The Musical Instrument Digital Interface has a great acronym that is both nice to say and cleanly descriptive. The standard for talking to musical instruments relies on a serial signal at 31250 bps, which makes it easy to transmit using any old microcontroller UART with a settable baud rate. However, [Kevin] has dived into explore the utility of sending MIDI signals over I2C instead.
With a bit of hacking at the Arduino MIDI library, [Kevin] was able to get the microcontroller outputting MIDI data over the I2C interface, and developed a useful generic I2C MIDI transport for the platform. His first tests involved using this technique in concert with Gravity dual UART modules. After he successfully got one running, [Kevin] realised that four could be hooked up to a single Arduino, giving it 8 serial UARTS, or, in another way of thinking, 8 MIDI outputs.
At its greatest level of development, [Kevin] shows off his I2C MIDI chops by getting a single Raspberry Pi Pico delivering MIDI signals to 8 Arduinos, all over I2C. All the Arduinos are daisy-chained with their 5V and I2C lines wired together, and the system basically swaps out traditional MIDI channels for I2C addresses instead.
There’s not a whole lot of obvious killer applications for this, but if you want to send MIDI data to a bunch of microcontrollers, you might find it easier daisy-chaining I2C rather than hopping around with a serial line in the classic MIDI-IN/MIDI-THRU fashion.
Imagine the scene: You’re puttering along in your vehicle when, at least an hour from the nearest help, one of your tires starts losing air. Not to worry! You’ve got a spare tire along with the tools and knowhow to change it. And if that fails, you can call roadside assistance. But what if your car isn’t a car, has metal wheels for which no spares are available, and the nearest help is 200 million miles away? You just might be a Jet Propulsion Laboratory Engineer on the Curiosity Mars Rover mission, who in 2017 was charged with creating a new driving algorithm designed to extend the life of the wheels.
You could say that the Curiosity Mars rover is the ultimate off-road vehicle, and as such it has to deal with conditions that are in some ways not that different from some locations here on Earth. Earth bound rock crawlers use long travel suspensions, specialized drivetrains, and locking differentials to keep the tires on the ground and prevent a loss of traction.
On Mars, sand and rocks dominate the landscape, and a rover must navigate around the worst of it. It’s inevitable that, just like a terrestrial off-roader, the Mars rovers will spin a tire now and then when a wheel loses traction. The Mars rovers also have a specialized drivetrain and long travel suspensions. They don’t employ differentials, though, so how are they to prevent a loss of traction and the damaging wheel spin that ensues? This where the aforementioned traction control algorithm comes in.
By controlling the rotation of the wheels with less traction, they can still contribute to the motion of the vehicle while avoiding rock rash. Be sure to check out the excellent article at JPL’s website for a full explanation of their methodology and the added benefits of uploading new traction control algorithms from 200 million miles away! No doubt the Perseverance Mars rover has also benefited from this research.
Maybe it’s the humidity, maybe it’s the cold weather. Something is making [Laura Kampf]’s nice fabric-backed sandpaper curl up into scrolls the second it comes out of the package. So you can understand why she urgently wanted to make a storage system that would be easy to flip through like a record bin, but also provide enough pressure to keep the papers flat.
Although [Laura] didn’t know what exactly the end result would be, she got started on it anyway — that’s a great way to get more projects off the drawing board and past the finish line. It worked out, because she got a great idea while building the box and using nice cam clamps to hold the finger joints together as the glue dried. Since she already had a bunch of these cam clamps in different lengths lying around, why not use a couple of them for this?
[Laura] has two major classifications of sandpaper — paper-backed and fabric-backed — and built them separate boxen using two clamps for each box. She joined the pins with a DIY handle in order to move the cams in unison, so all she has to do is pull out to flip through the papers, and push the handle back and down to re-pressurize the stack for storage. Be sure to check out the build and demo video after the break.
It used to be that to play a console game, you just had to plug in a cartridge or put a CD/DVD in the optical drive. But these days, with modern titles ballooning up to as much as 100 GB, you’ve got no choice but to store them on the system’s internal hard disk drive. While that can lead to some uncomfortable data management decisions, at least it means you don’t have to get up off the couch to switch games anymore.
Which is precisely why the MC2SIO project for the PlayStation 2 is so exciting. As [Tito] explains in his latest Macho Nacho Productions video, this simple adapter lets you connect an SD card up to the console’s Memory Card slots and use that to hold ISOs of your favorite games. With the appropriate homebrew software loaded up, your PS2 becomes a veritable jukebox of classic games.
There’s a fine line between simple feature creep and going over the top when it comes to project design. It’s hard to say exactly where that line is, but we’re pretty sure that this filament dry box has at least stepped over it, and might even have erased it entirely.
Sure, we all know the value of storing 3D printer filament under controlled conditions, to prevent the hygroscopic plastics from picking up atmospheric moisture. But [Sasa Karanovic] must really, REALLY hate the printing artifacts that result. Starting with a commercially available dry box that already had a built-in heating element, [Sasa] took it to the next level by replacing the controller and display with an ESP32. He added a fan to improve air circulation inside the enclosure and prevent stratification, as well as temperature and humidity sensors. Not satisfied with simply switching the heating element on and off at specific setpoints, he also implemented a PID loop to maintain a constant temperature. And of course, there’s a web UI and an API available for third-party control and monitoring.
The video below details [Sasa]’s design thoughts and goes into some detail on construction and performance. And while we may kid that this design is over-the-top, what really comes through is that this is a showcase for design ideas not only for one application, but for hardware projects in general. There are certainly simpler heated dry box designs, and zero-cost solutions as well, but sometimes going overboard has its own value too.
Though some of us are heavily assisted by smart phone apps and delivery, humans don’t need GPS to find food. We know where the fridge is. The grocery store. The drive-thru. And we don’t really need a map to find shelter, in the sense that shelter is easily identifiable in a storm. You might say that our most important navigation skills are innate, at least when we’re within our normal environment. Drop us in another city and we can probably still identify viable overhangs, cafes, and food stalls.
After verifying that all the macro buttons worked, [Taylor] tore down the mouse and extracted the daughterboard, then removed the sticker that held the rubber dome actuators in place. Then they wired up twelve Kailh box jades to the pads, doing some nice diagonal work with bare 30 AWG wire to join all the common pins together.
[Taylor] designed and printed a simple enclosure that’s a slim 21.5 mm tall including the switch plate, and then made a dozen keycaps to match. That was until [Taylor] remembered some relegendable keycaps they had lying around — the kind that let you print your own labels and trap them underneath clear plastic. The only problem was that they are stemmed for some cylindrical actuator, so [Taylor] designed an adapter piece so they would fit on MX-style sliders. Be sure to check out the build video after the break.