Diagram showing the structure of the base.

Magic On Your Desk Via MagLev Toy

May 7, 2025 by 9 Comments

Magnets aren’t magic, but sometimes you can do things with them to fool the uninitiated — like levitating. [Jonathan Lock] does that with his new maglev desk toy, that looks like at least a level 2 enchantment.

This levitator is USB-powered, and typically draws 1 W to 3 W to levitate masses between 10 g and 500 g. The base can provide 3 V to 5 V inductive power to the levitator to the tune of 10 mA to 50 mA, which is enough for some interesting possibilities, starting with the lights and motors [Jonathan] has tried.

In construction it is much like the commercial units you’ve seen: four permanent magnets that repel another magnet in the levitator. Since such an arrangement is about as stable as balancing a basketball on a piece of spaghetti, the permanent magnets are wrapped in control coils that pull the levitator back to the center on a 1 kHz loop. This is accomplished by way of a hall sensor and an STM32 microcontroller running a PID loop. The custom PCB also has an onboard ESP32, but it’s used as a very overpowered USB/UART converter to talk to the STM32 for tuning in the current firmware.

If you think one of these would be nice to have on your desk, check it out on [Jonathan]’s GitLab. It’s all there, from a detailed build guide (with easy-to-follow animated GIF instructions) to CAD files and firmware. Kudos to [Jonathan] for the quality write-up; sometimes documenting is the hardest part of a project, and it’s worth acknowledging that as well as the technical aspects.

We’ve written about magnetic levitation before, but it doesn’t always go as well as this project. Other times, it very much does. There are also other ways to accomplish the same feat, some of which can lift quite a bit more.

Tracking The Sun? Nah!

May 7, 2025 by 43 Comments

If you want solar power, you usually have to make a choice. You can put a solar panel in a fixed location and accept that it will only put out the maximum when the sun is properly positioned. Or, you can make the panels move to track the sun.

While this isn’t difficult, it does add cost and complexity, plus mechanical systems usually need more maintenance. According to [Xavier Derdenback], now that solar panels are cheaper than ever, it is a waste of money to make a tracking array. Instead, you can build a system that looks to the east and the west. The math says it is more cost effective.

The idea is simple. If you have panels facing each direction, then one side will do better than the other side in the morning. The post points out that a tracking setup, of course, will produce more power. That’s not the argument. However, for a given power output, the east-west solution has lower installation costs and uses less land.

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Adorable Robot Steals The Show

May 6, 2025 by 12 Comments

An ongoing refrain with modern movies is “Why is all of this CG?”– sometimes, it seems like practical effects are simultaneously a dying art, while at the same time modern technology lets them rise to new hights. [Davis Dewitt] proves that second statement with his RC movie star “robot” for an upcoming feature film.

The video takes us through the design process, including what it’s like to work with studio concept artists. As for the robot, it’s controlled by an Arduino Nano, lots of servos, and a COTS airplane R/C controller, all powered by li-po batteries. This is inside an artfully weathered and painted 3D printed body. Apparently weathering is important to make the character look like a well-loved ‘good guy’. (Shiny is evil, who knew?) Hats off to [Davis] for replicating that weathering for an identical ‘stunt double’.

Check out the video below for all the deets, or you can watch to see if “The Lightning Code” is coming to a theater near you. If you’re into films, this isn’t the first hack [Davis] has made for the silver screen. If you prefer “real” hacks to props, his Soviet-Era Nixie clock would look great on any desk. Thanks to [Davis] for letting us know about this project via the tips line.

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DIY Penicillin

May 6, 2025 by 21 Comments

We don’t often consider using do-it-yourself projects as a hedge against the apocalypse. But [The Thought Emporium] thinks we should know how to make penicillin just in case. We aren’t so sure, but we do think it is a cool science experiment, and you can learn how to replicate it in the video below.

If you want to skip the history lesson, you need to fast-forward to about the six-minute mark. According to the video, we are surrounded by mold that can create anti-bacterial compounds. However, in this case, he starts with a special strain of mold made to produce lots of antibiotics.

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Five Oddest Op Amp Applications

May 6, 2025 by 25 Comments

You think of op amps as amplifiers because, no kidding, it is right in the name. But just like some people say, “you could do that with a 555,” [Doctor Volt] might say, “you can do that with an op amp.” In a recent video, you can see below, he looks at simulations and breadboards for five applications that aren’t traditional amplifiers.

Of course, you can split hairs. A comparator is sort of an amplifier with some very specific parameters, but it isn’t an amplifier in the classic sense.

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A New, Smarter Universal Remote

May 6, 2025 by 21 Comments

The remote for [Dillan Stock]’s TV broke, so he built a remote. Not just as a replacement but as something new. For some of us, there was a glorious time in the early 2000s when a smart remote was needed and there were options you could buy off the shelf. Just one handy button next to the screen had a macro programmed that would turn on the receiver, DVD player, and TV, and then configure it with the right inputs. However, the march of technological convenience has continued and nowadays soundbars turn on just in time and the TV auto switches the input. Many devices are (for better or worse) connected to WiFi, allowing all sorts of automation.

[Dillan] was lucky enough that his devices were connected to his home assistant setup. So this remote is an ESP32 running ESPHome. These automations could be triggered by your phone or via voice assistant. What is more interesting is watching [Dillan] go through the design process. Deciding what buttons there should be, where they should be placed, and how the case would snap together takes real effort. The design uses all through-hole components except for the ESP32 which is a module.

This isn’t the first thing [Dillan] has made with an ESP32, as he previously revamped a non-standard smart lamp with the versatile dev board. The 3d printable files for the remote are free available. Video after the break.

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Building A DIY Chicken Incubator

May 6, 2025 by 16 Comments

If you want to keep eggs warm to hatch, you’ll need an incubator. You could buy one off the shelf, but they’re not so complex — just a nicely-controlled warm box you could easily whip up yourself. As it turns out, that’s precisely what [RCLifeOn] did. 

The incubator is built out of wooden panels screwed together to make a simple box. The frame of the front door is also wood, but it features 3D printed hinges and handles, because that’s the easiest way to make hardware when you’re a printing wizard like [RCLifeOn].

The box is fitted with controls for humidity and temperature to ensure the best possible conditions for hatching chicken eggs inside. As you might have guessed, a heated bed from a 3D printer was used to control the temperature inside. As for humidity, a sensor tracks the conditions in the box, and triggers an ultrasonic mister to increase the level as necessary. There’s also a little motion introduced via a moving platform run by a motor and some step-down gearing, which apparently aids in the hatching process.

[RCLifeOn] calls it “a machine that creates life,” and that honestly sounds about fair. We’ve seen similar projects along these lines before, too.

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