Supercon 2024: Exploring The Ocean With Open Source Hardware

If you had to guess, what do you think it would take to build an ocean-going buoy that could not only survive on its own without human intervention for more than two years, but return useful data the whole time? You’d probably assume such a feat would require beefy hardware, riding inside an expensive and relatively large watertight vessel of some type — and for good reason, the ocean is an unforgiving environment, and has sent far more robust hardware to the briny depths.

But as Wayne Pavalko found back in 2016, a little planning can go a long way. That’s when he launched the first of what he now calls Maker Buoys: a series of solar-powered drifting buoys that combine a collection of off-the-shelf sensor boards with an Arduino microcontroller and an Iridium Short-Burst Data (SBD) modem in a relatively simple watertight box.

He guessed that first buoy might last a few weeks to a month, but when he finally lost contact with it after 771 days, he realized there was real potential for reducing the cost and complexity of ocean research.

Wayne recalled the origin of his project and updated the audience on where it’s gone from there during his 2024 Supercon talk, Adventures in Ocean Tech: The Maker Buoy Journey. Even if you’re not interested in charting ocean currents with homebrew hardware, his story is an inspirational reminder that sometimes a fresh approach can help solve problems that might at first glance seem insurmountable.

Continue reading “Supercon 2024: Exploring The Ocean With Open Source Hardware”

Budget Schlieren Imaging Setup Uses 3D Printing To Reveal The Unseen

We’re suckers here for projects that let you see the unseeable, and [Ayden Wardell Aerospace] provides that on a budget with their $30 Schlieren Imaging Setup. The unseeable in question is differences in air density– or, more precisely, differences in the refractive index of the fluid the imaging set up makes use of, in this case air. Think of how you can see waves of “heat” on a warm day– that’s lower-density hot air refracting light as it rises. Schlieren photography takes advantage of this, allowing to analyze fluid flows– for example, the mach cones in a DIY rocket nozzle, which is what got [Ayden Wardell Aerospace] interested in the technique.

Shock diamonds from a homemade rocket nozzle imaged by this setup.
Examining exhaust makes this a useful tool for [Aerospace].
This is a ‘classic’ mirror-and-lamp Schlieren set up.  You put the system you wish to film near the focal plane of a spherical mirror, and camera and light source out at twice the focal distance. Rays deflected by changes in refractive index miss the camera– usually one places a razor blade precisely to block them, but [Ayden] found that when using a smart phone that was unnecessary, which shocked this author.

While it is possible that [Ayden Wardell Aerospace] has technically constructed a shadowgraph, they claim that carefully positioning the smartphone allows the sharp edge of the case to replace the razor blade. A shadowgraph, which shows the second derivative of density, is a perfectly valid technique for flow visualization, and is superior to Schlieren photography in some circumstances– when looking at shock waves, for example.

Regardless, the great thing about this project is that [Ayden Wardell Aerospace] provides us with STLs for the mirror and smartphone mounting, as well as providing a BOM and a clear instructional video. Rather than arguing in the comments if this is “truly” Schlieren imaging, grab a mirror, extrude some filament, and test it for yourself!

There are many ways to do Schlieren images. We’ve highighted background-oriented techniques, and seen how to do it with a moiré pattern, or even a selfie stick. Still, this is the first time 3D printing has gotten involved and the build video below is quick and worth watching for those sweet, sweet Schlieren images. Continue reading “Budget Schlieren Imaging Setup Uses 3D Printing To Reveal The Unseen”

Enigma buttons

Modernizing An Enigma Machine

This project by [Miro] is awesome, not only did he build a replica Enigma machine using modern technologies, but after completing it, he went back and revised several components to make it more usable. We’ve featured Enigma machines here before; they are complex combinations of mechanical and electrical components that form one of the most recognizable encryption methods in history.

His first Enigma machine was designed closely after the original. He used custom PCBs for the plugboard and lightboard, which significantly cleaned up the internal wiring. For the lightboard, he cleverly used a laser printer on semi-transparent paper to create crisp letters, illuminated from behind. For the keyboard, he again designed a custom PCB to connect all the switches. However, he encountered an unexpected setback due to error stack-up. We love that he took the time to document this issue and explain that the project didn’t come together perfectly on the first try and how some adjustments were needed along the way.
Continue reading “Modernizing An Enigma Machine”

A broken bolt is removed by welding on a hut and then using a wrench to unscrew.

Using A MIG Welder, Acetylene Torch, And Air Hammer To Remove A Broken Bolt

If your shop comes complete with a MIG welder, an acetylene torch, and an air hammer, then you have more options than most when it comes to removing broken bolts.

In this short video [Jim’s Automotive Machine Shop, Inc] takes us through the process of removing a broken manifold bolt: use a MIG welder to attach a washer, then attach a suitably sized nut and weld that onto the washer, heat the assembly with the acetylene torch, loosen up any corrosion on the threads by tapping with a hammer, then simply unscrew with your wrench! Everything is easy when you know how!

Of course if your shop doesn’t come complete with a MIG welder and acetylene torch you will have to get by with the old Easy Out screw extractor like the rest of us. And if you are faced with a nasty bolt situation keep in mind that lubrication can help.

Continue reading “Using A MIG Welder, Acetylene Torch, And Air Hammer To Remove A Broken Bolt”

An Absolute Zero Of A Project

How would you go about determining absolute zero? Intuitively, it seems like you’d need some complicated physics setup with lasers and maybe some liquid helium. But as it turns out, all you need is some simple lab glassware and a heat gun. And a laser, of course.

To be clear, the method that [Markus Bindhammer] describes in the video below is only an estimation of absolute zero via Charles’s Law, which describes how gases expand when heated. To gather the needed data, [Marb] used a 50-ml glass syringe mounted horizontally on a stand and fitted with a thermocouple. Across from the plunger of the syringe he placed a VL6180 laser time-of-flight sensor, to measure the displacement of the plunger as the air within it expands.

Data from the TOF sensor and the thermocouple were recorded by a microcontroller as the air inside the syringe was gently heated. Plotting the volume of the gas versus the temperature results shows a nicely linear relationship, and the linear regression can be used to calculate the temperature at which the volume of the gas would be zero. The result: -268.82°C, or only about four degrees off from the accepted value of -273.15°. Not too shabby.

[Marb] has been on a tear lately with science projects like these; check out his open-source blood glucose measurement method or his all-in-one electrochemistry lab.

Continue reading “An Absolute Zero Of A Project”

GK STM32 MCU-Based Handheld Game System

These days even a lowly microcontroller can easily trade blows with – or surpass – desktop systems of yesteryear, so it is little wonder that DIY handheld gaming systems based around an MCU are more capable than ever. A case in point is the GK handheld gaming system by [John Cronin], which uses an MCU from relatively new and very capable STM32H7S7 series, specifically the 225-pin STM32H7S7L8 in TFBGA package with a single Cortex-M7 clocked at 600 MHz and a 2D NeoChrom GPU.

Coupled with this MCU are 128 MB of XSPI (hexa-SPI) SDRAM, a 640×480 color touch screen, gyrometer, WiFi network support and the custom gkOS in the firmware for loading games off an internal SD card. A USB-C port is provided to both access said SD card’s contents and for recharging the internal Li-ion battery.

As can be seen in the demonstration video, it runs a wide variety of games, ranging from DOOM (of course), Quake, as well as Command and Conquer: Red Alert and emulators for many consoles, with the Mednafen project used to emulate Game Boy, Super Nintendo and other systems at 20+ FPS. Although there aren’t a lot of details on how optimized the current firmware is, it seems to be pretty capable already.

Continue reading “GK STM32 MCU-Based Handheld Game System”

Our hacker converts an old hard disk drive into a disc sander.

Making A Variable Speed Disc Sander From An Old Hard Drive

This short video from [ProShorts 101] shows us how to build a variable speed disc sander from not much more than an old hard drive.

We feel that as far as hacks go this one ticks all the boxes. It is clever, useful, and minimal yet comprehensive; it even has a speed control! Certainly this hack uses something in a way other than it was intended to be used.

Take this ingenuity and add an old hard drive from your junkbox, sandpaper, some glue, some wire, a battery pack, a motor driver, a power socket and a potentiometer, drill a few holes, glue a few pieces, and voilà! A disc sander! Of course the coat of paint was simply icing on the cake.

The little brother of this hack was done by the same hacker on a smaller hard drive and without the speed control, so check that out too.

One thing that took our interest while watching these videos is what tool the hacker used to cut sandpaper. Here we witnessed the use of both wire cutters and a craft knife. Perhaps when you’re cutting sandpaper you just have to accept that the process will wear out the sharp edge on your tool, regardless of which tool you use. If you have a hot tip for the best tool for the job when it comes to cutting sandpaper please let us know in the comments! (Also, did anyone catch what type of glue was used?)

If you’re interested in a sander but need something with a smaller form factor check out how to make a sander from a toothbrush! Continue reading “Making A Variable Speed Disc Sander From An Old Hard Drive”