Optimizing A QuickTake Image Decoder For The Apple II’s 6502

October 5, 2025 by Maya Posch 7 Comments

The idea of using the Apple II home computer for digital photography purposes may seem somewhat daft considering that this is not a purpose that they were ever designed for, yet this is the goal that [Colin Leroy-Mira] had, requiring some image decoder optimizations. That said, it’s less crazy than one might assume at first glance, considering that the Apple II was manufactured until 1993, while the Apple QuickTake digital cameras that [Colin] wanted to use for his nefarious purposes saw their first release in 1994.

These QuickTake cameras feature an astounding image resolution of up to 640×480, using 24-bit color. Using the official QuickTake software for Apple Macintosh System 7 through 9 the photographs in proprietary QTK format could be fetched for display and processing. Doing the same on an Apple II would obviously require a bit more work, not to mention adapting of the image to the limitations of the 8-bit Apple II compared to the Motorola 68K and PowerPC-based Macs that the QuickTake was designed to be used with.

Targeting the typical ~1 MHz 6502 CPU in an Apple II, the dcraw QTK decoder formed the basis for an initial decoder. Many memory and buffer optimizations later, an early conversion to monochrome and various other tweaks later – including a conversion to 6502 ASM for speed reasons – the decoder as it stands today manages to decode and render a QTK image in about a minute, compared to well over an hour previously.

Considering how anemic the Apple II is compared to even a budget Macintosh Classic II system, it’s amazing that displaying bitmap images works at all, though [Colin] reckons that more optimizations are possible.

Wearable Neon Necklaces Run On Battery Power

October 5, 2025 by Lewin Day 22 Comments

We typically think of neon signs as big commercial advertisements, hanging inside windows and lofted on tall signposts outside highway-adjacent businesses. [James Akers] has gone the other route with a fashionable build, creating little wearable neon necklaces that glow beautifully in just the same way.

Aiming for small scale, [James] began with 6 mm blue phosphor glass tube, which was formed to reference Pink Pony Club, one of Chappell Roan’s more popular songs. The glass was then filled with pure neon up to a relatively low pressure of just 8 torr. This was an intentional choice to create a more conductive lamp that would be easier to run off a battery supply. The use of pure neon also made the tubes easy to repair in the event they had a leak and needed a refill. A Midget Script gas tube power supply is used to drive the tiny tubes from DC power. In testing, the tubes draw just 0.78 amps at 11.8 volts. It’s not a light current draw, but for neon, it’s pretty good—and you could easily carry a battery pack to run it for an hour or three without issue.

If you’re not a glass blower, fear not—you can always make stuff that has a similar visual effect with some LEDs and creativity. Meanwhile, if you’ve got your own neon creations on the go—perhaps for Halloween?—don’t hesitate to light up the tipsline!

3D Printing A New Kind Of Skateboard That Is Ultimately Unsafe

October 5, 2025 by Lewin Day 12 Comments

Skateboards were organically developed in the 1940s and 1950s; 30 years would then pass before the ollie was developed, unlocking new realms for skaters dedicated to the artform. The advent of powerful batteries and motors would later make the electric skateboard a practical and (un?)fashionable method of transport in more recent years. Now, [Ivan Miranda] is pushing the cutting edge of skateboarding even further, with an entirely weird build of his own design.

The build was inspired by one-wheels, which [Ivan] considers fun but ultimately too dangerous. Most specifically, he fears crashing when the one-wheel is tilted beyond a critical angle at which the motor can restore it to a level heading. His concept was to thus create a two-wheeled board that is nonetheless controlled with the leaning interface of a one-wheel.

The frame is assembled from a combination of 3D-printed brackets and aluminium extrusion. The rider stands on a platform which rides on rollers on top of the frame, tilting it to control the drive direction of the board. Detecting the angle is handled by an Arduino Due with an MPU6050 IMU onboard. The microcontroller is then responsible for commanding the speed controller to move the board. Drive is from a brushless DC motor, hooked up to one of the wheels via a toothed belt. Power is courtesy of three power tool batteries.

Early testing showed the design to be a bit of a death trap. However, with refinement to the control system code and an improved battery setup, it became slightly more graceful to ride. [Ivan] notes that more tuning and refinement is needed to make the thing safer than a one-wheel, which was the original goal. We’ve seen some other great builds from [Ivan] before, too. Video after the break.

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Simple Counter Mechanism In An Asthma Inhaler

October 5, 2025 by Maya Posch 9 Comments

The counter wheel and white worm gear inside the counter. (Credit: Anthony Francis-Jones, YouTube)

Recently [Anthony Francis-Jones] decided to take a closer look at the inhaler that his son got prescribed for some mild breathing issues, specifically to teardown the mechanical counter on it. Commonly used with COPD conditions as well as asthma, these inhalers are designed to provide the person using it with an exact dose of medication that helps to relax the muscles of the airways. Considering the somewhat crucial nature of this in the case of extreme forms of COPD, the mechanical counter that existed on older versions of these inhalers is very helpful to know how many doses you have left.

Disassembling the inhaler is very easy, with the counter section easily extracted and further disassembled. The mechanism is both ingenious and simple, featuring the counter wheel that’s driven by a worm gear, itself engaged by a ratcheting mechanism that’s progressed every time the cylinder with the medication is pushed down against a metal spring.

After the counter wheel hits the 0 mark, a plastic tab prevents it from spinning any further, so that you know for certain that the medication has run out. In the video [Anthony] speculates that the newer, counter-less inhalers that they got with the latest prescription can perhaps be harvested for their medication cylinder to refill the old inhaler, followed by resetting the mechanical counter. Of course, this should absolutely not be taken as medical advice.

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2025 Component Abuse Challenge: Digital Logic With Analog Components

October 4, 2025 by Bryan Cockfield 10 Comments

[Tim] noticed recently that a large number of projects recreating discrete logic tend to do so with technology around 70 years old like resistor-transistor logic (RTL) or diode-transistor logic (DTL). To build something with these logic families nowadays requires an intense treasure hunt of antique components bordering on impossible and/or expensive. Rather than going down this rabbit hole he decided to invent a somewhat new logic system using analog components in this entry in our Component Abuse Challenge.

The component in question here is an analog multiplexer, which is normally used to select one of two (or several) signal lines and pass them through to an output. Unlike digital multiplexers which only pass 1s and 0s, analog multiplexers can pass analog signals since the transistors aren’t driven to saturation. He has come up with an entire system of logic gates using these components, with trickier devices like latches eventually implemented with help from a capacitor.

The first attempt at using this logic system had a small mistake in it which caused these latches to behave as oscillators instead, due to a polarity mistake. But a second attempt with simplified design and reduced component count ended up working, proving out [Tim]’s concept. Not only that but his second prototype is functioning at an impressive 15 MHz, with a possibility of an even higher clock speed in future designs. Not bad!

How To Design Custom LCDs For Your Own Projects

October 4, 2025 by Lewin Day 7 Comments

These days, you can buy full graphical LCD or OLED displays for just a few dollars. However, if you’re so inclined, you can actually get your own segmented LCDs made to suit your own projects. [Icoso Labs] explains how it’s done, with plenty of handy tips along the way.

There are three primary things you need to do to design a segmented LCD. First, you need to design it visually, laying out all the individual elements you want on the display. Then you need to determine how you want to split them up into segments. Some elements you’ll just want to be a single monolithic on-or-off shape, while other areas you might want to create things like seven-segment numerals for displaying numbers and so on. With that done, you also need to specify various engineering details—such as whether you want a transmissive, reflective, or transflective display, and thicknesses, colors, and other important things. Armed with all that, you can take your design to a manufacturer and get them to make a bunch for you. Often, there’s a moderately high tooling cost to start a run, but you can then turn out more examples of your design for just a few bucks apiece.

It’s a neat guide to designing something few of us have ever considered sourcing for ourselves. We’ve featured other insights into the world of segmented LCDs before, too. Video after the break.

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Open Source Controller For Old And Expensive Industrial Robots

October 4, 2025 by Maya Posch 16 Comments

The Zynq-7000 usage at the core of the robot controller. (Credit: Excessive Overkill, YouTube)

Industrial robots like robotic arms are basically everywhere, albeit usually out of the public’s eye in factories. This also means that they get replaced and scrapped all the time, making for many opportunities to snap up an industrial robot that once cost as much as a pretty fancy car for essentially peanuts. Over the years the bloke behind the [Excessive Overkill] YouTube channel did this a lot, which also revealed the main issue with these ‘cheap’ robots: the electronics and associated software, with the manufacturer rarely going out of their way to appease to hobbyists trying to fix up one of these units, never mind for free.

That said, if you’re persistent enough, you can reverse-engineer these beasts to the point where you can develop your own controller hardware and software solution. This is exactly what was done, resulting in an open source controller, found on the ExcessiveMotion GitHub page, that should allow you to control many of these industrial robots. At the core is a Zynq-7000 hybrid FPGA-ARM SoC chip, running real-time Linux (with preemptive scheduling patch) on the SoC side and custom HDL on the FPGA side to handle the hard real-time tasks.

The controller during testing. (Credit: Excessive Overkill, YouTube)

The controller is made to be modular, with a backplane that can accept various interface cards in addition to the current RS-485 and RS-422 interfaces that are commonly used in industrial settings, such as here for controlling the individual servo drives of the robots. To make assembly and testing interesting, the first controller and integration with a robot was made ready for display at the Open Sauce 2025 event, requiring things to be rushed along, including reverse-engineering the servo protocol for a small-ish industrial robot suitable for public display and use, as well as developing the kinematics for the robotic arm.

With the controller now demonstrated, clearly this is the perfect time to rush out and get one of these fun industrial robots for a few hundred bucks. Currently the controller is still being finalized, with the author asking for feedback on what it should be able to support. If you have a particularly unusual industrial robot lounging around without the requisite controller, this might be your chance to revive it.

Thanks to [Hans] for the tip.

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