An Anodiser That Does Gradients

Anodizing aluminium, the process of electrolytic build up of the metal’s the oxide layer in the presence of dyes to create colored effects, is such a well-established process that we probably all have anodized items within sight. It’s usually an industrial mass-production process that creates a uniform result, but there’s an anodizing machine from a Dutch design studio which promises to place anodized aluminium in a new light. Studio Loop Loop’s Magic Color Machine enacts a small-scale automated anodizing process driven by a microcontroller, and is capable of effects such as gradated colors.

Unfortunately their website is long on marketing and short on technical details, but the basic function of a line of chemical baths with a pulley to lower and lift the item being anodized shouldn’t be too difficult for any Hackaday reader to understand. There’s a short video clip posted on Instagram which also gives some idea. It’s a powerful idea that should lead to some eye-catching work for their studio, but its interest here lies in the techniques it might inspire others to try. We look forward to an open-source version of a gradated anodize. Meanwhile if anodizing takes your fancy, it’s a subject we’ve visited before.

An Affordable Reference Mic You Can Build Yourself

Reference mics are vital tools for audio work. They’re prized for their flat frequency response, and are often used for characterizing the audio response of a room or space. OpenRefMic aims to be an open source design for producing reference mics without paying exorbitant retail prices.

The heart of the build is a preamplifier that runs off standard 48 V phantom power, and is responsible for both biasing the electret microphone element and acting as a buffer for the mic signal. It’s designed specifically to work with the PUI AOM-5024L-HD-F-R mic capsule, chosen for its good performance and low noise characteristics. However, other electric mics should work, too. The hardware is wrapped up in a 3D printed case which can readily be made on most basic printers. It’s complete with a press-fit grille that holds the mic capsule in place.

The prime goal of the project is low noise; the project creator, [loudifier], notes that most commercial reference mics focus first on flat frequency response and then reducing noise. OpenRefMic performs well in this area, and its lack of a perfectly flat frequency response is countered with calibrated equalization. It also works with regular pro-grade XLR cables and phantom power, rather than needing fancy laboratory-spec cables and interfaces.

The final result is a credit to [loudifier], who demonstrates a strong understanding of the principles of reference mic design. We’ve seen some other great low-cost reference mics recently, too!

Not On The Internet

Whenever you need to know something, you just look it up on the Internet, right? Using the search engine of your choice, you type in a couple keywords, hit enter, and you’re set. Any datasheet, any protocol specification, any obscure runtime error, any time. Heck, you can most often find some sample code implementing whatever it is you’re looking for. In a minute or so.

It is so truly easy to find everything technical that I take it entirely for granted. In fact, I had entirely forgotten that we live in a hacker’s utopia until a couple nights ago, when it happened again: I wanted to find something that isn’t on the Internet. Now, to be fair, it’s probably out there and I just need to dig a little deeper, but the shock of not instantly finding the answer to a random esoteric question reminded me how lucky we actually are 99.99% of the time when we do find the answer straight away.

So great job, global hive-mind of über-nerds! This was one of the founding dreams of the Internet, that all information would be available to everyone anywhere, and it’s essentially working. Never mind that we can stream movies or have telcos with people on the other side of the globe – when I want a Python library for decoding Kansas City Standard audio data, it’s at my fingertips. Detailed SCSI specifications? Check.

But what was my search, you ask? Kristina and I were talking about Teddy Ruxpin, and I thought that the specification for the servo track on the tape would certainly have been reverse engineered and well documented. And I’m still sure it is – I was just shocked that I couldn’t instantly find it. The last time this happened to me, it was the datasheet for the chips that make up a Speak & Spell, and it turned out that I just needed to dig a lot harder. So I haven’t given up hope yet.

And deep down, I’m a little bit happy that I found a hole in the Internet. It gives Kristina and me an excuse to reverse engineer the format ourselves. Sometimes ignorance is bliss. But for the rest of those times, when I really want the answer to a niche tech question, thanks everyone!

Dual Power Supply In A Pinch

Recently I needed a dual voltage power supply to test a newly-arrived PCB, but my usual beast of a lab power supply was temporarily at a client’s site. I had a FNIRSI programmable power supply which would have been perfect, but alas, I had only one. While digging around in my junk box I found several USB-C power-delivery “trigger” boards which I bought for an upcoming project. These seemed almost too small for the task at hand, but after a little research I realized they would work quite well.

The ones I had used the Injoinic IP2721 USB-C power delivery chip, commonly used in many of these boards. Mine had been sold pre-configured for certain output voltages, but they were easy to re-jumper to the voltages I needed, +5 VDC  and +20 VDC. The most challenging aspect was physically using them — they are the size of a fingernail. This version had through-hole output pads on 0.1″ centers, so I decided to solder them to the base of a standard MTA pin header. A few crimps later and I was up and running, along with the requisite pair of USB-C cables and power adapters.

For just a few dollars each, these trigger boards are useful to have in your toolbox, both for individual projects and for use in a pinch. We reviewed these modules a couple of years ago, and check out the far more flexible PD Micro that we covered last year.

Singing Fish Nails Sea Shanty Audition

The Big Mouth Billy Bass and other singing fish were a scourge first delivered to us in the late 90s. [Kevin Heckart] has been teaching them to sing new songs without the tinny sound quality and hokey folk tunes. For this, he must be applauded.

A Teensy 4.1 or Teensy 3.2 is used to power [Kevin]’s various singing fish builds. There are two motors inside a singing fish, typically — one motor to pivot the fish’s body, and one to open and close the mouth. Hook these up to a motor driver, and command that with the Teensy, and you’re up and running. To sync the fish with the music, MIDI data is sent to the Teensy over USB. The Teensy takes in note data and uses this to command the motors to make the fish appear to sing along.

The tutorial linked above is a great way to learn how the hack was achieved. However, the real money is in the performance. A video of [Kevin]’s fishy chorus performing the famous Wellerman sea shanty has over 50 million views on YouTube and he’s collected over 26 million likes on Tiktok.

Sometimes the simple hacks are the ones that bring the most joy. Video after the break.

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Kotonki: Agricultural Vehicle Built For Customization

Agriculture on any scale involves many tasks that require lifting, hauling, pushing, and pulling. On many modern farms, these tasks are often done using an array of specialized (and expensive) equipment. This puts many small-scale farmers, especially those in developing countries, under significant financial pressure. These challenges led a South African engineering firm to develop the Kotonki, a low-cost hydraulically powered utility vehicle that can be customized for a wide variety of use cases. Video after the break.

The name Kotonki is derived from the Setswana phrase for a donkey kart. It is in essence a self-propelled hydraulic power pack, capable of hauling 1 ton of anything that can fit on its load bed. It comes in front-wheel drive or four-wheel drive versions, with each wheel individually driven by a hydraulic motor. The simple welded steel frame articulates around a double pivot, which allows it to keep all 4 wheels on the ground over any terrain. At a max speed of 10 km/h it won’t win any races, but neither would most other agricultural vehicles. The Kotonki is built mostly using off-the-shelf components and is powered by a common 12HP Honda engine. In the world of DRM agricultural equipment, this makes for simple repairs, low running costs, and easy customization for the task at hand. This can include mounting log splitters, water pumps, lifting beds, or anything else that can be driven by its hydraulic and rotary PTOs (Power Take-Off).

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Computer Vision Extracts Lightning From Footage

Lightning is one of the more mysterious and fascinating phenomenon on the planet. Extremely powerful, but each strike on average only has enough energy to power an incandescent bulb for an hour. The exact mechanism that starts a lightning strike is still not well understood. Yet it happens 45 times per second somewhere on the planet. While we may not gain a deeper scientific appreciation of lightning anytime soon, but we can capture it in various photography thanks to this project which leverages computer vision machine learning to pull out the best frames of lightning.

The project’s creator, [Liam], built this as a tool for stormchasers and photographers so that they can film large amounts of time and not have to go back through their footage manually to pull out the frames with lightning strikes. The project borrows from a similar project, but this one adds Python 3 capabilities and runs on a tiny netbook for more easy field deployment. It uses OpenCV for object recognition, using video files as the source data, and features different modes to recognize different types of lightning.

The software is free and open source, and releases are supported for both Windows and Linux. So far, [Liam] has been able to capture all kinds of electrical atmospheric phenomenon with it including lightning, red sprites, and elves. We don’t see too many projects involving lightning around here, partly because humans can only generate a fraction of the voltage potential needed for the average lightning strike.