Review And Teardown Of Economical Programmable DC Power Supply

June 24, 2021 by Donald Papp 14 Comments

[Kerry Wong] isn’t afraid to get his hands dirty, and is always more than willing to open things up and see what makes them tick. This time, he reviews and tears down the Topshak LW-3010EC programmable DC power supply, first putting the unit through its paces, then opens it up to see how it looks on the inside.

The Topshak LW-3010EC is in a family of reasonably economical power supplies made by a wide variety of manufacturers, which all share many of the same internals and basic construction. This one is both programmable as well as nice and compact, and [Kerry] compares and contrasts it with other power supplies in the same range as he tests the functions and checks over the internals.

Overall, [Kerry] seems pleased with the unit. You can watch him put the device through its paces in the video embedded below, which ends with him opening it up and explaining what’s inside. If you’ve ever been curious about what’s inside one of these power supplies and how they can be expected to perform, be sure to fire up the video below the page break.

Speaking of power supplies, most of us have ready access to ATX power supplies. They are awfully capable pieces of hardware, and hackable in their own way. Our own Jenny List will tell you everything you need to know about the ATX power supply, and how to put it to new uses.

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Big Spinning Disk Makes A Small Color Video Display

June 23, 2021 by Donald Papp 6 Comments

Believe it or not, the Mickey Mouse clip used for this demonstration is actually in the public domain.

The earliest televisions used a spinning disk technology called the Nipkow disk, which is exactly what [Science ‘n’ Stuff] recreated with their Arduino-based mechanical color television (video link, also embedded below.) The device reads video and audio from an SD card, and displays the video using a precisely-timed RGB LED visible through a perforated spinning disk. The persistence of vision effect results in a video that is small, relative to the size of the disk, but perfectly watchable. A twist is that the video is in color!

A Nipkow disk is a fairly simple and electromechanical device that relies on timing; something a modern microcontroller and RGB LED is perfectly capable of delivering. In this device, the holes in the disk create 32 vertical scanlines with 96 “pixels” making up each of those lines. Spinning disk technology was always limited to being monochromatic, but in this implementation, each “pixel” is given its own unique color by adjusting the RGB LED accordingly.

The first video shows off the device and demonstrates it working; note that it may look like there are multiple little screens, but the center one can be thought of as the “true” display with the others essentially being artifacts due to light leakage. If you’re interested in the nuts and bolts of exactly how a Nipkow disk works, then the second video is what you’ll be more interested in, because it goes through all the details of exactly how everything functions.

Another neat thing about Nipkow disks is that image acquisition is really not much more complex than image display.

[via Arduino Blog]

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See Acorn Archimedes Get Repaired And Refurbished, In Glorious Detail

June 21, 2021 by Donald Papp 3 Comments

Want to see a 90s-era Acorn Archimedes A3020 home computer get opened up, refurbished, and taken for a test drive? Don’t miss [drygol]’s great writeup on Retrohax, because it’s got all that, and more!

A modern upgrade allowing the use of a CF card in place of an internal hard drive, via a CF2IDE adapter and 3D-printed fixture.

The Archimedes was a line of ARM-based personal computers by Acorn Computers, released in the late 80s and discontinued in the 90s as Macintosh and IBM PC-compatible machines ultimately dominated. They were capable machines for their time, and [drygol] refurbished an original back into working order while installing a few upgrades at the same time.

The first order of business was to open the machine up and inspect the internals. Visible corrosion gets cleaned up with oxalic acid, old electrolytic capacitors are replaced as a matter of course, and any corroded traces get careful repair. Removing corrosion from sockets requires desoldering the part for cleaning then re-soldering, so this whole process can be a lot of work. Fortunately, vintage hardware was often designed with hand-assembly in mind, so parts tend to be accessible for servicing with decent visibility in the process. The keyboard was entirely disassembled and de-yellowed, yielding an eye-poppingly attractive result.

Once the computer itself was working properly, it was time for a few modern upgrades. One was to give the machine an adapter to use a CF card in place of an internal IDE hard drive, and [drygol] did a great job of using a 3D-printed piece to make the CF2IDE adapter look like a factory offering. The internal floppy drive was also replaced with a GOTEK floppy emulator (also with a 3D-printed adapter) for another modern upgrade.

The fully refurbished and upgraded machine looks slick, so watch the Acorn Archimedes A3020 show off what it can do in the video (embedded below), and maybe feel a bit of nostalgia.

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The Regulatory Side Of Rolling Your Own Moderate Solar Farm

June 17, 2021 by Donald Papp 25 Comments

[Russell Graves] lives in Idaho and recently connected his solar installation to the grid, which meant adhering to regulatory requirements for both the National Electric Code (NEC) as well as complying with the local power company’s own regulations. His blog post is an interesting look at the whole regulatory process and experience, and is of interest to anyone curious about running their own solar farm, whether they have plans to connect it to the grid or not.

A circuit breaker that met NEC code, but not the power company’s requirements.

The power company has a very different set of priorities from the NEC, and part of [Russell]’s experience was in having to meet requirements that weren’t documented in the expected places, so study of the materials didn’t cut it. In particular, the power company needed the system to have disconnects with conductors that visually move out of position when disconnected. [Russell] was using NEC-compliant circuit breakers that met NEC code, but they didn’t meet the power company requirement for conductors that can be visually confirmed as being physically disconnected. Facing a deadline, [Russell] managed to finesse a compliant system that was approved, and everything got signed off just as winter hit.

How well does his solar farm work out? Sometimes the panels produce a lot of power, sometimes nearly nothing, but it has been up and running for all of winter and into spring. Over the winter, [Russell] pulled a total of 3.1 MWh from the grid, mainly because his home is heated with electric power. But once spring hit, he started pushing considerably more into the grid than he was pulling; on some days his setup produces around 95 kWh, of which about 70 kWh gets exported.

[Russell] didn’t go straight to setting up his own modest solar farm; we saw how he began by making his own ideal of a perfect off-grid office shed that ran on solar power, but it has certainly evolved since then and we’re delighted to see that he’s been documenting every bit of the journey.

Modular Box Design Eases Silicone Mold-Making

June 16, 2021 by Donald Papp 13 Comments

Resin casting is a fantastic way to produce highly detailed parts in a wide variety of colors and properties, and while the process isn’t complicated, it does require a certain amount of care and setup. Most molds are made by putting a part into a custom-made disposable box and pouring silicone over it, but [Foaly] was finding the process of making and re-making those boxes a bit less optimized than it could be. That led to this design for a re-usable, modular, adjustable mold box that makes the workflow for small parts considerably more efficient.

The walls of the adjustable box are four identical 3D-printed parts with captive magnets, and the base of the box is a piece of laser-cut steel sheet upon which the magnetic walls attach. The positioning and polarity of the magnets are such that the box can be assembled in a variety of sizes, and multiple walls can be stacked to make a taller mold. To aid cleanup and help prevent contamination that might interfere with curing, the inner surfaces of each piece are coated in Kapton tape.

The result is a modular box that can be used and re-used, and doesn’t slow down the process of creating and iterating on mold designs. The system as designed is intended for small parts, but [Foaly] feels there is (probably) no reason it can’t be scaled up to some degree. Interested? The design files are available from the project’s GitHub repository, and if you need to brush up a bit on how resin casting works, you can read all about it here.

Tiny Mechanical Keyboard, Powered By Pi Pico

June 9, 2021 by Donald Papp 18 Comments

For some applications, smaller is better and that is precisely the thinking behind a diminutive keyboard like the PiPi Gherkin, which is designed to use the Raspberry Pi Pico as its controller. This keyboard may have only 30 keys in total, but they are full-sized for comfort and don’t let the scant layout mislead you. It has more functionality than it would seem to at first glance; the entire bottom row acts as dual function tap/hold keys, allowing the keyboard to shift layers on the fly.

This keyboard definitely has a a thoughtful layout, and we’re not just talking about the tap/shift functionality. We especially like the way the Pi Pico is tucked neatly underneath the main PCB, taking up very little room while exposing its USB connector between two standoffs for easy access without requiring an adapter, or wiring a separate plug.

If the Gherkin sounds familiar, we’ve seen it before as part of this lunchbox cyberdeck build, where the small size allowed it to take up impressively little room. The shifting might take a little getting used to, but it’s a clean design that uses full sized keys, so when it comes to small keyboards one could certainly do worse.

Soldering Iron Plus Camera Gimbal Helps Cancel Out Hacker’s Hand Tremors

June 4, 2021 by Donald Papp 39 Comments

Soldering requires steady hands, so when [Jonathan Gleich] sadly developed a condition called an essential tremor affecting his hands, soldering became much more difficult. But one day, while [Jonathan] was chatting with a friend, they were visited by the Good Ideas Fairy and in true hacker fashion, he ended up repurposing a handheld camera stabilizing gimbal to hold a soldering iron instead of a camera or smartphone. Now instead of the gimbal cancelling out hand movements to keep a camera steady, it instead helps keep a soldering iron steady.

While the inner workings of the cheap gimbal unit didn’t need modification, there were a couple of things that needed work before the project came together. The first was to set up a way to quickly and easily connect and disconnect the soldering iron from the gimbal. Thanks to a dovetail-like connector, the iron can be safely stored in its regular holster and only attached when needed.

The other modification is more subtle. The stabilizer motors expect to be managing something like a smartphone, but a soldering iron is both lighter and differently balanced. That meant that the system worked, but not as well as it needed to. After using some small lead weights to tweak the mass and center of gravity of the soldering iron — making it feel and move a bit more like an iPhone, as far as the gimbal was concerned — results were improved.

The soldering iron stabilizer works well enough for now, but we don’t doubt that [Jonathan] already has further tweaks in mind. This is a wonderful repurposing of a consumer device into an assistive aid, so watch it in action in the short video embedded below.

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