Daisy Chain Of Hacks Lets New Arm Board Run Doom

July 5, 2025 by Tyler August 15 Comments

Running DOOM on ARM? Old hat. Running Doom (2016) on an ARM SBC? Well, that’s a bit more interesting, and [Interfacing Linux] shows us how with this handy guide, and in a video embedded below.

The ARM SBC in question is the Radxa Orion O6, which claims to be the world’s first open source ARMv9 motherboard. It has a 12-core ARM9.2 SoC from Cix, and crucially for gaming, a PCIe x16 slot to fit a graphics card. There’s onboard graphics in the SoC, of course, but that’s only going to cut it for old DOOM, not Doom (2016).

Obviously there is no ARMv9 build of this nine-year-old classic. Thus, a certain degree of hacking is required. An x86 emulation layer called FEX is used to run Steam, which includes the Proton compatibility layer to sit between the Linux system and the Windows system calls the games are making.

So, again: Windows games, running via a compatibility layer on a Linux system running on an x86 emulator, running on another Linux system, running on ARM hardware. Yeah, we’d call that a hack, and just possibly cursed. The amazing thing is that it works. As long as you use a PCI 3.0 graphics card, anyway; apparently newer ones don’t work, or at least not the one [Interfacing Linux] had to try. (Some report better luck with newer NVIDIA cards.) Which is a pity, because every game tested is GPU-throttled on this system. Considering the CPU should be handling all the emulation, that just goes to show how GPU-heavy even 10-year-old games are.

[Interfacing Linux] seems to enjoy running things where they should not; we just wrote up their SteamOS console.

This isn’t the first time a Radxa board has shown up on Hackaday either, but they don’t seem to be nearly as popular as the fruit-flavoured competition for the sort of projects we usually see. If you’ve got a good project using one of these powerful ARM boards– or anything else, don’t hesitate to send us a tip!

Software Defined Retro ROM Makes 8-bit Easy

July 5, 2025 by Tyler August 28 Comments

Like the rest of us, 8-bit hardware is not getting any newer, and failed ROMs are just a fact of life. Of course you can’t call up Commadore corporation for replacement parts anymore, so something is needed. [Peirs Rocks] wasn’t satisfied with the existing options, so he came up with the Software Defined Retro ROM to serve as a drop-in replacement for 2364, 2332, and 2316 ROM chips.

Physically, the Software Defined Retro ROM is a PCB that matches the footprint of the original ROM chip, and holds an STM32F4 family microcontroller with a number of extra pins facing upwards. Some of those pins are for programming, so you can flash the board in-situ without removing it from the system using a Pi Pico. The others pins are jumpers for image selection or chip configuration. Depending which STM32 you use, you can have upto 16 ROM images on the board, at whatever chip select behaviour you require. The ROM’s chip select lines could be configured at the factory to answer to HIGH or LOW, and this board can handle either with a jumper swap.

The documentation on the GitHub is very well done, for which we applaud [Piers]. Instructions and demos are also available in the video embedded below. We could certainly see this hack becoming popular in the retrocomputer community, especially as everything ages and memories continue to, uh, y’know. What were we talking about, again?

Oh, right, ROMs. You might think an mask ROM would last a very long time, but it’s been a very long time since some of these were made. Best to dump them while you still can. If the chip is really far gone electrically, you might try decoding a photograph of the die.

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CIS-4 Is A Monkish Clock Inside A Ceiling Lamp

July 4, 2025 by Tyler August 3 Comments

It’s always clock time at Hackaday, and this time we have an interesting hack of a clock by [danjovic]– the CIS4, a Cistercian digital clock.

The Cistertians, in case you weren’t paying close attention to European holy orders during the 13th to 15th centuries were the group of monks you’d most likely have found us in. They were the hackers of the middle ages, establishing monestaries across western Europe that were chock full of hacks– including their own numeral system. Cistercian numerals were much more efficient (in spaces and penstrokes) than the Roman numerals they replaced, and even the “Arabic” numerals that replaced them. A single glyph could record anything from 1 to 9,999. (The Europeans hadn’t yet cottoned on to zero.)

The Cistertian glyphs reduced to a 4×4 display.

Depending how you wanted to count time, a single glyph could be used; it looks like [danjovic] is using the thousands and hundreds portions of the glyph for hours and the tens and ones for minutes. This is all accomplished with a 4×4 neopixel matrix, run by an Attiny85 Digispark with a DS3231 RTC module keeping time. A slight simplification is required to reduce the glyphs to 4×4, but we don’t think the monks would mind. For those of us who don’t wear tonsures, an easy read mode scrolls the time in Arabic numerals. (Which still aren’t super easy,with only 4×4 LEDs to display them. See the demo video embedded below and try and guess the time.)

One nice quality of life feature is an LDR for ambient light detection, to automatically adjust the neopixels’ brightness. The hackiest part, which we thought was really clever, is the enclosure: it’s a cheap LED ceiling light. This provides a diffuser, housing and mounting hardware with decent design for no effort. A 3D-printed mask sits between the diffuser and the LEDs and doubles as a PCB holder. All very elegant.

[danjovic] did include a buzzer in the design, but does say if its been programed to sound off for matins, nones and vespers. In any case, at least it’s easier to read than his binary-coded-octal clock that we featured a few years back. This isn’t our first look at this number system,so evidently people can read them with practice.

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Video Cable Becomes Transmitter With TEMPEST-LoRa

July 4, 2025 by Tyler August 10 Comments

EFI from cables is something every ham loves to hate. What if you modulated, that, though, using an ordinary cable as an antenna? If you used something ubiquitous like a video cable, you might have a very interesting exploit– which is exactly what [Xieyang Sun] and their colleagues have done with TEMPEST-LoRa, a technique to encode LoRa packets into video files.

The concept is pretty simple: a specially-constructed video file contains information to be broadcast via LoRa– the graphics card and the video cable serve as the Tx, and the Rx is any LoRa module. Either VGA or HDMI cables can be used, though the images to create the LoRa signal are obviously going to differ in each case. The only restriction is that the display resolution must be 1080×1920@60Hz, and the video has to play fullscreen. Fullscreen video might make this technique easy to spot if used in an exploit, but on the other hand, the display does not have to be turned on at the time of transmission. If employed by blackhats, one imagines syncing this to power management so the video plays whenever the screen blanks.

This image sends LoRa. Credit: TEMPEST-LoRa

According to the pre-print, a maximum transmission distance of 81.7m was achieved, and at 21.6 kbps. That’s not blazing fast, sure, but transmission out of a totally air-gapped machine even at dialup speeds is impressive. Code is on the GitHub under an MIT license, though [Xieyang Sun] and the team are white hats, so they point out that it’s provided for academic use. There is a demo video, but as it is on bilbili we don’t have an easy way to embed it. The work has been accepted to the ACM Conference on Computer and Communications Security (2025), so if you’re at the event in Taiwan be sure to check it out.

We’ve seen similar hacks before, like this one that uses an ethernet cable as an antenna. Getting away from RF, others have used fan noise, or even the once-ubiquitous HDD light. (And here we thought casemakers were just cheaping out when they left those off– no, it’s security!)

Thanks to [Xieyang Sun] for the tip! We’ll be checking the tips line for word from you, just as soon as we finish wrapping ferrites around all our cables.

2025 One Hertz Challenge: Electromechanical CMOS Clock Keeps In Step With Mains Frequency

July 4, 2025 by Tyler August 12 Comments

Some people can’t be bothered to read the analog face of a traditional clock. Some people cannot stand the low frequency “hum” of mains current. If you are in either of those categories, you probably don’t want to make [Christian]’s handsome and well-documented electromechanical CMOS clock.

As you might guess from the name, the clock uses CMOS logic, based around a 12 bit counter, to provide the divider circuits 24 (daily) and 60 (minutes and seconds). Specifically, the circuits are based around a CD4040 twelve-bit adder. Those signals go through DAC circuits based around DAC0808 chips to drive some very nice coil meters for hours and minutes in lieu of the traditional clock face. Taking the time to make a CMOS clock circuit from adder chips is respectable enough in this era of instant-gratification through micro-controllers, and we dig the blinkenlights built into the circuits, but it’s what is being added that is where things get really interesting.

[Christian] had the bright idea that a stepper motor could be driven via the mains, simply by using a capacitor to offset the waveforms on the coils by 90 degrees. With a 200-step stepper motor, [Christian] gets one revolution per second out of the 50 Hz grid; this generates the seconds signal for his CMOS chips by the simple expedient of a 3D printed arm and a light barrier. Once per second, the light is interrupted by the spinning arm, creating a pulse for the clock circuits to add up. Check it out in action in the demo video below.

This project also seems to have the distinction of being the first project submitted to our One Hertz Challenge. It’s not just for clocks, but keep an eye on your clock because entries are only open until 9:00 AM Pacific time on August 19th.

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Reliving VHS Memories With NFC And ESPHome

July 3, 2025 by Tyler August 10 Comments

Like many of us of a certain vintage, [Dillan Stock] at The Stock Pot is nostalgic for VHS tapes. It’s not so much the fuzzy picture or the tracking issues we miss, but the physical experience the physical medium brought to movie night. To recreate that magic, [Dillan] made a Modern VHS with NFC and ESPHome.

NFC tags are contained in handsomely designed 3D printed cartridges. You can tell [Dillan] put quite a bit of thought into the industrial design of these: there’s something delightfully Atari-like about them, but they have the correct aspect ratio to hold a miniaturized movie poster as a label. They’re designed to print in two pieces (no plastic wasted on supports) and snap together without glue. The printed reader is equally well thought out, with print-in-place springs for that all important analog clunk.

Electronically, the reader is almost as simple as the cartridge: it holds the NFC reader board and an ESP32. This is very similar to NFC-based audio players we’ve featured before, but it differs in the programming. Here, the ESP32 does nothing related directly to playing media: it is simply programmed to forward the NFC tag id to ESPHome. Based on that tag ID, ESPHome can turn on the TV, cue the appropriate media from a Plex server (or elsewhere), or do… well, literally anything. It’s ESPHome; if you wanted to make this and have a cartridge to start your coffee maker, you could.

If this tickles your nostalgia bone, [Dillan] has links to all the code, 3D files and even the label templates on his site. If you’re not sold yet, check out the video below and you might just change your mind. We’ve seen hacks from The Stock Pot before, everything from a rebuilt lamp to an elegant downspout and a universal remote.

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The door-unlocking mechanism, featuring a 3D printed bevel gear and NEMA 17 stepper.

Hack Swaps Keys For Gang Signs, Everyone Gets In

July 2, 2025 by Tyler August 12 Comments

How many times do you have to forget your keys before you start hacking on the problem? For [Binh], the answer was 5 in the last month, and his hack was to make a gesture-based door unlocker. Which leads to the amusing image of [Binh] in a hallway throwing gang signs until he is let in.

The system itself is fairly simple in its execution: the existing deadbolt is actuated by a NEMA 17 stepper turning a 3D printed bevel gear. It runs 50 steps to lock or unlock, apparently, then the motor turns off, so it’s power-efficient and won’t burn down [Binh]’s room.

The software is equally simple; mediapipe is an ML library that can already do finger detection and be accessed via Python. Apparently gesture recognition is fairly unreliable, so [Binh] just has it counting the number of fingers flashed right now. In this case, it’s running on a Rasberry Pi 5 with a webcam for image input. The Pi connects via USB serial to an ESP32 that is connected to the stepper driver. [Binh] had another project ready to be taken apart that had the ESP32/stepper combo ready to go so this was the quickest option. As was mounting everything with double-sided tape, but that also plays into a design constraint: it’s not [Binh]’s door.

[Binh] is staying in a Hacker Hotel, and as you might imagine, there’s been more penetration testing on this than you might get elsewhere. It turns out it’s relatively straightforward to brute force (as you might expect, given it is only counting fingers), so [Binh] is planning on implementing some kind of 2FA. Perhaps a secret knock? Of course he could use his phone, but what’s the fun in that?

Whatever the second factor is, hopefully it’s something that cannot be forgotten in the room. If this project tickles your fancy, it’s open source on GitHub, and you can check it out in action and the build process in the video embedded below.

After offering thanks to [Binh] for the tip, the remaining words of this article will be spent requesting that you, the brilliant and learned hackaday audience, provide us with additional tips.

Continue reading “Hack Swaps Keys For Gang Signs, Everyone Gets In” →