What’s Inside A Super-Cheap Projector? Not A Lot!

December 18, 2022 by Donald Papp 39 Comments

[Raymond Ma] has a penchant for browsing Aliexpress and purchasing curious pieces of hardware that are as high on promises as they are low on cost. This is a process he aptly sums up with his opening line of “I should have known better, but…” Luckily, these devices all get torn down and analyzed so we can each enjoy and share a little slice of disappointment.

One such item is the $30 USD YT200 mini projector, which at 320×180 is almost as low on pixels as it is on cost. Still, [Raymond] looks inside to find out if there is perhaps more hacking potential than there is image resolution.

The YT200 lacks any kind of normal video input, and the anemic 15 lumen output is brazenly branded as a feature to protect children’s eyes from excessive brightness.

Light from the single LED is collimated with some Fresnel lenses. That light passes through an LCD panel, and from there the image bounces off a mirror and through a focusing lens housed in a spiral guide. Focal adjustments are made with a small lever, and the whole assembly provides just enough friction to prevent the lens from moving out of focus on its own.

The device actually does work fairly well for what it is: a way to play a range of different media types off a connected USB storage device. As long as one is in a dark room, anyway.

[Raymond] hopes to find some alternate use for the device. Might we suggest projecting into a frosted glass globe to create a sort of spherical display? A spooky eye animation on a USB stick might pair well with that.

See What You’re In For When Buying And Moving A Lathe

December 11, 2022 by Donald Papp 46 Comments

Sometimes, with patience and luck, one can score a sweet deal on machinery. But for tools that weigh many hundreds of pounds? Buying it is only the beginning of the story. [Ben Katz] recently got a lathe and shared a peek at what was involved in moving a small (but still roughly 800 pound) Clausing 4901 lathe into its new home and getting it operational.

The lathe had sat unused in a basement, but was ready for a new home.

Moving such a stout piece of equipment cannot simply be done by recruiting a few friends and remembering to lift with the legs. This kind of machinery cannot be moved and handled except with the help of other machines, so [Ben] and friends used an engine hoist with a heavy-duty dolly to get it out of the basement it was in, and into the bed of a pickup truck. Separating the lathe from its base helped, as did the fact that the basement had a ground-level egress door which meant no stairs needed to be involved.

One also has to consider the machine’s ultimate destination, because not all floors or locations can handle nearly a thousand pounds of lathe sitting on them. In [Ben]’s case, that also meant avoiding a section of floor with a maintenance trapdoor when moving the lathe into the house. Scouting and knowing these things ahead of time can be the difference between celebratory pizza and deep dish disaster. Pre-move preparation also includes ensuring everything can physically fit through the necessary doorways ahead of time; a task that, if ignored, will eventually explain itself.

With that all sorted out, [Ben] dives into cleaning things up, doing function checks, and in general getting the lathe up and running. He provides some fantastic photos and details of this process, including shots of the 70s-era documentation and part diagrams.

Watch the first chips fly in the short video embedded below. And should you be looking at getting a lathe of your own? Check out our very own buyer’s guide to lathe options.

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DIY Comparatron Helps Trace Tiny, Complex Objects

December 11, 2022 by Donald Papp 21 Comments

Hackers frequently find themselves reverse-engineering or interfacing to existing hardware and devices, and when that interface needs to be a physical one, it really pays to be able to take accurate measurements.

This is easy to do when an object is big enough to fit inside calipers, or at least straight enough to be laid against a ruler. But what does one do when things are complex shapes, or especially small? That’s where [Cameron]’s DIY digital optical comparator comes in, and unlike commercial units it’s entirely within the reach (and budget) of a clever hacker.

The Comparatron is based off a CNC pen plotter, but instead of a pen, it has a USB microscope attached with the help of a 3D-printed fixture. Serving as a background is an LED-illuminated panel, the kind useful for tracing. The physical build instructions are here, but the image should give most mechanically-minded folks a pretty clear idea of how it fits together.

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Fixing (And Improving!) An Annoying Apartment Entry System

December 11, 2022 by Donald Papp 7 Comments

[Zak]’s two-floor apartment has a typical door entry control system, but the setup is less than ideally convenient. The wall-mounted telephone-like intercom is downstairs, but [Zak] is usually upstairs. What’s an enterprising hacker to do? Obviously the most elegant solution is to simply do without visitors in the first place, but [Zak] opted for a more full-featured solution to the problem.

The layout of the typical wall-mounted door intercom is less than ideal.

He fixed things with a custom ESP8285-based board that, with the help of opto-isolation, allows him to detect visitors and grant entry without having to be physically present at the wall-mounted intercom. It’s even integrated into Telegram, and has a few neat new features. Let’s take a look.

The first interesting bit is how [Zak] rolled his own opto-isolation. The door entry system uses 14 VAC and is frankly — electromagnetically-speaking — a very noisy device. Attaching GPIO pins directly to this system from the ESP board for interfacing is not an option. The solution in situations like this is to use opto-isolation, so that interfaced devices can be electrically isolated from one another.

Rather than use off-the-shelf options, [Zak] opted to keep things small and economical by rolling his own solution using side-mounted IR LEDs on the small interface PCB. LEDs can also act as photodiodes, so by pointing two LEDs directly at one another and driving one LED from the door control system and measuring the small amount of resulting current on the other LED, [Zak] can detect states without having to directly connect a GPIO pin.

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Gaze Upon The Swimming Mechanical Stingray, Made With LEGO

December 10, 2022 by Donald Papp 5 Comments

Stingrays have an elegant, undulating swimming motion that can be hypnotic. [Vimal Patel] re-created this harmony with his fantastic mechanical mechanical stingray using LEGO pieces and a LEGO Technics Power Functions motor. The motor is set in a clever arrangement that drives the motion remotely, so that it and electrical elements can stay dry.

The mechanical stingray sits at the end of a sort of rigid umbilical shaft. This shaft connects the moving parts to the electrical elements, which float safely on the surface. This leaves only the stingray itself with its complex linkages free to move in the water, while everything else stays above the waterline.

We’ve seen some impressive LEGO creations before, like this race car simulator and pneumatic engine, and the mechanical action in this stingray is no exception. Interested in making your own? The part list and build directions are available online, and you can see it in action in the video embedded below.

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Old-School Video Switching Levels Up With Modern USB Control

December 10, 2022 by Donald Papp 13 Comments

Video effects and mixing are done digitally today, but it wasn’t always so. When analog ruled the video world, a big switch panel was key to effective results.

VIdeo like this was the result of combining different analog feeds with different effects. The better the hardware, the more was possible.

Devices like [Glen]’s Grass Valley Series 300 Crosspoint Switch Panel were an important part of that world. With tools like that, a human operator could set up a composited preview feed in true WYSIWYG style, and switch to live on cue. All done with relatively simple CMOS ICs and buttons. Lots and lots of buttons.

[Glen] reverse engineers the panel to show how it works, and most of the heavy lifting is done by the MC14051B analog multiplexer/demultiplexer, and the MC14532B 8-bit priority encoder. Once that’s figured out, the door is open to modernizing things a little by using a microcontroller to drive the device, turning it into a USB peripheral.

With a little design work, [Glen] builds a PCB around the EFM8UB2 8-bit microcontroller to act as a USB peripheral and control the switch panel, taking care of things like key scanning and lamp control. The last step: a GUI application for monitoring and controlling the panel over USB.

This isn’t [Glen]’s first time interfacing to vintage video mixing and switching, and as many of us know it’s sometimes tricky work to interface to existing hardware. We covered his earlier video switcher project using hardware that was not nearly as easy to work with as this one.

Flipper Zero Hacker Tool Gets UI Editor For Custom Apps

December 10, 2022 by Donald Papp 12 Comments

[Mikhail] released a handy GUI editor/generator tool for the Flipper Zero multipurpose hacker tool, making layouts and UI elements much easier and more intuitive to craft up.

Those who decide to delve into rolling their own applications or add-ons will find this a handy resource, especially as it generates the necessary code for the visual elements. It’s not limited to placing icons, either. Boxes, lines, dots, text, and more can be freely laid out to get things looking just right.

To use it, simply drag and drop icons of various sizes into the screen area. Non-icon UI elements like frames, lines, text, and others can be placed with a click using the buttons. To move elements around, click the SELECT button first, then drag things as needed. To fine-tune positioning (or change the text of a string) a selected element’s properties can be accessed and modified to the right of the simulated screen. When things look good, switch to the CODE tab and copy away to use it in your Flipper application.

Unfamiliar with the Flipper Zero? It’s a kind of wireless multitool; a deeply interesting device intended to make wireless exploration and experimentation as accessible as its dolphin mascot is adorable.