed, and 200 W silicone heating pads heat both the powder bed and the print bed.

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The Dyke Delta: A DIY Flying Wing Fits Four

The world of experimental self-built aircraft is full of oddities, but perhaps the most eye-catching of all is the JD-2 “Dyke Delta” designed and built by [John Dyke] in the 1960s. Built to copy some of the 1950’s era innovations in delta-style jet aircraft, the plane is essentially a flying wing that seats four.

And it’s not just all good looks: people who have flown them say they’re very gentle, they get exceptional gas mileage, and the light wing-loading means that they can land at a mellow 55 miles per hour (88 kph). And did we mention the wings fold up so you can store it in your garage?

Want to build your own? [John] still sells the plans. But don’t jump into this without testing the water first — the frame is entirely hand-welded and he estimates it takes between 4,000 and 5,000 hours to build. It’s a labor of love. Still, the design is time-tested, and over 50 of the planes have been built from the blueprints. Just be sure to adhere to the specs carefully!

It’s really fun to see how far people can push aerodynamics, and how innovative the experimental airplane scene really is. The JD-2 was (and probably still is!) certainly ahead of its time, and if we all end up in flying wings in the future, maybe this plane won’t look so oddball after all.

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Homebrew Computer From The Ground Up

Building a retro computer of some sort is a rite of passage for many of us, with some building replicas or restorations of old Commodores, Ataris, and other machines from decades past. Others go even further back, to the time of the Intel 8008 or earlier, and a dedicated few will build something completely novel. This project from [3DSage] falls squarely in the latter category, with his completely DIY computer built component by component from scratch, including the machine code needed to run it.

[3DSage] starts with the backbone of every computer: the clock. He first demonstrates how a pair of NOT gates with a set of capacitors can be used as a rudimentary clock pulse, then builds a more refined version with a 555 timer and potentiometer for adjustable rates. Then, it’s on to creating a binary counter, which is a fundamental part of the memory system for this small computer, and finally, allows this circuitry to behave like a normal computer. Using a set of switches to store values in memory and stepping through them with the clock, the computer can be programmed to do plenty of tasks just like a modern microcontroller.

[3DSage] built this project a few years ago and has used it for real-world applications such as controlling servos, LED arrays, playing music, and other tasks. Although he has to program it using his own machine code by hand, it’s a usable computer in many ways. If you want to eschew modernity and build a retro computer in the style of the 1960s, though, this piece goes through what it would have been like to build a similar system in the era when these computers were more common. If you have a switch fetish, you might like to see how real computers worked back then, too.

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A Vernier Take On A 3D Printer Extruder Indicator

A common way to visualize that a 3D printer’s extruder motor — which feeds the filament into the hot end — is moving is to attach a small indicator to the exposed end of the motor’s shaft. As the shaft turns, so does the attached indicator.

Small movements of the motor are therefore turned into larger movements of something else. So far, so simple. But what about visualizing very small extrusions, such as those tiny ones made during ironing?

[Jack]’s solution is a Vernier indicator for the extruder. Even the smallest movements of the extruder motor’s shaft are made clearly visible by such a device, as shown in the header image above. Vernier scales are more commonly found on measurement tools, and the concept is somewhat loosely borrowed here.

The usual way these lightweight indicators are attached is with a small magnet, and you can read all about them and see examples here.

This new design is basically the same, it simply has a background in a contrasting color added into the mix. [Jack]’s design is intended for the Bambu A1 printer, but the idea can be easily adapted. Give it a look if you find yourself yearning for a bit more visibility in your extruder movements.

DIY Quad-Motor Go-Kart Is A Thrilling Ride

[Peter Holderith] set out some time ago to build an electric go-kart. That by itself is not terribly unusual, but where his project diverts from the usual is in the fact that each of the four wheels has an integrated hub motor.

It might not look it, but each wheel has an integrated hub motor.

This kart project is a bit of a work in progress, with [Peter] previously building (then scrapping) a failed attempt at a cheap suspension system. But it’s completely operational with all four wheels able to deliver a monstrous amount of power despite being limited by the power supply (a battery pack salvaged from an Audi Q5 Hybrid).

The kart might not look it, but it weighs 177 pounds (80 kg) with the battery and motors accounting for nearly half of that. What is is like to drive? “Nothing short of thrilling,” says [Peter]. It’s got no suspension and is pretty bare bones, not to mention limited in power by the battery, but [Peter] finds it a satisfying drive that nevertheless delivers car-like cues in the driving experience. The build isn’t done, and [Peter] plans to see if more power is available by switching battery chemistries rather than add more battery weight.

Building and driving electric vehicles can be remarkably satisfying, and it’s an area in which hobbyists can meaningfully innovate. Self-balancing one-wheeled vehicles for example look like a ton of fun. Heck, researchers have discovered that even rats seem to enjoy driving just for the fun of it.