Author: Lewin Day

3557 Articles

3D Printed Robot Arm Built For Learning Purposes

March 24, 2026 by No comments

If you want to work with robots you can do all sorts of learning with software and simulation, but nothing quite beats getting to grips with real machinery. That was the motivation for [James Gullberg] to build this impressive robot arm. 

Featuring six degrees of freedom, the robot arm is mostly constructed of 3D printed components. This let [James] experiment with a wide variety of joint and reducer designs for the sake of learning and investigation. The base of the robot uses a fairly conventional planetary gear drive, while shoulder and elbow joints rely on split-ring planetary gearboxes to allow for high torque density with regards to size. [James] implemented a neat sensing technique here, integrating alternating magnets into the output ring gear which are monitored via a magnetic encoder. The wrist joint switches things up again, running via an inverted belt differential.

Running the show is an STM32 microcontroller, which talks to all the encoders, communicates with a Raspberry Pi over CAN bus, and handles all the necessary PID control loops and step generation for the drive motors. The plan is to run higher-level control on the Raspberry Pi which will run a ROS 2-based software stack. Already, the various joints look smooth and impressive in motion.

If you’re looking to learn about robot arms, you really can’t beat building one. We’ve featured a few projects along these lines before. Most of them aren’t exactly production-line ready, but they will teach you a ton about control, motion planning, and all sorts of associated skills. That experience can be invaluable if you intend to work with robots in industry.

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Building A Monitor Light Bar For Better Productivity

March 24, 2026 by 6 Comments

If you’re intending to work at your desk for long periods of time, good lighting is a must, as it can help stave off eye strain and mental fatigue. It was a desire for more comfortable productivity that drove [Jade] to whip up a monitor-mounted lighting system for her workstation.

The build uses an ESP32 to run the show, with a rotary encoder for manual control and firmware that allows the monitor light to be neatly integrated with Home Assistant. The light itself comes from light strips that feature both warm white and cold white LEDs. Simple MOSFETs are used to control the brightness of the LEDs and which of the warm and cold LEDs are activated at any time. Everything is wrapped up in a 3D printed housing that neatly sits on top of the monitor with the aid of a simple printed clamp. The LED strips also have a nice soft glow thanks to a strip of diffuser material that [Jade] snatched from an old television.

We love a good lighting build, from the work-focused to the creative and beautiful.

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From Zip To Nought: The Rise And Fall Of Iomega

March 24, 2026 by 52 Comments

If you were anywhere near a computer in the mid-to-late 1990s, you almost certainly encountered a Zip drive. That distinctive purple peripheral, with its satisfying clunk as you slotted in a cartridge, was as much a fixture of the era as beige tower cases and CRT monitors. Iomega, the company behind it, went from an obscure Utah outfit to a multi-billion-dollar darling of Wall Street in the span of about two years. And then, almost as quickly, it all fell apart.

The story of Iomega is one of genuine engineering innovation and the fickle nature of consumer technology. As with so many other juggernauts of its era, Iomega was eventually brought down by a new technology that simply wasn’t practical to counter.

The House That Bernoulli Built

Iomega was founded in Utah, in 1980, by Jerome Paul Johnson, David Bailey, and David Norton. The company soon developed a novel approach to removable magnetic storage based on the Bernoulli effect. The Bernoulli Box arrived in 1982, which was a drive relying on PET film disks spun at 1500 RPM inside a rigid, removable cartridge. The airflow generated by the spinning disk pulled the media down toward the read/write head thanks to the eponymous Bernoulli effect. While spinning, the disk would float a mere micron above the head surface on a cushion of air. If the power cut out or the drive otherwise failed, the disk simply floated away from the head rather than crashing into it—a boon over contemporary hard drives for which head crashes were a real risk. The Bernoulli Box made them essentially impossible. Continue reading “From Zip To Nought: The Rise And Fall Of Iomega” →

Disposable Vape Becomes Breath-Activated Synth

March 24, 2026 by 8 Comments

Makers and hardware hackers have been collecting disposable vapes for some time now, usually to salvage their batteries or the unique displays many models now come with. But you can also repurpose them for other ends, such as playing music. [Becky Stern]’s vape synth is a perfect example of this.

The build started with an ElfBars BC5000 vape. [Becky] notes there may be similar models under different names out there that would work just as well. The vape is effectively gutted for parts, with the LiPo cell, USB charging board, and the low-pressure sensor the main things that remain. These parts are combined with a drop-in 555 synthesizer circuit complete with speaker, which has its pitch controlled by a series of six photoresistors. When the low pressure sensor is triggered by inhalation, the 555 circuit is triggered, and operates at a pitch depending on the resistance of the photoresistor stack.

The output of the vape synth is kind of shrill, and frankly a little bit annoying — which is somehow rather fitting for what it is. If you want to make a better-sounding synth at home, we’ve featured such projects, you’re just unlikely to fit them entirely within the housing of a disposable vape.

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Build This Open-Source Graphics Calculator

March 23, 2026 by 21 Comments

Graphics calculators are one of those strange technological cul-de-sacs. They rely on outdated technology and should not be nearly as expensive as they are, but market effects somehow keep prices well over $100 to this day. Given that fact, you might like to check out an open-source solution instead.

NumOS comes to us from [El-EnderJ]. It’s a scientific and graphic calculator system built to run on the ESP32-S3 with an ILI9341 screen. It’s intended to rival calculators like the Casio fx-991EX ClassWiz and the TI-84 Plus CE in terms of functionality. To that end, it has a full computer algebra system and a custom math engine to do all the heavy lifting a graphic calculator is expected to do, like symbolic differentiation and integration. It also has a Natural V.P.A.M-like display—if you’re unfamiliar with Casio’s terminology, it basically means things like fractions and integrals are rendered as you’d write them on paper rather than in uglier simplified symbology.

If you’ve ever wanted a graphics calculator that you could really tinker with down to the nuts and bolts, this is probably a great place to start. With that said, don’t expect your local school or university to let you take this thing into an exam hall. They’re pretty strict on that kind of thing these days.

We’ve seen some neat hacks on graphics calculators before, like this TI-83 running CircuitPython. If you’re doing your own magic with these mathematical machines, don’t hesitate to notify the tips line.

Stream Deck Radio Controller Built With Cheap Yellow Display

March 23, 2026 by 4 Comments

Stream decks are pretty useful in all kinds of contexts, but commercial models can feel a bit pricy for what is effectively a bunch of buttons. [WhiskeyTangoHotel] has whipped up one of their own on the cheap using some readily available parts.

The build came about due to the use of Stream Decks as a common way to control the Flex-6400 software-defined radio. [WhiskeyTangoHotel] figured that using a full-priced Elgato Stream Deck was overkill for this purpose, and that a cheaper interface could be put together for less. Enter the Cheap Yellow Display—a combination of the ESP32 microcontroller with a 2.8-inch touchscreen LCD. It was simple enough to code the device such that it had four big touch buttons to control RIT-, RIT+, XIT-, and XIT+ on the Flex-6400. Plus, with the ESP32 having WiFi onboard, it’s able to control the radio wirelessly—you just need to feed the unit 5 volts, and you’re up and running.

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Better Faux-Analog VU Meters

March 23, 2026 by 3 Comments

One of the coolest things about old hi-fi hardware is that it often came with flickety needles that danced with the audio level. You can still buy these if you want, or you can simulate the same look on a screen, as [mircemk] demonstrates.

It isn’t [mircemk]’s first rodeo in this regard. An earlier project involved creating simulated VU meters on round displays, but they were somewhat limited. Using the Adafruit GFX library on an ESP32 netted a working setup, but it was jerky and very jagged and digital-looking. It was more akin to a fake needle display running on an 8-bit computer than something that looked like a real vintage VU meter.

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