[Ruud], the creator of [Capturing Dust], started his latest video with what most of us would consider a solved problem: the dust collection system for his shop already had a three-stage centrifugal dust separator with more than 99.7% efficiency. This wasn’t quite as efficient as it could be, though, so [Ruud]’s latest upgrade shrinks the size of the third stage while increasing efficiency to within a rounding error of 99.9%.

The old separation system had two stages to remove large and medium particles, and a third stage to remove fine particles. The last stage was made out of 100 mm acrylic tubing and 3D-printed parts, but [Ruud] planned to try replacing it with two parallel centrifugal separators made out of 70 mm tubing. Before he could do that, however, he redesigned the filter module to make it easier to weigh, allowing him to determine how much sawdust made it through the extractors. He also attached a U-tube manometer (a somewhat confusing name to hear on YouTube) to measure pressure loss across the extractor.

The new third stage used impellers to induce rotational airflow, then directed it against the circular walls around an air outlet. The first design used a low-profile collection bin, but this wasn’t keeping the dust out of the air stream well enough, so [Ruud] switched to using plastic jars. Initially, this didn’t perform as well as the old system, but a few airflow adjustments brought the efficiency up to 99.879%. In [Ruud]’s case, this meant that of 1.3 kilograms of fine sawdust, only 1.5 grams of dust made it through the separator to the filter, which is certainly impressive in our opinion. The design for this upgraded separator is available on GitHub.

[Ruud] based his design off of another 3D-printed dust separator, but adapted it to European fittings. Of course, the dust extractor is only one part of the problem; you’ll still need a dust routing system.

Thanks to [Keith Olson] for the tip!

There are a number of plans for DIY boats available online, so [Phil] went in search of one for a custom catamaran to travel the inland waterways of Canada. But none of the plans he found had options for electric motors so he modified one popular plan to include not only that, but plenty of other unique features as well throughout a long series of videos.

This isn’t [Phil]’s first electric boat, either. His first was a monohull with a long canopy above, providing shade for the occupants and a platform to mount solar panels. But that one was top heavy and unstable, so he pivoted to this catamaran design instead which has the perk of not only stability but a small draft. The plans were modified to use a similar propulsion system, though, but mounting the heavy panels on the roof of this boat was much less problematic. The roof itself retracts, and also includes some mosquito netting to enclose the cabin. He’s also added a head which is situated inside one of the hulls and has doors which fit into the retractable roof structure as well.

For navigating the peaceful inland waterways of Canada like the famous Rideau Canal, the Trent Severn Waterway which [Phil] frequents, or even quiet Ontario lake towns like Bobcaygeon we can’t imagine a better way to go that a peaceful, small electric boat like this one.

As summer rolls around in the northern hemisphere we’ll hope to see other solar electric boats like these out on the water, like this smaller electric-assisted kayak or this much larger solar electric houseboat.

One of the most paradoxical aspects of creating art is the fact that constraints, whether arbitrary or real, and whether in space, time, materials, or rules, often cause creativity to flourish rather than to wither. Picasso’s blue period, Gadsby by Ernest Vincent Wright, Tetris, and even the Volkswagen Beetle are all famous examples of constraint-driven artistic brilliance. Similarly, in the world of electronics we can always reach for a microcontroller but this project from [Peter] has the constraint of only using passive components, and it is all the better for it.

The project is a lockbox, a small container that reveals a small keypad and the associated locking circuitry when opened. When the correct combination of push buttons is pressed, the box unlocks the hidden drawer. This works by setting a series of hidden switches in a certain way to program the combination. These switches are connected through various diodes to a series of relays, so that each correct press of a button activates the next relay. When the final correct button is pushed, power is applied to a solenoid which unlocks the drawer. An incorrect button push will disable a relay providing power to the rest of the relays, resetting the system back to the start.

The project uses a lot of clever tricks to do all of this without using a single microcontroller, including using capacitors that carefully provide timing to the relays to make them behave properly rather than all energizing at the same time. The woodworking is also notable as well, with the circuit components highlighted when the lid is opened (but importantly, hiding the combination switches). Using relays for logic is not a novel concept, though; they can be used for all kinds of complex tasks including replacing transistors in single-board computers.

[Agatha] sent us this stunning multimeter she built as a gift for her mom. Dubbed the Mohmmeter — a playful nod to its ohmmeter function and her mom — this project combines technical ingenuity with heartfelt craftsmanship.

At its core, a Raspberry Pi Pico microcontroller reads the selector knob, controls relays, and lights up LEDs on the front panel to show the meter’s active range. The Mohmmeter offers two main measurement modes, each with two sub-ranges for greater precision across a wide spectrum.

She also included circuitry protections against reverse polarity and over-voltage, ensuring durability. There was also a great deal of effort put into ensuring it was accurate, as the device was put though its paces using a calibrated meter as reference to ensure the final product was as useful as it was beautiful.

The enclosure is a work of art, crafted from colorful wooden panels meticulously jointed together. Stamped brass plates label the meter’s ranges and functions, adding a steampunk flair. This thoughtful design reflects her dedication to creating something truly special.

Want to build a meter for mom, but she’s more of the goth type? The blacked-out Hydameter might be more here style.