Wire-frame image of gearbox, setup as a differential

Roller Gearbox Allows For New Angles In Robotics

May 22, 2025 by 17 Comments

DIY mechatronics always has some unique challenges when relying on simple tools. 3D printing enables some great abilities but high precision gearboxes are still a difficult problem for many. Answering this problem, [Sergei Mishin] has developed a very interesting gearbox solution based on a research paper looking into simple rollers instead of traditional gears. The unique attributes of the design come from the ability to have a compact angled gearbox similar to a bevel gearbox.

Multiple rollers rest on a simple shaft allowing each roller to have independent rotation. This is important because having a circular crown gear for angled transmission creates different rotation speeds. In [Sergei]’s testing, he found that his example gearbox could withstand 9 Nm with the actual adapter breaking before the gearbox showing decent strength.

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Jettison Sails For Electric Propulsion

May 21, 2025 by 30 Comments

Although there are some ferries and commercial boats that use a multi-hull design, the most recognizable catamarans by far are those used for sailing. They have a number of advantages over monohull boats including higher stability, shallower draft, more deck space, and often less drag. Of course, these advantages aren’t exclusive to sailboats, and plenty of motorized recreational craft are starting to take advantage of this style as well. It’s also fairly straightforward to remove the sails and add powered locomotion as well, as this electric catamaran demonstrates.

Not only is this catamaran electric, but it’s solar powered as well. With the mast removed, the solar panels can be fitted to a canopy which provides 600 watts of power as well as shade to both passengers. The solar panels charge two 12V 100ah LifePo4 batteries and run a pair of motors. That’s another benefit of using a sailing cat as an electric boat platform: the rudders can be removed and a pair of motors installed without any additional drilling in the hulls, and the boat can be steered with differential thrust, although this boat also makes allowances for pointing the motors in different directions as well. 

In addition to a highly polished electric drivetrain, the former sailboat adds some creature comforts as well, replacing the trampoline with a pair of seats and adding an electric hoist to raise and lower the canopy. As energy density goes up and costs come down for solar panels, more and more watercraft are taking advantage of this style of propulsion as well. In the past we’ve seen solar kayaks, solar houseboats, and custom-built catamarans (instead of conversions) as well.

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Gene Editing Spiders To Produce Red Fluorescent Silk

May 21, 2025 by 15 Comments
Regular vs gene-edited spider silk with a fluorescent gene added. (Credit: Santiago-Rivera et al. 2025, Angewandte Chemie)
Regular vs gene-edited spider silk with a fluorescent gene added. (Credit: Santiago-Rivera et al. 2025, Angewandte Chemie)

Continuing the scientific theme of adding fluorescent proteins to everything that moves, this time spiders found themselves at the pointy end of the CRISPR-Cas9 injection needle. In a study by researchers at the University of Bayreuth, common house spiders (Parasteatoda tepidariorum) had a gene inserted for a red fluorescent protein in addition to having an existing gene for eye development disabled. This was the first time that spiders have been subjected to this kind of gene-editing study, mostly due to how fiddly they are to handle as well as their genome duplication characteristics.

In the research paper in Angewandte Chemie the methods and results are detailed, with the knock-out approach of the sine oculis (C1) gene being tried first as a proof of concept. The CRISPR solution was injected into the ovaries of female spiders, whose offspring then carried the mutation. With clear deficiencies in eye development observable in this offspring, the researchers moved on to adding the red fluorescent protein gene with another CRISPR solution, which targets the major ampullate gland where the silk is produced.

Ultimately, this research serves to demonstrate that it is possible to not only study spiders in more depth these days using tools like CRISPR-Cas9, but also that it is possible to customize and study spider silk production.

Grid overlayed onto a mason jar. Across the grid are high voltage purple coronas.

High Voltage For Extreme Ozone

May 21, 2025 by 3 Comments

Don’t you hate it when making your DIY X-ray machine you make an uncomfortable amount of ozone gas? No? Well [Hyperspace Pirate] did, which made him come up with an interesting idea. While creating a high voltage supply for his very own X-ray machine, the high voltage corona discharge produced a very large amount of ozone. However, normally ozone is produced using lower voltage, smaller gaps, and large surface areas. Naturally, this led [Hyperspace Pirate] to investigate if a higher voltage method is effective at producing ozone.

Using a custom 150kV converter, [Hyperspace Pirate] was able to test the large gap method compared to the lower voltage method (dielectric barrier discharge). An ammonia reaction with the ozone allowed our space buccaneer to test which method was able to produce more ozone, as well as some variations of the designs.

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[Austin Blake] sitting on line follower cart in garage

Honey, I Blew Up The Line Follower Robot

May 21, 2025 by 5 Comments

Some readers may recall building a line-following robot during their school days. Involving some IR LEDs, perhaps a bit of LEGO, and plenty of trial-and-error, it was fun on a tiny scale. Now imagine that—but rideable. That’s exactly what [Austin Blake] did, scaling up a classroom robotics staple into a full-size vehicle you can actually sit on.

The robot uses a whopping 32 IR sensors to follow a black line across a concrete workshop floor, adjusting its path using a steering motor salvaged from a power wheelchair. An Arduino Mega Pro Mini handles the logic, sending PWM signals to a DIY servo. The chassis consists of a modified Crazy Cart, selected for its absurdly tight turning radius. With each prototype iteration, [Blake] improved sensor precision and motor control, turning a bumpy ride into a smooth glide.

The IR sensor array, which on the palm-sized vehicle consisted of just a handful of components, evolved into a PCB-backed bar nearly 0.5 meters wide. Potentiometer tuning was a fiddly affair, but worth it. Crashes? Sure. But the kind that makes you grin like your teenage self. If it looks like fun, you could either build one yourself, or upgrade a similar LEGO project.
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Field Testing An Antenna, Using A Field

May 21, 2025 by 9 Comments

The ARRL used to have a requirement that any antenna advertised in their publications had to have real-world measurements accompanying it, to back up any claims of extravagant performance. I’m told that nowadays they will accept computer simulations instead, but it remains true that knowing what your antenna does rather than just thinking you know what it does gives you an advantage. I was reminded of this by a recent write-up in which the performance of a mylar sheet as a ground plane was tested at full power with a field strength meter, because about a decade ago I set out to characterise an antenna using real-world measurements and readily available equipment. I was in a sense field testing it, so of course the first step of the process was to find a field. A real one, with cows. Continue reading “Field Testing An Antenna, Using A Field” →