Not Can It Run DOOM, But Can DOOM Run It?

It’s the standard test for a hardware hack, half serious half in jest, “Can it run DOOM?”. The iconic early-90s shooter from id software has made an appearance on everything from toothbrushes to LEGO bricks, but nobody has yet posed the opposite question: Can DOOM run it?“. It’s one answered by [Danny Spencer], who has proved that it’s possible to perform computational tasks in the game by producing a working adding machine in a DOOM level.

If you’re familiar with the folks who build working computers within Minecraft, this is in a similar vein. Game elements are used to create logic elements, and from there more complex systems can be assembled. DOOM doesn’t have the in-game logic that Minecraft has, but by clever combination of monster behaviour with in-game actions involving rooms, buttons, and doors, it’s possible to create the simplest of building blocks, the NAND gate.

The video below the break shows the adder in action, first in operation (we like the monster-driven display!), and then a tour of the logic area with its rooms full of computational monsters. It’s important to note that this isn’t a computer, he hasn’t proved it as Turing complete, and that the maximum size of a DOOM level whatever it is will impose an upper limit on what can be done. But it does show that in theory at least a computer can be made in DOOM, and we’re sure people will continue this work.

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Drone Rescue Uses VHS Tape And Careful Planning

If you regularly fly your drones outdoors, you’ve probably worried about getting your pride and joy stuck in a big tree at some point. But flying indoors doesn’t guarantee you’ll be safe either, as [Scott Williamson] found out. He once got his tiny 65 mm Mobula 6HD quadcopter stuck in a roof beam at an indoor sports complex, and had to set about a daring rescue.

The first job was recon, with [Scott] sending up another drone to survey the situation. From there, he set about trying to prod the stuck quadcopter free with a improvised lance fitted to the front of a larger drone. But this ended up simply getting the larger bird stuck as well. It eventually managed to free itself, though it was damaged severely when [Scott] caught it as it fell. As told to Hackaday, [Scott] thus decided he needed to build a mock-up of the situation at home, to help him devise a rescue technique.

In the end, [Scott] settled on a grappling hook made of paperclips. A drone lofted a long length of VHS tape over the roof beam, and he then attached the grappling hook from ground level. The VHS tape was then used to reel the hook up to the rafters, and snare the drone, bringing it back down to Earth.

It took some perseverance, but [Scott] ended up rescuing his tiny drone from its lofty prison. The part we love most about this story, though, is that [Scott] planned the recovery like a heist or a cave rescue operation.

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Hackaday Podcast 198: Major Tom On The ISS, 3DP Ovals And Overhangs, Inside A Mini Cheetah Clone

As we slide into the Christmas break, Editor-in-Chief Elliot Williams and Staff Writer Dan Maloney look at the best and brightest of this week’s hacks. It wasn’t an easy task — so much good stuff to choose from! But they figured it out, and talked about everything from impossible (and semi-fractal) 3D printing overhangs and the unfortunate fishies of Berlin’s ex-aquarium, to rolling your own FM radio station and how a spinning Dorito of doom is a confusing way to make an electric vehicle better.

Think it’s no fun when your friend forgets to pick you up at the airport? Wait until you hear about what it’s like to get stuck on the ISS, and the incredibly risky way you might have to get home. Interested in the anatomy and physiology of a cloned robo-dog? Then let the master do a teardown and give you his insight. We’ll make some time for tea, cross our eyes for stereo photos, and dive into the mechanics of the USB-C.

Download the podcast and put it on a minidisc for the reindeer.

Check out the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

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Morphing Keyboard Gets You Dialed In Just Right

So you’re tired of rectangular, brick wall-staggered keyboards and want to go split and/or ergo. But how? Which style? What do? Here’s what you do: you build one of these here LHM Morph boards and customize the crap out of it, because that’s what it’s for.

So what is this thing, anyway? Is it a even a keyboard? Well, as long as you can press switches and send key commands to a computer, it certainly smells like a keyboard to us. Now that we’ve gotten that out of the way, what’s going on here is that [LifeHackerMax] has built a highly-customizable version of the LHM, their 26-key split. The LHM Morph can be fine-tuned to nearly any degree imaginable, including the tenting angle. The keys are grouped in modules that can slide back and forth to suit your varying finger lengths. As they are half-round, these modules can also be tilted and rotated until they’re just right.

But the super cool thing about the LHM Morph is the way it goes together — like LEGO. It’s completely modular, and you don’t even have to go split if you’re not ready for that. But all the pieces connect via rods made of copper wire. If you’d like to make one for yourself, the 3D files are up on Thingiverse, and the firmware is on GitHub. Be sure to check out the video after the break.

Does this keyboard remind you of anything? [Peter Lyons]’ Squeezebox, perhaps?

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A toy gamepad controlling Super Mario World emulated on a MacBook

Turning A Toy Gamepad Into A Real One, With Bluetooth

It’s important to instill healthy habits in your children when they’re still young. Preferences for sports, snacks and dinosaurs are typically formed in early childhood, as is loyalty to a specific gaming platform. [RetrogradeScene] apparently wished to steer his young daughter towards the Nintendo camp, but wasn’t looking forward to having her grubby hands touch his prized controllers. So he built her her own kid-friendly controller out of a Fisher-Price toy.

The toy in question is an imitation game controller that just makes funny sounds when you press the buttons. Converting it into a real, working game controller was a matter of soldering some wires onto the existing PCB and hooking them up to a microcontroller board, in this case a DFRobot FireBeetle. After loading the ESP32-BLE-Gamepad library and assigning the correct pin-button combinations in software [RetrogradeScene] ended up with a big, brightly-coloured gamepad that actually functioned as one.

Unfortunately, the FireBeetle took up space where the original AAA batteries were sitting, so the hacked gamepad needed a new power source. Classic batteries are heavy and inconvenient anyway, so [RetrogradeScene] installed a modern lithium battery plus a USB-C port for charging. Of course, no Bluetooth gadget is complete without an accompanying smartphone app either: [RetrogradeScene] wrote one for his iPhone that enables him to quickly change the button layout between the Nintendo and Xbox styles.

This might be a rare example of someone making a gamepad from, well, a gamepad. We’ve seen a few more unusual things being converted into game controllers, ranging from a handful of LEGO bricks to entire cars.

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Restarting The Grid When The Grid Is Off The Grid

If you watch YouTube long enough, it seems like going “off the grid” is all the rage these days. But what if the thing that goes off the grid is the grid itself? In the video below the break, [Grady] with Practical Engineering explores the question: How do you restart an entire power grid after it’s gone offline? It’s a brilliantly simple deep dive into what it takes to restore power to large amounts of customers without causing major damage to not just the grid, but the power generators themselves.

What’s A Power Grid Operators Favorite Band?

The hackers among us who’ve dealt with automotive alternators know it must be excited in order to generate electricity. What does that even mean, and how does it affect the grid? Simply put, it takes power to make power. For example, old heavy equipment had what they called pony motors — a small easy to start engine that’s sole purpose was to start a much larger engine. Aircraft have auxiliary power units (APUs) for the same purpose. What do power grids have? You’ll have to watch the video to find out.

Once at least two power generators are online, grid operators can just flip the switch and start feeding power to customers, right? Not quite. [Grady] once again uses a clever test jig and an oscilloscope to show the damage that can occur if things aren’t done just right. It’s a fascinating video well worth watching.

Learn how grid operators use a Power Grid Emulator called LEGOS to help them with keeping the electrons flowing in the right direction.

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3D Printed ROV Is The Result Of Many Lessons Learned

Building an underwater remotely operated vehicle (ROV) is always a challenge, and making it waterproof is often a major hurdle. [Filip Buława] and [Piotr Domanowski] have spent four years and 14 prototypes iterating to create the CPS 5, a 3D printed ROV that can potentially reach a depth of 85 m.

FDM 3D prints are notoriously difficult to waterproof, thanks to all the microscopic holes between the layers. There are ways to mitigate this, but they all have limits. Instead of trying to make the printed exterior of the CPS 5 waterproof, the electronics and camera are housed in a pair of sealed acrylic tubes. The end caps are still 3D printed, but are effectively just thin-walled containers filled with epoxy resin. Passages for wiring are also sealed with epoxy, but [Filip] and [Piotr] learned the hard way that insulated wire can also act as a tube for water to ingress. They solved the problem by adding an open solder joint for each wire in the epoxy-filled passages.

For propulsion, attitude, and depth control, the CPS 5 has five brushless drone motors with 3D printed propellers, which are inherently unaffected by water as long as you seal the connectors. The control electronics consist of a PixHawk flight controller and a Raspberry Pi 4 for handling communication and the video stream to a laptop. An IMU and water pressure sensor also enable auto-leveling and depth hold underwater. Like most ROVs, it uses a tether for communication, which in this case is an Ethernet cable with waterproof connectors.

Acrylic tubing is a popular electronics container for ROVs, as we’ve seen with an RC Subnautica sub, LEGO submarine, and the Hackaday Prize-winning Underwater Glider.

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