Quasi-Quantifying Qubits For 100 Quid

As part of his multi-year project to build a quantum computer, hacakday.io poster [skywo1f] has shared with us his most recent accomplishment — a Nuclear Magnetic Resonance Spectrometer, which he built for less than $100.

The NMR spectrometer is designed to disturb protons, which naturally line up according to the Earth’s magnetic field, using an electric coil. Once disturbed, the protons nutate (a fancy physics word for wobble), and flip quantum spin states. [skywo1f]’s NMR device can detect these spin state changes, as he demonstrates with a series of control experiments designed to eliminate sources of false positives (which can be annoyingly prevalent in experimental physics). His newest experimental device includes a number of improvements over previous iterations, including proper shielding, quieter power topology, and better coil winding in the core of the device. Everything was assembled with cost in mind, while remaining sensitive enough to conduct experiments — the whole thing is even driven by a Raspberry Pi Pico.

Here at Hackaday, we love to see experiments that should be happening in million-dollar laboratories chugging along on kitchen tables, like this magnetohydrodynamic drive system or some good old-fashioned PCB etching. [skywo1f] doesn’t seem to be running any quantum calculations yet, but the NMR device is an important building block in one flavor of quantum computer, so we’re excited to see where he takes his work next.

Two views of a motor are shown. On the left, a ring of copper-wire-wound stator arms is visible inside a ring of magnets. Inside this, a planetary gearbox is visible, with three mid-sized gears surrounding a small central gear. On the right, the same motor is shown, but with the internal components mostly covered by a black faceplate with brass inserts.

A Budget Quasi-Direct-Drive Motor Inspired By MIT’s Mini Cheetah

It’s an unfortunate fact that when a scientist at MIT describes an exciting new piece of hardware as “low-cost,” it might not mean the same thing as if a hobbyist had said it. [Caden Kraft] encountered this disparity when he was building a SCARA arm and needed good actuators. An actuator like those on MIT’s Mini Cheetah would have been ideal, but they cost about $300. Instead, [Caden] designed his own actuator, much cheaper but still with excellent performance.

The actuator [Caden] built is a quasi-direct-drive actuator, which combines a brushless DC motor with an integrated gearbox in a small, efficient package. [Caden] wanted all of the custom parts in the motor to be 3D printed, so a backing iron for the permanent magnets was out of the question. Instead, he arranged the magnets to form a Halbach array; according to his simulations, this gave almost identical performance to a motor with a backing iron. As a side benefit, this reduced the inertia of the rotor and let it reverse more easily.

To increase torque, [Caden] used a planetary gearbox with cycloidal gear profiles, which may be the stars of the show here. These reduced backlash, decreased stress concentration on the teeth, and were easier to 3D print. He found a Python program to generate planetary gearbox designs, but ended up creating a fork with the ability to export 3D files. The motor’s stator was commercially-bought and hand-wound, and the finished drive integrates a cheap embedded motor controller. Continue reading “A Budget Quasi-Direct-Drive Motor Inspired By MIT’s Mini Cheetah”

Picture of front and back of thumb drive enclosure

Jcorp Nomad: ESP32-S3 Offline Media Server In A Thumbdrive

[Jackson Studner] wrote in to let us know about his ESP32-based media server: Jcorp Nomad.

This project uses a ESP32-S3 to create a WiFi hotspot you can connect to from your devices. The hotspot is a captive portal which directs the user to a web-interface comprised of static HTML assets which are in situ with the various media on an attached SD card formatted with a FAT32 file system. The static HTML assets are generated by the media.py Python 3 script when the ESP32 boots.

This project exists because the typical Raspberry Pi media server costs more than an ESP32 does. The ESP32 is smaller too, and demands less power.

According to [Jackson] this ESP32-based solution can support at least four concurrent viewers. The captive portal is implemented with DNS and HTTP services from the ESP32. The firmware is an Arduino project that integrates a bunch of libraries to provide the necessary services. The Jcorp Nomad media template supports Books (in pdf files), Music (in mp3 files), and Movies and Shows (in mp4 files). Also there is a convention for including JPEG files which can represent media in the user-interface.

And the icing on the cake? The project files include STL files so you can 3D print an enclosure. All in all, a very nice hack.

Playing Snake With Digital Microfluidics

Display technology has come a long way since the advent of the CRT in the late 1800s (yes, really!). Since then, we’ve enjoyed the Nixie tubes, flip dots, gas plasma, LCD, LED, ePaper, the list goes on. Now, there’s a new kid on the block — water.

[Steve Mould] recently got his hands on an OpenDrop — an open-source digital microfluidics platform for biology research. It’s essentially a grid of electrodes coated in a dielectric. Water sits atop this insulating layer, and due to its polarized nature, droplets can be moved around the grid by voltages applied to the electrodes. The original intent was to automate experiments (see 8:19 in the video below for some wild examples), but [Steve] had far more important uses in mind.

When [Steve]’s 1,000 device shipped from Switzerland, it was destined for greatness. It was turned into a game console for classics such as Pac-Man, Frogger, and of course, Snake. With help from the OpenDrop’s inventor (and Copilot), he built paired-down versions of the games that could run on the 8×14 “pixel” grid. Pac-Man in particular proved difficult, because due to the conservation of mass, whenever Pac-Man ate a ghost, he grew and eventually became unwieldy. Fortunately, Snake is one of the few videogames that actually respects the laws of classical mechanics, as the snake grows by one unit each time it consumes food.

[Steve] has also issued a challenge — if you code up another game, he’ll run it on his OpenDrop. He’s even offering a prize for the first working Tetris implementation, so be sure to check out his source code linked in the video description as a starting point. We’ve seen Tetris on oscilloscopes and 3D LED matrices before, so it’s about time we get a watery implementation.

Continue reading “Playing Snake With Digital Microfluidics”

Presenter holds an induction lamp bulb

An Induction Lamp Made On The Same Principle As Ordinary Fluorescent Lamp

Over on YouTube, [Technology Connections] has a new video: Induction lamps: fluorescent lighting’s final form.

This video is about a wireless fluorescent light which uses induction to transfer power from the electrical system into the lamp. As this lamp doesn’t require wiring it is not prone to “sputtering” as typical fluorescent lights are, thus improving the working life by an order of magnitude. As explained in the video sputtering is the process where the electrodes in a typical fluorescent lamp lose their material over time until they lose their ability to emit electrons at all.

This particular lamp has a power rating of 200 W and light output of 16,000 lumens, which is quite good. But the truly remarkable thing about this type of lighting is its service life. As the lamp is simply a phosphor-coated tube filled with argon gas and a pellet of mercury amalgam it has a theoretically unlimited lifespan. Or let’s call it 23 years.

Given that the service life is so good, why don’t we see induction lamps everywhere? The answer is that the electronics to support them are very expensive, and these days LED lighting has trounced every lighting technology that we’ve ever made in terms of energy efficiency, quality of light, and so on. So induction lamps are obsolete before they ever had their day. Still pretty interesting technology though!

Continue reading “An Induction Lamp Made On The Same Principle As Ordinary Fluorescent Lamp”

Photo showing the wire-wrapped version and PCB version of MyCPU side-by-side.

This Homebrew CPU Got Its Start In The 1990s

[Sylvain Fortin] recently wrote in to tell us about his Homebrew CPU Project, and the story behind this one is truly remarkable.

He began working on this toy CPU back in 1994, over thirty years ago. After learning about the 74LS181 ALU in college he decided to build his own CPU. He made considerable progress back in the 90s and then shelved the project until the pandemic hit when he picked it back up again and started adding some new features. A little later on, a board house approached him with an offer to cover the production cost if he’d like to redo the wire-wrapped project on a PCB. The resulting KiCad files are in the GitHub repository for anyone who wants to play along at home.

An early prototype on breadboard

The ALU on [Sylvain]’s CPU is a 1-bit ALU which he describes as essentially a selectable gate: OR, XOR, AND, NOT. It requires more clock steps to compute something like an addition, but, he tells us, it’s much more challenging and interesting to manage at the microcode level. On his project page you will find various support software written in C#, such as an op-code assembler and a microcode assembler, among other things.

For debugging [Sylvain] started out with das blinkin LEDs but found them too limiting in short order. He was able to upgrade to a 136 channel Agilent 1670G Benchtop Logic Analyzer which he was fortunate to score for cheap on eBay. You can tell this thing is old from the floppy drive on the front panel but it is rocking 136 channels which is seriously OP.

The PCB version is a great improvement but we were interested in the initial wire-wrapped version too. We asked [Sylvain] for photos of the wire-wrapping and he obliged. There’s just something awesome about a wire-wrapped project, don’t you think? If you’re interested in wire-wrapping check out Wire Wrap 101.

fastener counter

Fastener Fusion: Automating The Art Of Counting

Counting objects is an ideal task for automation, and when focusing on a single type of object, there are many effective solutions. But what if you need to count hundreds of different objects? That’s the challenge [Christopher] tackled with his latest addition to his impressive automation projects. (Video, embedded below.)

[Christopher] has released a series of videos showcasing a containerized counting system for various fasteners, available on his YouTube channel. Previously, he built remarkable devices to count and sort fastener hardware for automated packaging, but those systems were designed for a single fastener type. He effectively highlights the vast complexity of the fastener ecosystem, where each diameter has dozens of lengths, multiple finishes, various head shapes, and more.

To address this, he developed a machine that accepts standardized containers of fastener hardware. These uniform boxes can hold anything from a small M2 countersunk screw to a large M8 cap head bolt and everything in between. To identify the loaded box and determine the appropriate operations, the machine features an RFID reader that scans each box’s unique tag.

Once a box is loaded, the machine tilts it to begin counting fasteners using a clever combination of moving platforms, an optical sensor, and gravity. A shelf first pushes a random number of fasteners onto an adjustable ledge. A second moving platform then sweeps excess fasteners off, leaving only those properly aligned. It’s no surprise this system has nine degrees of freedom. The ledge then moves into view of a sensor from a flatbed scanner, which detects object locations with an impressive 0.04 mm resolution across its length—remarkable for such an affordable sensor. At this point, the system knows how many fasteners are on the ledge. If the count exceeds the desired number, a sloped opening allows the ledge to lift just high enough to release the correct amount, ensuring precision.

The ingenuity continues after the initial count. A secondary counting method uses weight, with a load cell connected to the bin where fasteners drop. A clever over-center mechanism decouples the tilting system from the load cell to ensure accurate readings. We love automation projects, and this one incorporates so many ingenious design elements that it’s sure to inspire others for their future endeavors.

Continue reading “Fastener Fusion: Automating The Art Of Counting”