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 8 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 6 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 13 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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3D Printing A Cheap VR Headset

October 4, 2025 by Lewin Day 22 Comments

The modern era of virtual reality really kicked off in earnest just over a decade ago, when the Oculus Rift promised 3D worlds beyond your wildest dreams. Since then, nobody’s been able to come up with a killer app to convince even a mild fraction of consumers to engage with the technology. Still, if you’re keen to tinker, you might like to make your own headset like [CNCDan] has done.

The build is based almost entirely on 3D-printed components and parts sourced from AliExpress. It offers 2880x1440p resolution, thanks to a pair of square 1440×1440 LCD displays, one for each eye, paired with a couple of 34 mm lenses. The headset has adjustable interpupiliary distance so you can dial the view in to properly suit your eyes. The 3D-printed housing is designed to be compatible with headrest pads from the HTC Vive Pro for comfort’s sake. Head tracking is also available, with the inclusion of an IMU and an Arduino onboard. [CNCDan] apparently put the build together for under $150, which is not bad compared to the price of a commercial off-the-shelf unit. Files are on Github for the curious.

[CNCDan] reports good results with the DIY headset, using it primarily with his racing simulator setup. He has had some issues, however, with his LCD screens, which don’t properly run at a 90 Hz refresh rate at full resolution, which is frustrating. It’s an issue he’s still looking into. We’ve seen some other neat VR builds over the years, too. Video after the break.

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Serial And UPDI Handled Together With One Convenient Circuit

October 4, 2025 by Lewin Day 7 Comments

Sometimes it’s nice when you can do everything you need to do with just one single port. In this vein, [Nicola Strappazzon] whipped up a circuit to combine serial and UPDI programming in a very convenient way.

As an example, [Nicola] demonstrates the concept using an AVR128DA28 microcontroller. It’s paired with a 4052 multiplexer IC and a CH340 USB-to-serial chip. Everything is wired up such that the 4052 acts as a switch for the signal coming from the CH340. When the RTS flow-control signal is set high, it switches the 4052 to hook up the CH340’s RX and TX pins to the UDPI interface on the AVR microcontroller. Conversely, when the RTS signal is set low, the CH340 is instead hooked up to the serial UART on the microcontroller. From there, it’s a simple matter of configuring avrdude to properly set the RTS pin when attempting to program the attached device.

If you’re working with UPDI devices and you want to be able to talk to them and program them with a minimum of fuss, this project might be useful for you. We’ve looked at dedicated UPDI programmers before, too. If you’re cooking up your own nifty microcontroller hacks, don’t hesitate to let us know on the tipsline.

How Do The Normal People Survive?

October 4, 2025 by Elliot Williams 112 Comments

It was one of those weeks last week at Hackaday’s home office. My mother-in-law handed me her favorite power bank and said “it’s not charging”. She had every expectation that I’ll open it up, desolder the weary pouch inside, scrounge a LiPo out of some corner of the basement, and have it back up and running before the weekend. And of course that’s what happened, although maybe it looks a little worse for wear because it was hard to open the sealed case without excessive force. Sorry about that!

Then on the weekend, I finally got fed up with the decomposing foam on the face seal on my FPV goggles. It was leaking light all over the place. Of course I could have bought a new seal, but then I’d have to wait a week or so for delivery. So I pulled the velcro backing off, tossed it in the bed scanner, pulled the image up in Inkscape, converted it to Gcode, and cut out a couple seals out of EVA foam on the laser. Not only are they essentially indestructible, but I was able to customize them a little bit, and the fit is now better than ever.

And then, one of our neighbors bought a new garage door fob, flipped the DIP switches into the right configuration, and couldn’t figure out why it wouldn’t open the garage door. Knock knock knock. Using the tried-and-true RF probe that everyone with a scope probe has sitting around, namely hooking the ground pin to the tip and putting the radio device in the loop, it was clear that the sense of the DIP switches was inverted from what it said in the instructions. That was a fun little puzzle.

It was the garage door opener that triggered me to think about how normal people would handle any of these situations. “How do the normies even get by?” were the exact words that went through my head. And let’s face it: we’re not entirely normal. Normal people don’t have a soldering setup just sitting around ready to get hot 24/7, or a scope to diagnose a garage door RF transmitter at the drop of a hat. But these things seem to happen to me all the time. How do the normal people survive? Maybe they all know someone with a scope?

I take it as my service to the world to be “that guy” for most of our friends and family, and I pretty much do it without complaint. “With great power” and all that. My wife is just about as gracious when she’s stuck debugging a parent’s Windows setup, so I’m not saying I’m the only saint in the world, either. Surely you have similar stories.

But last week it made me reflect on how good we’ve got it, and that does make me want to pay it forward a little bit. If you’re one of the people who can, try to help out those who can’t.